Digital broadcasting receiving device and digital broadcasting receiving method

Abstract

A digital broadcast receiver apparatus (1) receives a digital broadcast in an OFDM system. A physical channel of the digital broadcast has a partial reception band (Bp) which is a part of a reception band. The digital broadcast receiver apparatus (1) is provided with a plurality of demodulation units (30) and a synthesis unit (50) that synthesizes the plurality of demodulation units (30). In a first operation mode (m1), the plurality of demodulation units (30) process signals in the partial reception band (Bp) of the same physical channel, thereby outputting a plurality of demodulation signals (s1). The synthesis unit (50) performs a process for the partial reception band (Bp) on the basis of the plurality of demodulation signals (s1). In a second operation mode (m2), one demodulation unit (31) among the plurality of demodulation units (30) processes a signal in all the reception band (Bf) including the partial reception band (Bp), thereby outputting one demodulation signal (s2). The synthesis unit (50) performs a process for all the reception band (Bf) on the basis of the one demodulation signal (s2).

Description

Technical Field

[0001] The present disclosure relates to a digital broadcast receiving apparatus for receiving digital broadcasts and a digital broadcast receiving method.

Background Art

[0002] Currently, the practical application of next-generation digital broadcasts is being considered. In the next-generation system, it is considered that the same transmission system using OFDM (Orthogonal Frequency Division Multiplexing) as the current system (ISDB-T: Integrated Services Digital Broadcasting-Terrestrial) will be adopted.

[0003] On the other hand, as a vehicle-mounted receiving apparatus, in order to ensure the quality of received signals, a technique for receiving digital broadcasts by diversity reception is known. As an example of this type of receiving apparatus, Patent Document 1 discloses a vehicle-mounted receiving apparatus that performs diversity reception of digital broadcasts. In this receiving apparatus, the same channel is selected and demodulated in each of the four receiving branches, and the four signals after demodulation are carrier-combined to generate viewing data.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In next-generation digital broadcasting, the amount of data processing required is expected to increase compared to current systems in order to improve the transmission rate. Therefore, if the technology disclosed in Patent Document 1 is applied to the reception of next-generation digital broadcasting, memory will be used for data processing in each of the four reception branches, which will increase the amount of memory installed in the receiving device and lead to increased costs.

[0006] This disclosure aims to provide digital broadcasting receiving equipment, etc., that is compatible with receiving next-generation digital broadcasting systems. [Means for solving the problem]

[0007] A digital broadcast receiving device in one embodiment of the present disclosure is a digital broadcast receiving device that receives OFDM digital broadcasts, wherein the physical channels of the digital broadcasts have a partial reception band which is part of the reception band, and the digital broadcast receiving device comprises a plurality of demodulation units that perform demodulation processing, and a combining unit that combines the outputs of the plurality of demodulation units, wherein in a first operating mode, the plurality of demodulation units output a plurality of demodulated signals by processing the signals of the partial reception band of the same physical channel, and the combining unit performs processing on the partial reception band based on the plurality of demodulated signals output from the plurality of demodulation units, and in a second operating mode different from the first operating mode, one of the plurality of demodulation units outputs a single demodulated signal by processing the signals of the entire reception band including the partial reception band, and the combining unit performs processing on the entire reception band based on the single demodulated signal output from the one demodulation unit.

[0008] A digital broadcast receiving device in one embodiment of the present disclosure is a digital broadcast receiving device that receives OFDM digital broadcasts, wherein the physical channels of the digital broadcasts have a partial reception band which is part of the reception band and a non-partial reception band which is different from the partial reception band, and the digital broadcast receiving device comprises a first demodulation unit and a second demodulation unit which perform demodulation processing, and a combining unit which combines the output of the first demodulation unit and the output of the second demodulation unit, wherein the combining unit performs processing based on the demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit as processing corresponding to the signal in the partial reception band, and performs processing based only on the demodulated signal output from the first demodulation unit as processing corresponding to the signal in the non-partial reception band.

[0009] A digital broadcasting reception method in one embodiment of the present disclosure is a digital broadcasting reception method for receiving an OFDM digital broadcast, wherein the physical channel of the digital broadcast has a partial reception band which is part of the reception band, and the digital broadcasting reception method selectively performs processing by a first operating mode and processing by a second operating mode which is different from the first operating mode, wherein in the processing by the first operating mode, a plurality of demodulation units process the signals of the partial reception band of the same physical channel to output a plurality of demodulation signals, and a combining unit performs processing on the partial reception band based on the plurality of demodulation signals, and in the processing by the second operating mode, one of the plurality of demodulation units processes the signals of the entire reception band including the partial reception band to output a single demodulation signal, and the combining unit performs processing on the entire reception band based on the single demodulation signal.

[0010] A digital broadcasting reception method in one embodiment of the present disclosure is a digital broadcasting reception method for receiving an OFDM digital broadcast, wherein the physical channels of the digital broadcast have a partial reception band which is part of the reception band and a non-partial reception band which is different from the partial reception band, and in the digital broadcasting reception method, as processing corresponding to the signal in the partial reception band, a synthesis process is performed based on the demodulated signal output from a first demodulator and the demodulated signal output from a second demodulator, and as processing corresponding to the signal in the non-partial reception band, processing is performed based only on the demodulated signal output from the first demodulator.

[0011] These comprehensive or specific embodiments may be implemented as a system, method, integrated circuit, computer program, or recording medium such as a computer-readable CD-ROM, or as any combination of a system, method, integrated circuit, computer program, and recording medium. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide a digital broadcasting receiving device, etc., that is compatible with receiving next-generation digital broadcasting systems. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 schematically shows the structure of physical channels in digital broadcasting under current and next-generation systems. [Figure 2] Figure 2 shows the configuration of a digital broadcast receiving device according to Embodiment 1. [Figure 3] Figure 3 shows the configuration of the demodulation unit of the digital broadcast receiving device according to Embodiment 1. [Figure 4A] Figure 4A is a diagram showing the first operating mode of the digital broadcast receiving device according to Embodiment 1. [Figure 4B] Figure 4B shows the second operating mode of the digital broadcast receiving device according to Embodiment 1. [Figure 4C]FIG. 4C is a diagram showing an operation mode when receiving a digital broadcast of the current system by the digital broadcast receiver according to Embodiment 1. [Figure 5] FIG. 5 is a flowchart showing the digital broadcast receiving method according to Embodiment 1. [Figure 6] FIG. 6 is a diagram showing the configuration of the digital broadcast receiver according to Modification 1 of Embodiment 1. [Figure 7A] FIG. 7A is a diagram showing the first operation mode of the digital broadcast receiver according to Modification 1 of Embodiment 1. [Figure 7B] FIG. 7B is a diagram showing the second operation mode of the digital broadcast receiver according to Modification 1 of Embodiment 1. [Figure 8A] FIG. 8A is a diagram showing the second operation mode when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 2 of Embodiment 1 is 32k. [Figure 8B] FIG. 8B is a diagram showing the second operation mode when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 2 of Embodiment 1 is 16k. [Figure 8C] FIG. 8C is a diagram showing the second operation mode when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 2 of Embodiment 1 is 8k. [Figure 9] FIG. 9 is a diagram showing the configuration of the digital broadcast receiver according to Embodiment 2. [Figure 10A] FIG. 10A is a diagram showing the operation of the digital broadcast receiver according to Embodiment 2. [Figure 10B] FIG. 10B is a diagram showing an operation mode when receiving a digital broadcast of the current system by the digital broadcast receiver according to Embodiment 2. [Figure 11] FIG. 11 is a flowchart showing the digital broadcast receiving method according to Embodiment 2. [Figure 12] FIG. 12 is a diagram showing the configuration of the digital broadcast receiver according to Modification 1 of Embodiment 2. [Figure 13]FIG. 13 is a diagram showing the operation of the digital broadcast receiver according to Modification 1 of Embodiment 2. [Figure 14A] FIG. 14A is a diagram showing the operation when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 2 of Embodiment 2 is 32k. [Figure 14B] FIG. 14B is a diagram showing the operation when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 2 of Embodiment 2 is 16k. [Figure 14C] FIG. 14C is a diagram showing the operation when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 2 of Embodiment 2 is 8k. [Figure 15] FIG. 15 is a diagram showing the configuration of the digital broadcast receiver according to Embodiment 3. [Figure 16A] FIG. 16A is a diagram showing the first operation mode of the digital broadcast receiver according to Embodiment 3. [Figure 16B] FIG. 16B is a diagram showing the second operation mode of the digital broadcast receiver according to Embodiment 3. [Figure 16C] FIG. 16C is a diagram showing the operation mode when receiving a digital broadcast in the current system by the digital broadcast receiver according to Embodiment 3. [Figure 17A] FIG. 17A is a diagram showing the second operation mode when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 1 of Embodiment 3 is 32k. [Figure 17B] FIG. 17B is a diagram showing the second operation mode when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 1 of Embodiment 3 is 16k. [Figure 17C] FIG. 17C is a diagram showing the second operation mode when the FFT size of the physical channel processed by the digital broadcast receiver according to Modification 1 of Embodiment 3 is 8k.

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] (Background leading to this disclosure) The circumstances leading to this disclosure will be explained with reference to Figure 1.

[0015] Figure 1 schematically shows the structure of physical channels in digital broadcasting under current and next-generation systems.

[0016] As shown in Figure 1(a), the physical channel of the current system (ISDB-T) consists of 13 segments with a continuous frequency band. This physical channel has a bandwidth of 5.57 MHz, and the bandwidth of one segment is 0.43 MHz. Furthermore, the physical channel is composed of Layer A, which consists of 1 segment, and Layer B, which consists of 12 segments. Layer A is allocated to broadcast signals for reception by mobile devices.

[0017] The current system has an FFT size of 8k (8,192 points: number of subcarriers = 5,617) for physical channels. The FFT size refers to the number of samples used when applying the Fast Fourier Transform (FFT) to a broadcast signal. FFT processing is an example of digital signal processing performed by digital broadcast receivers. The amount of memory required for demodulation processing in a digital broadcast receiver increases proportionally to the number of subcarriers. The FFT size is predetermined by the transmission parameters of the digital broadcast transmitted from the broadcasting station.

[0018] As shown in Figure 1(b), the next-generation system's physical channel consists of 35 segments with consecutive frequency bands. This physical channel has a bandwidth of 5.83 MHz. The bandwidth of the central 9 segments among the 35 segments is 1.50 MHz. These 9 segments constitute a partial reception band and can include a layer equivalent to the current system's A layer. It is believed that in-vehicle digital broadcasting will be distributed using a layer consisting of up to 9 segments.

[0019] In next-generation digital broadcasting, the FFT size of physical channels can take three forms: 8k (8,192 points), 16k (16,384 points), and 32k (32,768 points). In the current system, the maximum FFT size is 8k (8,192 points: number of subcarriers = 5,617), while in the next-generation system, the maximum FFT size is 32k (32,768 points: number of subcarriers = 30,241). Thus, the FFT size of the next-generation system is four times that of the current system, and the number of subcarriers transmitted will also be nearly four times that of the current system. Therefore, if the conventional diversity reception technology is applied directly to the next-generation system, the increased FFT size will require approximately four times the amount of memory (4M: M represents the amount of memory required conventionally (when the FFT size is 8k)) to be installed in the digital broadcasting receiver, leading to increased costs.

[0020] In contrast, the digital broadcasting receiving device of this embodiment has the following configuration in order to be able to receive next-generation digital broadcasts.

[0021] The embodiments will be described below in detail with reference to the drawings. Note that the embodiments described below are all specific examples of the present disclosure. The numerical values, shapes, materials, components, arrangement positions and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, those not described in the independent claims representing an implementation of one embodiment of the present disclosure will be described as arbitrary components. The implementations of the present disclosure are not limited to the current independent claims and may also be expressed by other independent claims.

[0022] Please note that each figure is a schematic diagram and not necessarily a strictly accurate representation. Furthermore, the same reference numerals are used for substantially identical components in each figure, and redundant explanations may be omitted or simplified.

[0023] (Embodiment 1) [Configuration of a digital broadcasting receiver] The configuration of the digital broadcasting receiving device according to Embodiment 1 will be described with reference to Figures 2 and 3.

[0024] Figure 2 shows the configuration of the digital broadcasting receiving device 1 according to Embodiment 1.

[0025] Digital broadcasting receiver 1 is a device that receives OFDM digital broadcasts and is mounted on a mobile device such as a vehicle. In the following, digital broadcasting receiver 1 may be referred to as receiver 1.

[0026] As shown in Figure 2, the receiving device 1 comprises an RF unit (tuner unit) 10, an ADC unit (AD conversion unit) 20, a demodulation unit 30, a combining unit 50, a DIL unit (deinterleaving unit) 60, an error correction unit 70, and a control unit 80. Figure 2 also shows a video and audio output unit 3 that outputs video and audio, and an input unit 4 that receives operation input from the user. Figure 2 also shows a plurality of antennas 2a, 2b, 2c, and 2d connected to the receiving device 1. Antennas 2a to 2d may be built into the receiving device 1.

[0027] The control unit 80 controls the operation of the RF unit 10, ADC unit 20, demodulation unit 30, combining unit 50, DIL unit 60, and error correction unit 70. The control unit 80 includes a memory unit 90. The memory unit 90 has a first memory area 91, a second memory area 92, a third memory area 93, and a fourth memory area 94. Each memory area 91 to 94 holds data for digital signal processing when the receiving device 1 is operating. Although the memory unit 90 is included in the control unit 80, it may reside anywhere on the chip including the demodulation unit 30 and the DIL unit 60, and may consist of one memory macro or multiple memory macros arranged in different locations on the chip. The control unit 80 may also be provided with other memory units different from the memory unit 90. The way in which the demodulation unit 30 shares each of the memory areas 91 to 94 will be described later.

[0028] Input unit 4 is a device that receives operation input from a user using the receiving device 1. Operation input received from the user is, for example, a channel selection input to select one physical channel from multiple physical channels. Operation input received from the user is also a band selection input to select either a part of the band or all of the band of a single physical channel. For example, a part of the band is selected when receiving digital broadcasts on a mobile device, and all of the band is selected when receiving digital broadcasts in a stationary building or the like.

[0029] Here, as shown in Figure 1(b), the bandwidth of 9 segments that constitute a part of the receiving bandwidth is called the partial receiving bandwidth Bp, the bandwidth of the 26 segments excluding the partial receiving bandwidth Bp is called the non-partial receiving bandwidth Bn, and all segments including the partial receiving bandwidth Bp and the non-partial receiving bandwidth Bn are called the full receiving bandwidth Bf.

[0030] In this embodiment, the operation of the receiving device 1 is changed by the band selection input received by the input unit 4. Specifically, the input unit 4 accepts an input to select a signal in a partial receiving band Bp, which is a segment of a physical channel, or an input to select a signal in the entire receiving band Bf, which is the entire segment. The input unit 4 then outputs the operation input received from the user to the control unit 80. Based on the operation input received by the input unit 4, the control unit 80 processes the broadcast signal input from the antenna.

[0031] Broadcast signals, such as digital broadcasts, are input to multiple antennas 2a to 2d. These multiple antennas 2a to 2d are antennas for diversity reception. Diversity reception improves the quality of the received signal by, for example, prioritizing the use of the signal input from the antenna with the best radio wave conditions among the multiple antennas, or by combining the signals received by multiple antennas to suppress noise. The digital broadcast signals input to each antenna 2a to 2d are output to the RF unit 10.

[0032] The RF unit 10 is composed of a first RF unit 11, a second RF unit 12, a third RF unit 13, and a fourth RF unit 14. The RF unit 10 amplifies the broadcast signal of the digital broadcast output from the antenna and generates an analog signal in a predetermined frequency band. For example, the RF unit 10 selects the receiving band to be processed based on the band selection signal output from the control unit 80, and converts the RF signal of the selected receiving band in the desired physical channel into an IF (Intermediate Frequency) signal and outputs it. The analog signal generated by the RF unit 10 is output to the ADC unit 20.

[0033] The ADC unit 20 is composed of a first ADC unit 21, a second ADC unit 22, a third ADC unit 23, and a fourth ADC unit 24. The ADC unit 20 converts the analog signal output from the RF unit 10 into a digital signal and outputs the resulting IF signal to the demodulation unit 30.

[0034] The demodulation unit 30 is composed of a first demodulation unit 31, a second demodulation unit 32, a third demodulation unit 33, and a fourth demodulation unit 34. The demodulation unit 30 performs demodulation processing on the IF signal output from the ADC unit 20. For example, the demodulation unit 30 performs the above demodulation processing based on the band selection signal and control signals (including various setting signals) output from the control unit 80.

[0035] Figure 3 shows the configuration of the demodulation unit 30 of the digital broadcasting receiver 1. Although the first demodulation unit 31 is shown as an example in Figure 3, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 have the same configuration as the first demodulation unit 31.

[0036] As shown in Figure 3, the demodulation unit 30 includes a time-axis processing unit 41 that processes the time axis of the broadcast wave of a digital broadcast, an FFT processing unit 42 connected to the output side of the time-axis processing unit 41, a subcarrier synchronization unit 43 connected to the output side of the FFT processing unit 42, and a transmission path estimation unit 44 connected to the output side of the subcarrier synchronization unit 43. The demodulation unit 30 also has an equalization unit 45 connected to the output side of the subcarrier synchronization unit 43 and the transmission path estimation unit 44, respectively.

[0037] The time-axis processing unit 41 converts the IF signal output from the ADC unit 20 into a baseband signal by orthogonal transformation, and further performs timing synchronization (symbol synchronization) of OFDM symbols. The time-axis processing unit 41 requires a symbol-level amount of memory for the process of performing timing synchronization of OFDM symbols. The signal processed by the time-axis processing unit 41 is output to the FFT processing unit 42.

[0038] Note that the output signal from the RF unit 10 may be a baseband signal instead of an IF signal. In that case, the orthogonal transformation processing in the time axis processing unit 41 is unnecessary. Hereafter, in this embodiment and in other embodiments, only the IF signal will be described, but all relevant parts may be replaced with the baseband signal, and the processing corresponding to the processing in the time axis processing unit 41 should be interpreted accordingly.

[0039] The FFT processing unit 42 converts the signal output from the time-axis processing unit 41 into a frequency-axis signal by performing an FFT operation. The FFT processing unit 42 requires a memory amount corresponding to the FFT size in order to perform the FFT operation according to the FFT size of the broadcast wave. The signal converted by the FFT processing unit 42 is output to the subcarrier synchronization unit 43.

[0040] The subcarrier synchronization unit 43 performs carrier position synchronization processing on the signal output from the FFT processing unit 42. The subcarrier synchronization unit 43 requires a memory amount corresponding to the FFT size for carrier position synchronization processing. The signal processed by the subcarrier synchronization unit 43 is output to the transmission path estimation unit 44 and the equalization unit 45.

[0041] The transmission path estimation unit 44 interpolates the transmission path characteristics of the dispersed pilot signals in the symbol / subcarrier direction. To perform this interpolation, the transmission path estimation unit 44 requires a memory amount corresponding to multiple symbols, depending on the FFT size. The signal interpolated by the transmission path estimation unit 44 is output to the equalization unit 45.

[0042] The equalization unit 45 performs equalization processing on the signal output from the subcarrier synchronization unit 43. The equalization unit 45 also corrects amplitude and phase distortion based on the signal output from the transmission path estimation unit 44 and outputs the corrected signal to the synthesis unit 50. The equalization unit 45 does not necessarily have to be located in the demodulation unit 30, but may be located in the subsequent synthesis unit 50. The equalization processing by the equalization unit 45 may also be performed together with the synthesis in the synthesis unit 50.

[0043] In this way, the demodulation unit 30 demodulates the signal output from the ADC unit 20 and outputs the demodulated signal to the combining unit 50. Specifically, as shown in Figure 2, the first demodulation unit 31 demodulates the signal output from the first ADC unit 21 and outputs this demodulated signal to the combining unit 50. The second demodulation unit 32 demodulates the signal output from the second ADC unit 22 and outputs this demodulated signal to the combining unit 50. The third demodulation unit 33 demodulates the signal output from the third ADC unit 23 and outputs this demodulated signal to the combining unit 50. The fourth demodulation unit 34 demodulates the signal output from the fourth ADC unit 24 and outputs this demodulated signal to the combining unit 50.

[0044] The combining unit 50 is composed of a first combining unit 51 and a second combining unit 52. The demodulated signal output from the demodulation unit 30 is used, for example, as audio playback data in the first combining unit 51 and subsequent units, and as data for extracting various information in the second combining unit 52 and subsequent units.

[0045] The first combining unit 51 combines one or more demodulated signals output from the demodulation unit 30 to generate a combined signal sc1. In this embodiment, the combining process of the combining unit 50 includes not only the process of generating a combined signal based on multiple demodulated signals, but also the process of generating a combined signal based on a single demodulated signal. The first combining unit 51 outputs the combined signal sc1 generated by the combining process to the first DIL unit 61.

[0046] The first DIL unit 61 performs deinterleaving processing on the combined signal sc1 output from the first combining unit 51 in accordance with the broadcasting method of digital broadcasting. The signal processed by the first DIL unit 61 is output to the first error correction unit 71.

[0047] The first error correction unit 71 generates a TS (Transport Stream) signal or a TLV (Type Length Value) signal (hereinafter referred to as the TS signal) by performing correction processing on the signal output from the first DIL unit 61 in accordance with the broadcasting method of digital broadcasting. The TS signal generated by the first error correction unit 71 is output to the video and audio output unit 3. The video and audio output unit 3 performs decoding processing on the TS signal. The video and audio output unit 3 is a display device such as a display and outputs video and audio based on the TS signal output from the receiving device 1.

[0048] The second combining unit 52 combines one or more demodulated signals output from the demodulation unit 30 to generate a combined signal sc2. The second combining unit 52 outputs the combined signal sc2 generated by the combining process to the second DIL unit 62.

[0049] The second DIL unit 62 performs deinterleaving processing on the combined signal sc2 output from the second combining unit 52 in accordance with the broadcasting method of digital broadcasting. The signal processed by the second DIL unit 62 is output to the second error correction unit 72.

[0050] The second error correction unit 72 generates a TS signal by performing correction processing on the signal output from the second DIL unit 62 in accordance with the broadcasting method of digital broadcasting. The TS signal generated by the second error correction unit 72 is output to, for example, a channel information acquisition unit (not shown) for channel searching.

[0051] [Operation of Digital Broadcast Receiving Equipment] The operation of the digital broadcasting receiver 1 will be explained with reference to Figures 4A to 4C. In this example, the method by which the demodulation unit 30 shares each memory area 91 to 94 will be explained. Furthermore, the following explanation will focus on the scene in which the demodulation unit 30 outputs the demodulated signal to the first combining unit 51.

[0052] Figure 4A shows the first operating mode m1 of the digital broadcast receiver 1. Figure 4B shows the second operating mode m2 of the digital broadcast receiver 1. The dashed arrows in Figures 4A and 4B represent signal lines for reading and writing data (the same applies hereafter).

[0053] As described above, the control unit 80 controls the operation of the receiving device 1 based on the operation input received by the input unit 4. Specifically, the control unit 80 outputs a band selection signal and a control signal to the demodulation unit 30 based on the band selection input received by the input unit 4. The demodulation unit 30 performs demodulation processing based on the band selection signal and control signal output from the control unit 80.

[0054] Here, the operating mode for processing signals in the partial reception band Bp is called the first operating mode m1, and the operating mode for processing signals in the entire reception band Bf, including the partial reception band Bp, is called the second operating mode m2. The signals in the partial reception band Bp processed in the first operating mode m1 are signals based on digital broadcasts input from multiple antennas 2a to 2d, which correspond one-to-one with the multiple demodulation units 30. The signals in the entire reception band Bf processed in the second operating mode m2 are signals based on digital broadcasts input from one antenna 2a, which corresponds to the first demodulation unit 31.

[0055] The control unit 80 switches whether to operate the receiving device 1 in a first operating mode m1 or in a second operating mode m2, based on the bandwidth selection input received by the input unit 4.

[0056] In the first operating mode m1 shown in Figure 4A, the multiple demodulation units 30 output multiple demodulated signals s1 by processing signals in a partial reception band Bp of the same physical channel. Specifically, the first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 output demodulated signals s1 by processing signals in a partial reception band Bp.

[0057] The first combining unit 51 performs a combining process on a partial receiving band Bp based on a plurality of demodulated signals s1 output from the first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34. The first combining unit 51 outputs the combined signal sc1 generated by this combining process to the first DIL unit 61.

[0058] Furthermore, the control unit 80 outputs a control signal to the demodulation unit 30 that specifies the memory areas 91 to 94 that the demodulation unit 30 will use when performing demodulation processing. The first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 each perform demodulation processing using the memory areas 91 to 94 based on this control signal.

[0059] For example, the first demodulation unit 31 performs demodulation using the first memory area 91 corresponding to the first demodulation unit 31. The second demodulation unit 32 performs demodulation using the second memory area 92 corresponding to the second demodulation unit 32. The third demodulation unit 33 performs demodulation using the third memory area 93 corresponding to the third demodulation unit 33. The fourth demodulation unit 34 performs demodulation using the fourth memory area 94 corresponding to the fourth demodulation unit 34.

[0060] In the first operating mode m1, the amount of memory allocated to one memory area is the amount of memory required for processing 9-segment digital signals. Here, if the amount of memory allocated to one memory area is M / 4, then the amount of memory required for four memory areas is 4 × M / 4 = M.

[0061] In the second operating mode m2 shown in Figure 4B, the first demodulator 31 among the multiple demodulators 30 outputs a single demodulated signal s2 by processing the signal of the entire receiving band Bf. That is, the first demodulator 31 outputs a single demodulated signal s2 by processing the signal of all segments.

[0062] The first combining unit 51 performs processing on the entire receiving band Bf based on the demodulated signal s2 output from the first demodulation unit 31.

[0063] In the second operating mode m2, the first demodulation unit 31 requires the amount of memory necessary for processing 35-segment digital signals. Therefore, the control unit 80 outputs a control signal to the demodulation unit 30 instructing it to change the access destination to memory areas 91 to 94. Based on the control signal output from the control unit 80, the first demodulation unit 31 accesses not only the first memory area 91 but also other memory areas different from the first memory area 91 to perform demodulation processing. Specifically, the first demodulation unit 31 uses all of the first memory area 91, the second memory area 92, the third memory area 93, and the fourth memory area 94 to perform demodulation processing. In this example, the amount of memory used by the first demodulation unit 31 becomes 4 × M / 4 = M. This makes it possible for the first demodulation unit 31 to process 35-segment digital signals.

[0064] In this way, by changing how the demodulation unit 30 shares each memory area 91 to 94 according to the operating mode of the receiving device 1, it is possible to suppress an increase in the amount of memory installed in the receiving device 1. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0065] Next, other examples of operating modes for the digital broadcasting receiver 1 will be described.

[0066] During the transition period from the current system to the next-generation system, it is expected that both systems will coexist, so it is desirable to be able to receive digital broadcasts of both systems during this transition period. The digital broadcast receiving device 1 according to Embodiment 1 is not limited to next-generation digital broadcasts, but can also receive digital broadcasts of the current system (ISDB-T).

[0067] Figure 4C shows the operating modes when receiving current digital broadcasts with the digital broadcasting receiver 1. Figure 4C shows an example of receiving current broadcast signals using diversity reception.

[0068] In the current operating mode shown in Figure 4C, multiple demodulation units 30 output multiple demodulated signals by processing a signal with an FFT size of 8k for the same physical channel consisting of 13 segments (see Figure 1(a)). Specifically, the first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 output demodulated signals by processing a signal with an FFT size of 8k. The first combining unit 51 performs a combining process on the signal with an FFT size of 8k based on the multiple demodulated signals output from the first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34. The first combining unit 51 outputs the combined signal generated by this combining process to the first DIL unit 61.

[0069] When multiple demodulation units 30 generate multiple demodulated signals, the first demodulation unit 31 processes using the first memory area 91 corresponding to the first demodulation unit 31. The second demodulation unit 32 processes using the second memory area 92 corresponding to the second demodulation unit 32. The third demodulation unit 33 processes using the third memory area 93 corresponding to the third demodulation unit 33. The fourth demodulation unit 34 processes using the fourth memory area 94 corresponding to the fourth demodulation unit 34.

[0070] In the current operating mode, the amount of memory required to process a signal with an FFT size of 8k is M / 4. Therefore, the amount of memory required for the four memory areas is 4 × M / 4 = M. According to this example, the amount of memory used in the current system can be set to M. In terms of memory capacity, the receiving device 1 of this embodiment is also capable of receiving digital broadcasts using the current system.

[0071] [How to receive digital broadcasts] Figure 5 is a flowchart of the digital broadcasting reception method according to Embodiment 1.

[0072] In this digital broadcast reception method, the control unit 80 first determines whether to receive the digital broadcast using the next-generation system or the current system (step S10). This determination is made, for example, by user input to the input unit 4.

[0073] If the control unit 80 determines that it will receive the digital broadcast using the current system, it outputs control signals to the RF unit 10, demodulation unit 30, DIL unit 60, and error correction unit 70 to receive the digital broadcast using the current system. The receiving device 1 then processes the signal for the digital broadcast using the current system (step S11).

[0074] On the other hand, if the control unit 80 determines that it will receive digital broadcasting using the next-generation system, it proceeds to the next step and determines whether to receive the signal from the partial reception band Bp or the full reception band Bf (step S20). This determination is made, for example, by a band selection input from the user to the input unit 4. Note that step S20 may be executed simultaneously with step S10.

[0075] When the control unit 80 determines that it is receiving a signal in a partial reception band Bp, it operates the receiving device 1 in a first operating mode m1 (step S21). The control unit 80 outputs a band selection signal to the RF unit 10, demodulation unit 30, DIL unit 60, and error correction unit 70 so that they perform digital broadcast signal processing in the first operating mode m1. For example, multiple demodulation units 30 output multiple demodulated signals s1 by processing signals in the partial reception band Bp of the same physical channel. The first combining unit 51 performs processing on the partial reception band Bp based on the multiple demodulated signals s1.

[0076] When generating multiple demodulated signals s1, the first demodulation unit 31 performs demodulation using the first memory area 91 corresponding to the first demodulation unit 31. The second demodulation unit 32 performs demodulation using the second memory area 92 corresponding to the second demodulation unit 32. The third demodulation unit 33 performs demodulation using the third memory area 93 corresponding to the third demodulation unit 33. The fourth demodulation unit 34 performs demodulation using the fourth memory area 94 corresponding to the fourth demodulation unit 34.

[0077] On the other hand, if the control unit 80 determines that it is receiving a signal across the entire reception band Bf, it operates the receiving device 1 in a second operating mode m2 (step S22). The control unit 80 outputs band selection signals to the RF unit 10, demodulation unit 30, DIL unit 60, and error correction unit 70 so that they can perform digital broadcast signal processing in the second operating mode m2. For example, one of the multiple demodulation units 30, demodulation unit 31, outputs a single demodulated signal s2 by processing the signal across the entire reception band Bf. The first combining unit 51 performs processing on the entire reception band Bf based on this single demodulated signal s2.

[0078] When generating a demodulated signal s2, one demodulator 31 accesses other memory areas different from the first memory area 91 in addition to the first memory area 91 to perform demodulation processing. Specifically, one demodulator 31 uses all of the first memory area 91, the second memory area 92, the third memory area 93, and the fourth memory area 94 to perform demodulation processing.

[0079] In this way, by changing how the demodulation unit 30 shares each memory area 91 to 94 depending on the operating mode when receiving digital broadcasts, it is possible to provide a reception method that is compatible with the reception of next-generation digital broadcasts.

[0080] [Modification 1 of Embodiment 1] A modification 1 of Embodiment 1 will be described with reference to Figures 6 to 7B. In this modification 1, an example will be described in which the receiving device 1 is equipped with a pre-combination unit 46 and a selection unit 47.

[0081] Figure 6 shows the configuration of a digital broadcasting receiving device 1 according to a modified example 1 of Embodiment 1.

[0082] The receiver 1 of the modified example 1 also includes an RF unit 10, an ADC unit 20, a demodulation unit 30, a combining unit 50, a DIL unit 60, an error correction unit 70, and a control unit 80. The RF unit 10, ADC unit 20, demodulation unit 30, combining unit 50, DIL unit 60, error correction unit 70, and control unit 80 are the same as in the first embodiment.

[0083] In the receiving device 1 of the modified example 1, the first demodulation unit 31 has a pre-combination unit 46 that is different from the combining unit 50, and a selection unit 47. Although not shown in Figure 6, the first demodulation unit 31 of the modified example 1 has the same functional blocks as the demodulation unit shown in Figure 3.

[0084] The pre-combination unit 46 combines the signal being processed by the first demodulation unit 31 with the signal being processed by another demodulation unit different from the first demodulation unit 31 (for example, the second demodulation unit 32) to generate a combined signal sp. The combined signal sp generated by the pre-combination unit 46 is output to the selection unit 47.

[0085] Note that the signal being processed by the first demodulation unit 31 and the signals being processed by the other demodulation units are the same signals as the signals input to the time-axis processing unit 41 or the FFT processing unit 42 shown in Figure 3 (Figure 6 illustrates the case where the signals input to the time-axis processing unit 41 are combined). Also, although Figure 6 shows the second demodulation unit 32 as an example of the other demodulation unit, it is not limited to this, and the other demodulation unit may be the third demodulation unit 33 or the fourth demodulation unit 34.

[0086] The selection unit 47 receives both the signal being processed by the first demodulation unit 31 and the combined signal sp output from the pre-combination unit 46. The selection unit 47 selects either the signal being processed by the first demodulation unit 31 or the combined signal sp output from the pre-combination unit 46. Which signal the selection unit 47 selects is determined by the operating mode of the receiving device 1.

[0087] Figure 7A shows the first operating mode m1 of the digital broadcast receiving device 1 according to Modification 1. Figure 7B shows the second operating mode m2 of the digital broadcast receiving device 1 according to Modification 1.

[0088] The signals in the partial reception band Bp processed in the first operating mode m1 are signals based on digital broadcasts input from multiple antennas 2a to 2d, which correspond one-to-one with the multiple demodulation units 30. The signals in the full reception band Bf processed in the second operating mode m2 are signals based on digital broadcasts input from two antennas 2a and 2b, which correspond to the first demodulation unit 31 and the second demodulation unit 32.

[0089] As shown in Figure 7A, in the first operating mode m1, the selection unit 47 selects the signal being processed by the first demodulation unit 31. The first demodulation unit 31 then continues processing the signal being processed by the first demodulation unit 31. The way in which the demodulation unit 30 shares each memory area 91 to 94 is the same as in the first operating mode m1 of Embodiment 1.

[0090] As shown in Figure 7B, in the second operating mode m2, the selection unit 47 selects the synthesized signal sp output from the pre-synthesis unit 46. The first demodulation unit 31 then processes this synthesized signal sp. The way in which the demodulation unit 30 shares each memory area 91 to 94 is the same as in the second operating mode m2 of Embodiment 1.

[0091] For example, in the second operating mode m2 of Embodiment 1, a single antenna 2a is used to receive signals across the entire reception band Bf, which tends to degrade the quality of the received broadcast signal. In contrast, in Modification 1, the broadcast signals received by two antennas 2a and 2b are combined, allowing the pre-combination unit 46 to generate a combined signal sp with suppressed noise. Then, in the second operating mode m2, the selection unit 47 selects the combined signal sp output from the pre-combination unit 46, and the first demodulation unit 31 processes the selected combined signal sp. According to Modification 1, the quality of the signal processed after the pre-combination unit 46 can be improved.

[0092] [Modification 2 of Embodiment 1] Modification 2 of Embodiment 1 will be described with reference to Figures 8A to 8C. Modification 2 describes an example in which the FFT size of the physical channels of the next-generation digital broadcasting system is 32k, 16k, or 8k. Here, we will focus on the second operating mode m2.

[0093] Figure 8A shows the second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiver 1 is 32k.

[0094] In the operating mode shown in Figure 8A, the first demodulation unit 31 of the multiple demodulation units 30 outputs a single demodulated signal by processing the signal of the entire reception band Bf. The first demodulation unit 31 performs demodulation processing by accessing other storage areas different from the first storage area 91, in addition to the first storage area 91. Specifically, the first demodulation unit 31 performs demodulation processing using all of the first storage area 91, the second storage area 92, the third storage area 93, and the fourth storage area 94.

[0095] In this example, the amount of memory used by the first demodulation unit 31 is 4 × M / 4 = M. Therefore, even when the FFT size of the physical channel is 32k, it is possible to suppress an increase in the amount of memory installed in the receiving device 1.

[0096] Figure 8B shows the second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiving device 1 is 16k. The figure also shows an example of diversity reception using two antennas 2a and 2c.

[0097] In the operating mode shown in Figure 8B, the first demodulation unit 31 and the third demodulation unit 33 of the multiple demodulation units 30 process the signal of the entire reception band Bf and output two demodulated signals. The first demodulation unit 31 and the third demodulation unit 33 access other memory areas different from the first memory area 91 and the third memory area 93 in addition to the first memory area 91 and the third memory area 93 to perform demodulation processing. Specifically, the first demodulation unit 31 uses the first memory area 91 and the second memory area 92 to perform demodulation processing. The third demodulation unit 33 uses the third memory area 93 and the fourth memory area 94 to perform demodulation processing.

[0098] In this example, the amount of memory used by the first demodulation unit 31 is 2 × M / 4 = M / 2, and the amount of memory used by the third demodulation unit 33 is 2 × M / 4 = M / 2, so the total amount of memory used is M. Therefore, even when the FFT size of the physical channel is 16k, it is possible to suppress an increase in the amount of memory installed in the receiving device 1.

[0099] Figure 8C shows the second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiving device 1 is 8k. The figure also shows an example of diversity reception using four antennas 2a to 2d.

[0100] In the operating mode shown in Figure 8C, the multiple demodulation units 30 process signals across the entire reception bandwidth Bf to output four demodulated signals. The first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 access the first memory area 91, the second memory area 92, the third memory area 93, and the fourth memory area 94, respectively, to perform demodulation processing. Specifically, the first demodulation unit 31 uses the first memory area 91, the second demodulation unit 32 uses the second memory area 92, the third demodulation unit 33 uses the third memory area 93, and the fourth demodulation unit 34 uses the fourth memory area 94 to perform demodulation processing.

[0101] In this example, the amount of memory used by each demodulation unit 30 is M / 4, and the total amount of memory used is M. Therefore, even when the FFT size of the physical channel is 8k, it is possible to suppress an increase in the amount of memory installed in the receiving device 1.

[0102] Furthermore, Modification 2 of this embodiment 1 can be applied to systems that do not have a partial reception bandwidth. For example, it can be applied to DVB-T2 (Digital Video Broadcasting-Terrestrial 2) and ATSC3.0 (Advanced Television Systems Committee 3.0), which have FFT sizes up to 32k, and systems similar to these, as long as the FFT size exceeds 8k. In addition, for systems like ATSC3.0 where the FFT size differs for each subframe, for example, if subframe #1 has an FFT size of 8k and subframe #2 has an FFT size of 32k, the system may operate in the operating mode shown in Figure 8C when receiving subframe #1, and in the operating mode shown in Figure 8A when receiving subframe #2.

[0103] (Embodiment 2) [Configuration of a digital broadcasting receiver] The configuration of the digital broadcast receiving device 1A according to Embodiment 2 will be described with reference to Figure 9. In this example, a case will be described in which the partial reception band Bp and the non-partial reception band Bn are received via antenna 2a, and the partial reception band Bp is received via antenna 2b.

[0104] The signal in the partial reception band Bp is a signal based on digital broadcasting input from multiple antennas 2a and 2b, which correspond one-to-one with the first demodulator 31 and the second demodulator 32. The signal in the non-partial reception band Bn is a signal based on digital broadcasting input from one antenna 2a, which corresponds to the first demodulator 31.

[0105] Figure 9 shows the configuration of the digital broadcasting receiving device 1A according to Embodiment 2.

[0106] Digital broadcasting receiver 1A is a device that receives OFDM digital broadcasts and is mounted on a mobile device such as a vehicle. In the following, digital broadcasting receiver 1A may be referred to as receiver 1A.

[0107] As shown in Figure 9, the receiving device 1A comprises an RF unit 10, an ADC unit 20, a demodulation unit 30, a combining unit 51, a DIL unit 61, an error correction unit 71, and a control unit 80. Figure 9 also shows a video and audio output unit 3 that outputs video and audio, and an input unit 4 that receives user input. Figure 9 also shows a plurality of antennas 2a and 2b connected to the receiving device 1A. Antennas 2a and 2b may be built into the receiving device 1A.

[0108] The control unit 80 controls the operation of the RF unit 10, ADC unit 20, demodulation unit 30, combining unit 51, DIL unit 61, and error correction unit 71. The control unit 80 includes a storage unit 90. The storage unit 90 has a first storage area 91A and a second storage area 92A. The storage capacity of the first storage area 91A is larger than that of the second storage area 92A. Each storage area 91A and 92A holds data for digital signal processing when the receiving device 1A is in operation. The way in which the demodulation unit 30 shares each storage area 91A and 92A will be described later.

[0109] In this embodiment, the input unit 4 outputs the operation input received from the user to the control unit 80. Based on the operation input received by the input unit 4, the control unit 80 processes the broadcast signals input from antennas 2a and 2b.

[0110] Multiple antennas 2a and 2b receive broadcast signals such as digital broadcasts. These multiple antennas 2a and 2b are designed for diversity reception. The digital broadcast signals input to each antenna 2a and 2b are output to the RF unit 10.

[0111] The RF unit 10 is composed of a first RF unit 11 and a second RF unit 12. The analog signal generated by the RF unit 10 is output to the ADC unit 20.

[0112] The ADC unit 20 is composed of a first ADC unit 21 and a second ADC unit 22. The ADC unit 20 converts the analog signal output from the RF unit 10 into a digital signal and outputs the IF signal after digital conversion to the demodulation unit 30.

[0113] The demodulation unit 30 is composed of a first demodulation unit 31 and a second demodulation unit 32. The demodulation unit 30 performs demodulation processing on the IF signal output from the ADC unit 20. For example, the demodulation unit 30 performs the above demodulation processing based on the band selection signal and control signals (including various setting signals) output from the control unit 80.

[0114] The demodulation unit 30 demodulates the signal output from the ADC unit 20 and outputs the demodulated signal to the combining unit 51. Specifically, as shown in Figure 9, the first demodulation unit 31 demodulates the signal output from the first ADC unit 21 and outputs this demodulated signal to the combining unit 51. The second demodulation unit 32 demodulates the signal output from the second ADC unit 22 and outputs this demodulated signal to the combining unit 51.

[0115] The combining unit 51 combines one or more demodulated signals output from the demodulation unit 30 to generate a combined signal sc1. In this embodiment, the combining process of the combining unit 51 includes not only the process of generating a combined signal based on multiple demodulated signals, but also the process of generating a combined signal based on a single demodulated signal. The combining unit 51 outputs the combined signal sc1 generated by the combining process to the DIL unit 61.

[0116] The DIL unit 61 performs deinterleaving processing on the combined signal sc1 output from the combined unit 51 in accordance with the broadcasting method of digital broadcasting. The signal processed by the DIL unit 61 is output to the error correction unit 71.

[0117] The error correction unit 71 generates a TS signal by performing correction processing on the signal output from the DIL unit 61 in accordance with the broadcasting method of digital broadcasting. The TS signal generated by the error correction unit 71 is output to the video and audio output unit 3.

[0118] [Operation of Digital Broadcast Receiving Equipment] The operation of the digital broadcasting receiver 1A will be explained with reference to Figures 10A and 10B. In this example, the method by which the demodulation unit 30 shares the memory areas 91A and 92A will be explained.

[0119] Figure 10A is a diagram showing the operation of the digital broadcasting receiving device 1A according to Embodiment 2.

[0120] The control unit 80 controls the operation of the receiving device 1A based on the operation input received by the input unit 4.

[0121] The first demodulation unit 31 outputs a demodulated signal s11 by processing the signal of the entire receiving band Bf of the physical channel. The first demodulation unit 31 performs demodulation processing using the first memory area 91A corresponding to the first demodulation unit 31. The second demodulation unit 32 outputs a demodulated signal s12 by processing the signal of a portion of the receiving band Bp of the physical channel. The second demodulation unit 32 performs demodulation processing using the second memory area 92A corresponding to the second demodulation unit 32.

[0122] The amount of memory allocated to the first storage area 91A is the amount of memory required for processing 35-segment digital signals. The amount of memory allocated to the second storage area 92A is the amount of memory required for processing 9-segment digital signals. Here, if the amount of memory required for processing 35-segment digital signals is M, then the amount of memory used in the receiving device 1A of Embodiment 2 is (M + M / 4). Therefore, it is possible to suppress an increase in the amount of memory installed in the receiving device 1A compared to the conventional memory amount of 2M.

[0123] When processing a signal in a partial reception band Bp, the combining unit 51 performs processing based on the demodulated signal s11 output from the first demodulation unit 31 and the demodulated signal s12 output from the second demodulation unit 32.

[0124] Furthermore, when processing the non-partial reception band Bn, the combining unit 51 processes based only on the demodulated signal s11 output from the first demodulation unit 31. Note that the demodulated signal s12 output from the second demodulation unit 32 does not include signals related to the non-partial reception band Bn, so the signal of 0 from the second demodulation unit 32 is combined with the signal related to the non-partial reception band Bn output from the first demodulation unit 31. Therefore, the combining unit 51 does not substantially perform combining processing on the non-partial reception band Bn. The combining unit 51 outputs the combined signal sc1 generated by this combining processing to the DIL unit 61.

[0125] For example, when receiving a signal in the partial reception band Bp using one antenna 2a, the quality of the received broadcast signal tends to be lower compared to when receiving the signal in the partial reception band Bp using two antennas 2a and 2b. In contrast, in Embodiment 2, when processing the partial reception band Bp, the broadcast signals received by the two antennas 2a and 2b are combined, so a combined signal sc1 with suppressed noise can be generated. According to Embodiment 2, the quality of the signal in the partial reception band Bp can be improved.

[0126] Next, we will describe other examples of the operating modes of the digital broadcasting receiver 1A.

[0127] During the transition period from the current system to the next-generation system, it is expected that both systems will coexist, so it is desirable to be able to receive digital broadcasts of both systems during this transition period. The digital broadcast receiving device 1A according to Embodiment 2 is not limited to next-generation digital broadcasts, but can also receive digital broadcasts of the current system (ISDB-T).

[0128] Figure 10B shows the operating modes when receiving current digital broadcasts with the digital broadcasting receiver 1A. Figure 10B shows an example of receiving current broadcast signals using diversity reception.

[0129] In the current operating mode shown in Figure 10B, the first demodulator 31 and the second demodulator 32 output their respective demodulated signals by processing a signal with an FFT size of 8k for the same physical channel consisting of 13 segments (see Figure 1(a)). Specifically, the first demodulator 31 and the second demodulator 32 output demodulated signals by processing a signal with an FFT size of 8k.

[0130] The combining unit 51 performs a combining process on a signal with an FFT size of 8k based on the multiple demodulated signals output from the first demodulation unit 31 and the second demodulation unit 32. The combining unit 51 outputs the combined signal generated by this combining process to the DIL unit 61.

[0131] In the current operating mode, the amount of memory required to process a signal with an FFT size of 8k is M / 4. Therefore, the amount of memory required for the two memory areas is 2 × M / 4 = M / 2. According to this example, the amount of memory used in the current system can be M / 2. The receiving device 1A of this embodiment is also capable of receiving digital broadcasts using the current system.

[0132] [How to receive digital broadcasts] Figure 11 is a flowchart of the digital broadcasting reception method according to Embodiment 2.

[0133] In this digital broadcast reception method, the control unit 80 first determines whether to receive the digital broadcast using the next-generation system or the current system (step S10). This determination is made, for example, by user input to the input unit 4.

[0134] If the control unit 80 determines that it will receive the digital broadcast using the current system, it outputs control signals to the RF unit 10, demodulation unit 30, DIL unit 61, and error correction unit 71 to receive the digital broadcast using the current system. The receiving device 1A then processes the signal for the digital broadcast using the current system (step S11).

[0135] On the other hand, if the control unit 80 determines that it will receive digital broadcasting using the next-generation system, it performs a synthesis process based on the demodulated signal output from the first demodulation unit 31 and the demodulated signal output from the second demodulation unit 32 as processing corresponding to the signal in the partial reception band Bp (step S21A).

[0136] Furthermore, the control unit 80 performs processing on the non-partial reception band Bn based only on the demodulated signal output from the first demodulation unit 31 as processing for the non-partial reception band Bn (step S22A). Step S22A may be performed before step S21A or simultaneously with step S21A.

[0137] During steps S21A and S22A, the first demodulation unit 31 performs demodulation processing using the first memory area 91A corresponding to the first demodulation unit 31. The second demodulation unit 32 performs demodulation processing using the second memory area 92A corresponding to the second demodulation unit 32. That is, the first memory area 91A is used to process both the partial reception band Bp and the non-partial reception band Bn, and the second memory area 92A is used to process the partial reception band Bp.

[0138] In this way, without increasing the amount of memory, the signal quality can be improved for the partial reception bandwidth Bp, and a reception method that can handle the reception of next-generation digital broadcasts can be provided.

[0139] [Modification 1 of Embodiment 2] A modification 1 of Embodiment 2 will be described with reference to Figures 12 and 13. In this modification 1, an example will be described in which the receiving device 1A is equipped with a pre-combination unit 46A and a selection unit 47A.

[0140] Figure 12 shows the configuration of a digital broadcast receiving device 1A according to a modified example 1 of Embodiment 2.

[0141] The receiving device 1A of this modified example 1 also includes an RF unit 10, an ADC unit 20, a demodulation unit 30, a combining unit 50, a DIL unit 61, an error correction unit 71, and a control unit 80. The RF unit 10, ADC unit 20, demodulation unit 30, combining unit 50, DIL unit 61, error correction unit 71, and control unit 80 are the same as in Embodiment 2.

[0142] In the receiving device 1A of the modified example 1, the first demodulation unit 31 has a pre-combination unit 46A that is different from the combining unit 50 and a selection unit 47A.

[0143] The pre-combination unit 46A combines the signal being processed in the first demodulation unit 31 with the signal being processed in the second demodulation unit 32, which is different from the first demodulation unit 31, to generate a combined signal sp. The combined signal sp generated by the pre-combination unit 46A is output to the selection unit 47A.

[0144] Furthermore, the signal being processed by the first demodulation unit 31 and the signal being processed by the second demodulation unit 32 are the same signals as the signal input to the time axis processing unit 41 or the signal input to the FFT processing unit 42.

[0145] The selection unit 47A receives both the signal being processed by the first demodulation unit 31 and the combined signal sp output from the pre-combination unit 46A. The selection unit 47A selects either the signal being processed by the first demodulation unit 31 or the combined signal sp output from the pre-combination unit 46A. The user can set which signal the selection unit 47A selects as appropriate. For example, if the system is compatible with next-generation systems, it is not possible to combine the signals in the combination unit 51 after demodulating the entire bandwidth, so the signals are combined beforehand, and the output sp from the pre-combination unit 46A is selected. If the system is compatible with current systems, sufficient combining is possible in the combination unit 51, so the pass-through signal is selected instead of the output sp from the pre-combination unit 46A. The required output for the partial reception bandwidth Bp and the non-partial reception bandwidth Bn is determined by a request from an external device or by an operation input from the input unit 4.

[0146] Figure 13 shows the operation of the digital broadcast receiving device 1A according to a modified example 1 of Embodiment 2.

[0147] The selection unit 47A of the receiving device 1A selects the signal being processed by the first demodulation unit 31 as the signal corresponding to the signal in the partial receiving band Bp. The first demodulation unit 31 then continues processing the signal being processed by the first demodulation unit 31. The way in which the demodulation unit 30 shares the respective memory areas 91A and 92A is the same as in the second embodiment.

[0148] Furthermore, the selection unit 47A selects the synthesized signal sp output from the pre-synthesizing unit 46A as the processing option for the signal in the non-partial reception band Bn. The first demodulation unit 31 then processes this synthesized signal sp. The way in which the demodulation unit 30 shares each memory area 91A, 91A is the same as in the second embodiment.

[0149] In this modified example 1, the broadcast signals received by the two antennas 2a and 2b are combined, so the pre-combining unit 46A can generate a combined signal sp with suppressed noise. The selection unit 47A then selects the combined signal sp output from the pre-combining unit 46A as the processing option for the signal in the non-partial reception band Bn, and the first demodulation unit 31 processes the selected combined signal sp. As a result, the quality of the signal processed in stages after the pre-combining unit 46A can be improved.

[0150] In this modified example 1, the selection unit 47A selects the signal being processed by the first demodulation unit 31 as the processing option corresponding to the signal in the partial reception band Bp, and the first demodulation unit 31 continues processing the signal being processed by the first demodulation unit 31. Therefore, when the combining unit 51 combines the signals in the partial reception band Bp, the combining process can be performed with the signal levels matched, and the quality of the signal output from the combining unit 51 can be improved.

[0151] [Modification 2 of Embodiment 2] A second modification of Embodiment 2 will be described with reference to Figures 14A to 14C. This second modification describes an example where the FFT size of the physical channels of the next-generation digital broadcasting system is 32k, 16k, or 8k.

[0152] Figure 14A shows the operation when the FFT size of the physical channel processed by the digital broadcast receiver 1A is 32k.

[0153] The first demodulation unit 31 outputs a demodulated signal by processing the signal of the entire receiving band Bf of the physical channel. The first demodulation unit 31 performs demodulation processing using the first memory area 91A corresponding to the first demodulation unit 31. The second demodulation unit 32 outputs a demodulated signal by processing the signal of a portion of the receiving band Bp of the physical channel. The second demodulation unit 32 performs demodulation processing using the second memory area 92A corresponding to the second demodulation unit 32.

[0154] The amount of memory allocated to the first memory area 91A is the amount of memory required for 35-segment digital signal processing. The amount of memory allocated to the second memory area 92A is the amount of memory required for 9-segment digital signal processing. Here, if the amount of memory required for 35-segment digital signal processing is M, then the amount of memory used in the receiver 1A of Embodiment 2 is (M + M / 4). Therefore, even when the FFT size of the physical channel is 32k, it is possible to suppress an increase in the amount of memory installed in the receiver 1A.

[0155] Figure 14B shows the operation when the FFT size of the physical channel processed by the digital broadcast receiver 1A is 16k. The figure also shows an example of diversity reception using two antennas 2a and 2b.

[0156] The first demodulation unit 31 outputs a demodulated signal by processing the signal in the entire receiving band Bf of the physical channel. The second demodulation unit 32 outputs a demodulated signal by processing the signal in a partial receiving band Bp of the physical channel.

[0157] In this case, the demodulation process of the second demodulation unit 32 requires the amount of memory necessary to process a signal with an FFT size of 16k. On the other hand, the first memory area 91A accessed by the first demodulation unit 31 is originally allocated the amount of memory M necessary for processing a 35-segment digital signal, which is sufficient memory for processing a signal with an FFT size of 16k. Therefore, the control unit 80 outputs a control signal to the demodulation unit 30 instructing it to change the access destination of memory areas 91A and 92A. Based on the control signal output from the control unit 80, the second demodulation unit 32 accesses the M / 4 area of ​​the first memory area 91A in addition to the second memory area 92A and performs demodulation processing. On the other hand, the first demodulation unit 31 performs demodulation processing using half (M / 2) of the first memory area 91A corresponding to the first demodulation unit 31.

[0158] In this example, the amount of memory used by the first demodulation unit 31 is M / 2, and the amount of memory used by the second demodulation unit 32 is M / 2, resulting in a total amount of memory used of M. Therefore, even when the FFT size of the physical channel is 16k, it is possible to suppress an increase in the amount of memory installed in the receiving device 1A.

[0159] Figure 14C shows the operation when the FFT size of the physical channel processed by the digital broadcast receiver 1A is 8k. The figure also shows an example of diversity reception using two antennas 2a and 2b.

[0160] The first demodulation unit 31 outputs a demodulated signal by processing the signal of the entire receiving band Bf of the physical channel. The first demodulation unit 31 performs demodulation processing using the first memory area 91A corresponding to the first demodulation unit 31. The second demodulation unit 32 outputs a demodulated signal by processing the signal of a portion of the receiving band Bp of the physical channel. The second demodulation unit 32 performs demodulation processing using the second memory area 92A corresponding to the second demodulation unit 32.

[0161] In this example, the amount of memory used by the first demodulation unit 31 and the second demodulation unit 32 is M / 4, and the total amount of memory used is M / 2. Therefore, even when the FFT size of the physical channel is 8k, it is possible to suppress an increase in the amount of memory installed in the receiving device 1A.

[0162] Furthermore, variations 1 and 2 of Embodiment 2 may be combined. In this case, the selection unit may select the combined signal sp, which is the output of the pre-combination unit 46A, when the FFT size is 32k, and select the through signal when the FFT size is 16k or 8k. When the FFT size is 16k or 8k, the combined unit 51 can combine signals across the entire bandwidth, so by using the through signal instead of the combined signal sp from the pre-combination unit 46A, the combined unit 51 can perform optimal combining for each subcarrier.

[0163] (Embodiment 3) [Configuration and Operation of Digital Broadcast Receiving Equipment] The configuration of the digital broadcasting receiver 1B according to Embodiment 3 will be described with reference to Figure 15. Embodiment 3 describes an example in which the digital broadcasting receiver 1B is provided with memory areas 95B and 96B used by the DIL units 61 and 62.

[0164] Figure 15 shows the configuration of the digital broadcasting receiving device 1B according to Embodiment 3.

[0165] Digital broadcasting receiver 1B is a device that receives OFDM digital broadcasts and is mounted on a mobile device such as a vehicle. In the following, digital broadcasting receiver 1B may be referred to simply as receiver 1B.

[0166] As shown in Figure 15, the receiving device 1B comprises an RF unit 10, an ADC unit 20, a demodulation unit 30, a combining unit 50, a DIL unit 60, an error correction unit 70, and a control unit 80. Figure 15 also shows a video and audio output unit 3 that outputs video and audio, and an input unit 4 that receives operation input from the user. Figure 15 also shows a plurality of antennas 2a, 2b, 2c, and 2d connected to the receiving device 1B.

[0167] The configuration of the RF unit 10, ADC unit 20, demodulation unit 30, synthesis unit 50, DIL unit 60, and error correction unit 70 is the same as in Embodiment 1.

[0168] The storage unit 90 included in the control unit 80 has a first storage area 91, a second storage area 92, a third storage area 93, and a fourth storage area 94. The storage unit 90 of Embodiment 3 further has a fifth storage area 95B and a sixth storage area 96B. Each storage area 95B and 96B holds data for digital signal processing when the receiving device 1B is operating. Although the storage unit 90 is included in the control unit 80, it may reside anywhere on a single chip including the demodulation unit 30 and the DIL unit 60, and may consist of one memory macro or multiple memory macros arranged in different locations on the chip. The control unit 80 may also be provided with other storage units different from the storage unit 90. In this example, the method of sharing the storage areas 95B and 96B by the DIL units 61 and 62 will be described.

[0169] Figure 16A shows the first operating mode m1 of the digital broadcast receiving device 1B. Figure 16B shows the second operating mode m2 of the digital broadcast receiving device 1B.

[0170] The control unit 80 controls the operation of the receiving device 1B based on the operation input received by the input unit 4. Specifically, the control unit 80 outputs a band selection signal and a control signal to the demodulation unit 30 based on the band selection input received by the input unit 4. The demodulation unit 30 performs demodulation processing based on the band selection signal and control signal output from the control unit 80. The control unit 80 switches whether to operate the receiving device 1B in the first operating mode m1 or in the second operating mode m2 based on the band selection input received by the input unit 4.

[0171] In the first operating mode m1 shown in Figure 16A, the DIL unit 60 generally processes signals in partial receiving bandwidths Bp of different physical channels. However, since Figure 16A illustrates the case where all outputs of the demodulation units 31 to 34 are input to the combining unit 51, only the DIL unit 61 needs to operate. Below, the DIL unit 62 operates only when at least one of the outputs of the demodulation units 31 to 34 is input to the combining unit 52 and processed.

[0172] The first DIL unit 61 performs deinterleaving processing on the composite signal sc1 output from the first synthesis unit 51 in accordance with the digital broadcasting method. The signal processed by the first DIL unit 61 is output to the first error correction unit 71. The first error correction unit 71 generates a TS signal by performing correction processing on the signal output from the first DIL unit 61 in accordance with the digital broadcasting method. The TS signal generated by the first error correction unit 71 is output to the video and audio output unit 3.

[0173] The second DIL unit 62 performs deinterleaving processing on the combined signal sc2 output from the second combining unit 52 in accordance with the digital broadcasting method. The signal processed by the second DIL unit 62 is output to the second error correction unit 72. The second error correction unit 72 generates a TS signal by performing correction processing on the signal output from the second DIL unit 62 in accordance with the digital broadcasting method. Note that the second error correction unit 72 may perform decoding processing in addition to correction processing.

[0174] The control unit 80 outputs a control signal to the DIL unit 60 specifying the memory areas 95B and 96B that the DIL unit 60 will use when performing deinterleaving processing. The first DIL unit 61 and the second DIL unit 62 each perform deinterleaving processing using the memory areas 95B and 96B based on this control signal.

[0175] For example, the first DIL unit 61 performs deinterleaving using the fifth memory area 95B corresponding to the first DIL unit 61. The second DIL unit 62 performs deinterleaving using the sixth memory area 96B corresponding to the second DIL unit 62.

[0176] Here, when the FFT size is 32k, let N be the amount of memory required in the DIL section for signal processing of the entire receiving bandwidth Bf for one system. Also, if the amount of memory allocated to one storage area in the first operating mode m1 is N / 2, then the amount of memory required for the two storage areas in this embodiment is 2 × N / 2 = N. Since the amount of memory required to process the signal of a partial receiving bandwidth Bp is approximately N / 4, the amount of memory processed in the first DIL section 61 and the second DIL section 62 is approximately N / 4. Therefore, the amount of memory N / 2 allocated to the DIL section 60 sufficiently covers the amount of memory required for data processing in the first operating mode m1.

[0177] In the second operating mode m2 shown in Figure 16B, the first DIL unit 61 of the DIL unit 60 processes signals in the entire receiving band Bf.

[0178] In the second operating mode m2, the first DIL unit 61 requires memory N for processing the digital signal across the entire reception bandwidth Bf. Therefore, the control unit 80 outputs a control signal to the DIL unit 60 instructing it to change the access destination for memory areas 95B and 96B. Based on the control signal output from the control unit 80, the first DIL unit 61 accesses not only the fifth memory area 95B but also other memory areas different from the fifth memory area 95B to perform deinterleaving processing. Specifically, the first DIL unit 61 uses all of the fifth memory area 95B and the sixth memory area 96B to perform deinterleaving processing. In this example, the amount of memory used by the first DIL unit 61 is 2 × N / 2 = N.

[0179] In this way, by changing how the DIL unit 60 shares each memory area 95B and 96B depending on the operating mode of the receiving device 1B, it is possible to suppress an increase in the amount of memory installed in the receiving device 1B. This makes it possible to provide a receiving device 1B that can receive next-generation digital broadcasts.

[0180] Next, we will describe other examples of the operating modes of the digital broadcast receiver 1B.

[0181] During the transition period from the current system to the next-generation system, it is expected that both systems will coexist, so it is desirable to be able to receive digital broadcasts of both systems during this transition period. The digital broadcast receiving device 1B according to Embodiment 3 is not limited to next-generation digital broadcasts, but can also receive digital broadcasts of the current system (ISDB-T).

[0182] Figure 16C shows the operating modes when receiving current digital broadcasts with the digital broadcasting receiver 1B. Figure 16C shows an example of receiving current broadcast signals using diversity reception.

[0183] In the current operating mode shown in Figure 16C, the DIL unit 60 processes a signal with an FFT size of 8k for the same physical channel (see Figure 1(a)). Specifically, the first DIL unit 61 and the second DIL unit 62 process the signal with an FFT size of 8k to output the deinterleaved signal.

[0184] The first DIL unit 61 processes using the fifth memory area 95B corresponding to the first DIL unit 61. The second DIL unit 62 processes using the sixth memory area 96B corresponding to the second DIL unit 62.

[0185] In the current operating mode, the amount of memory required to process a signal with an FFT size of 8k is N / 4. Therefore, the amount of memory required for the two memory areas is 2 × N / 4 = N / 2. According to this example, the amount of memory used in the current system can be N / 2. The receiving device 1B of this embodiment is also capable of receiving digital broadcasts using the current system.

[0186] [Modification 1 of Embodiment 3] Modification 1 of Embodiment 3 will be described with reference to Figures 17A to 17C. In this Modification 1, an example will be described in which the FFT size of the physical channels of the next-generation digital broadcasting system is 32k, 16k, or 8k. In this description, we will focus on the second operating mode m2.

[0187] Figure 17A shows the second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiver 1B is 32k.

[0188] In the operating mode shown in Figure 17A, the first DIL unit 61 of the DIL unit 60 processes signals in the entire reception band Bf. The first DIL unit 61 accesses not only the fifth memory area 95B but also other memory areas different from the fifth memory area 95B to perform deinterleaving processing. Specifically, the first DIL unit 61 uses both the fifth memory area 95B and the sixth memory area 96B to perform deinterleaving processing.

[0189] In this example, the amount of memory used in the first DIL section 61 is 2 × N / 2 = N. Therefore, when the FFT size of the physical channel is 32k, it is possible to suppress the increase in the amount of memory installed in the receiving device 1B.

[0190] Figure 17B shows the second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiver 1B is 16k. The figure also shows an example of diversity reception using two antennas 2a and 2c.

[0191] In the operating mode shown in Figure 17B, the first DIL unit 61 of the DIL unit 60 processes signals across the entire reception bandwidth Bf. The first DIL unit 61 and the second DIL unit 62 access the fifth memory area 95B and the sixth memory area 96B, respectively, to perform deinterleaving processing.

[0192] In this example, the amount of memory used in the first DIL section 61 is N / 2, the amount of memory used in the second DIL section 62 is N / 2, and the total amount of memory used is N. Therefore, when the FFT size of the physical channel is 16k, it is possible to suppress an increase in the amount of memory installed in the receiving device 1B.

[0193] Figure 17C shows the second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiver 1B is 8k. The figure also shows an example of diversity reception using four antennas 2a to 2d.

[0194] In the operating mode shown in Figure 17C, the DIL unit 60 processes signals across the entire reception bandwidth Bf. The first DIL unit 61 and the second DIL unit 62 access the fifth memory area 95B and the sixth memory area 96B, respectively, to perform deinterleaving processing.

[0195] In this example, the amount of memory used by the first DIL section 61 and the second DIL section 62 is N / 4, and the total amount of memory used is N / 2. Therefore, when the FFT size of the physical channel is 8k, it is possible to suppress the increase in the amount of memory installed in the receiving device 1B.

[0196] Furthermore, Modification 1 of this embodiment 3 can be applied to systems that do not have a partial reception bandwidth. For example, it can be applied to DVB-T2 (Digital Video Broadcasting-Terrestrial 2) and ATSC3.0 (Advanced Television Systems Committee 3.0), which have FFT sizes up to 32k, and systems similar to these, as long as the FFT size exceeds 8k. In addition, for systems like ATSC3.0 where the FFT size differs for each subframe, for example, if subframe #1 has an FFT size of 8k and subframe #2 has an FFT size of 32k, the system may operate in the operating mode shown in Figure 17C when receiving subframe #1, and in the operating mode shown in Figure 17A when receiving subframe #2.

[0197] (summary) The digital broadcast receiving device 1 of this embodiment is a digital broadcast receiving device that receives OFDM digital broadcasts. The physical channels of digital broadcasts have a partial reception band Bp, which is part of the reception band. The digital broadcast receiving device 1 comprises a plurality of demodulation units 30 that perform demodulation processing, and a combining unit 50 that combines the outputs of the plurality of demodulation units 30. In the first operating mode m1, the plurality of demodulation units 30 output a plurality of demodulated signals s1 by processing the signals of the partial reception band Bp of the same physical channel. The combining unit 50 processes the partial reception band Bp based on the plurality of demodulated signals s1 output from the plurality of demodulation units 30. In the second operating mode m2, which is different from the first operating mode m1, one of the plurality of demodulation units 30 (for example, demodulation unit 31) outputs a single demodulated signal s2 by processing the signals of the entire reception band Bf, which includes the partial reception band Bp. The combining unit 50 processes the entire reception band Bf based on the single demodulated signal s2 output from one demodulation unit 31.

[0198] In this way, by changing the demodulated signal output from the demodulation unit 30 and the synthesis process of the synthesis unit 50 based on the demodulated signal according to the operating mode of the receiving device 1, it is possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0199] Furthermore, the multiple demodulation units 30 include a first demodulation unit 31, a second demodulation unit 32, a third demodulation unit 33, and a fourth demodulation unit 34. One of the above demodulation units may be the first demodulation unit 31.

[0200] According to this, the demodulated signals output from the multiple demodulation units 30 and the demodulated signal output from the first demodulation unit 31 can be changed according to the operating mode of the receiving device 1, and furthermore, the synthesis process of the synthesis unit 50 based on the demodulated signals can be changed. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0201] Furthermore, in the first operating mode m1, the first demodulation unit 31 performs processing using the first memory area 91 corresponding to the first demodulation unit 31, the second demodulation unit 32 performs processing using the second memory area 92 corresponding to the second demodulation unit 32, the third demodulation unit 33 performs processing using the third memory area 93 corresponding to the third demodulation unit 33, and the fourth demodulation unit 34 performs processing using the fourth memory area 94 corresponding to the fourth demodulation unit 34. In the second operating mode m2, the first demodulation unit 31 may use the first memory area 91 as well as at least a portion of the second memory area 92, the third memory area 93, and the fourth memory area 94 to perform processing.

[0202] With this configuration, the way in which the demodulation unit 30 shares memory areas 91-94 can be changed depending on the operating mode of the receiving device 1. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0203] Furthermore, the signal of the partial reception band Bp processed in the first operating mode m1 is a signal based on digital broadcasts input from multiple antennas 2a to 2d, which correspond one-to-one with multiple demodulation units 30. The signal of the full reception band Bf processed in the second operating mode m2 may be a signal based on digital broadcasts input from one antenna 2a corresponding to one demodulation unit 31.

[0204] According to this, the way in which the demodulation unit 30 shares the memory areas 91 to 94 can be changed depending on whether the digital broadcast is received via multiple antennas 2a to 2d or via a single antenna 2a. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0205] Furthermore, each of the multiple demodulation units 30 includes a time-axis processing unit 41 that processes the time axis of a digital broadcast wave, an FFT processing unit 42 connected to the output side of the time-axis processing unit 41, a subcarrier synchronization unit 43 connected to the output side of the FFT processing unit 42, and a transmission path estimation unit 44 connected to the output side of the subcarrier synchronization unit 43. In the first operating mode m1, the multiple demodulation units 30 output multiple demodulated signals s1 using their respective time-axis processing units 41, FFT processing units 42, subcarrier synchronization unit 43, and transmission path estimation unit 44. In the second operating mode m2, one demodulation unit 31 may output one demodulated signal s2 using its own time-axis processing unit 41, FFT processing unit 42, subcarrier synchronization unit 43, and transmission path estimation unit 44.

[0206] This configuration allows the demodulated signal output from the demodulation unit 30 to be changed according to the operating mode of the receiving device 1. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0207] Furthermore, one demodulation unit 31 has a pre-combination unit 46 that is different from the combination unit 50. The pre-combination unit 46 combines the signal being processed by one demodulation unit 31 with the signal being processed by another demodulation unit different from the one demodulation unit 31 to generate a combined signal sp. In the second operating mode m2, one demodulation unit 31 may perform processing on the combined signal sp generated by the pre-combination unit 46.

[0208] This configuration allows the pre-combination unit 46 to generate a combined signal sp with suppressed noise. Therefore, the quality of signals processed in stages after the pre-combination unit 46 can be improved. This makes it possible to provide a receiving device 1 capable of receiving next-generation digital broadcasts.

[0209] Furthermore, the signal being processed by one demodulation unit 31 and the signal being processed by the other demodulation unit may be the same signal as the signal input to the time axis processing unit 41 or the signal input to the FFT processing unit 42.

[0210] This configuration allows the pre-combination unit 46 to appropriately generate a combined signal sp with suppressed noise. Therefore, the quality of signals processed in stages after the pre-combination unit 46 can be improved. This makes it possible to provide a receiving device 1 capable of receiving next-generation digital broadcasts.

[0211] Furthermore, one demodulation unit 31 has a selection unit 47 to which both the signal being processed by the demodulation unit 31 and the combined signal sp generated by the pre-combination unit 46 are input. In the first operating mode m1, the selection unit 47 selects the signal being processed by the demodulation unit 31, and the demodulation unit 31 continues to process the signal being processed by the demodulation unit 31. In the second operating mode m2, the selection unit 47 may select the combined signal sp, and the demodulation unit 31 may perform processing on the combined signal sp.

[0212] With this configuration, in the first operating mode m1, a signal being processed by one demodulation unit 31 can be selected, and in the second operating mode m2, a combined signal sp output from the pre-combination unit 46 can be selected. Therefore, the quality of signals processed after the pre-combination unit 46 can be improved as needed. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0213] Furthermore, if the broadcast wave of a digital broadcast includes parameters related to the FFT size, and the FFT size corresponds to 32k in the second operating mode m2, the combining unit 50 may perform processing on the entire reception band Bf based on only one demodulated signal output from one demodulation unit 31.

[0214] Furthermore, if the broadcast wave of a digital broadcast includes parameters related to the FFT size, and the FFT size corresponds to 16k in the second operating mode m2, the combining unit 50 may perform processing on the entire reception band Bf based on one demodulated signal output from the first demodulation unit 31 and a demodulated signal output from any one of the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34.

[0215] Furthermore, if the broadcast wave of a digital broadcast includes parameters related to the FFT size, and the FFT size corresponds to 8k in the second operating mode m2, the combining unit 50 may perform processing on the entire reception band Bf based on one demodulated signal output from the first demodulation unit 31 and the demodulated signals output from the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34, respectively.

[0216] Furthermore, the physical channel may consist of 35 segments with consecutive frequency bands, and the partial receiving band may be the 9 segments located in the middle of the 35 segments.

[0217] According to this, it is possible to provide a receiving device 1 that can receive digital broadcasts having physical channels composed of 35 segments.

[0218] The digital broadcast receiving device 1A of this embodiment is a digital broadcast receiving device that receives OFDM digital broadcasts. The physical channels of digital broadcasts have a partial reception band Bp which is part of the reception band and a non-partial reception band Bn which is different from the partial reception band Bp. The digital broadcast receiving device 1A includes a first demodulation unit 31 and a second demodulation unit 32 which perform demodulation processing, and a combining unit 51 which combines the output of the first demodulation unit 31 and the output of the second demodulation unit 32. The combining unit 51 processes signals in the partial reception band Bp based on the demodulated signal output from the first demodulation unit 31 and the demodulated signal output from the second demodulation unit 32, and processes signals in the non-partial reception band Bn based only on the demodulated signal output from the first demodulation unit 31.

[0219] In this way, by changing the demodulated signals output from the first demodulation unit 31 and the second demodulation unit 32, as well as the synthesis processing of the synthesis unit 51 based on the demodulated signals, depending on whether the processing corresponds to a signal in the partial reception band Bp or the non-partial reception band Bn, it is possible to provide a receiving device 1A that can receive next-generation digital broadcasts.

[0220] Furthermore, the first demodulation unit 31 has a pre-combination unit 46A that is different from the combination unit 51. The pre-combination unit 46A combines the signal being processed by the first demodulation unit 31 and the signal being processed by the second demodulation unit 32 to generate a combined signal sp. The first demodulation unit 31 may also perform processing on the combined signal sp generated by the pre-combination unit 46A.

[0221] This configuration allows the pre-combination unit 46A to generate a combined signal sp with suppressed noise. Therefore, the quality of signals processed in stages after the pre-combination unit 46A can be improved. This makes it possible to provide a receiving device 1A capable of receiving next-generation digital broadcasts.

[0222] Furthermore, each of the first demodulation unit 31 and the second demodulation unit 32 includes a time-axis processing unit 41 that performs time-axis processing of a digital broadcast wave, an FFT processing unit 42 connected to the output side of the time-axis processing unit 41, a subcarrier synchronization unit 43 connected to the output side of the FFT processing unit 42, and a transmission path estimation unit 44 connected to the output side of the subcarrier synchronization unit 43. The signal being processed by the first demodulation unit 31 and the signal being processed by the second demodulation unit 32 may be the same signal as the signal input to the time-axis processing unit 41 or the signal input to the FFT processing unit 42.

[0223] This configuration allows the pre-combination unit 46A to appropriately generate a combined signal sp with suppressed noise. Therefore, the quality of signals processed in stages after the pre-combination unit 46A can be improved. This makes it possible to provide a receiving device 1A capable of receiving next-generation digital broadcasts.

[0224] Furthermore, the broadcast waves of digital broadcasts include parameters related to the FFT size. The combining unit 51 has a first processing mode that is performed when the FFT size is 32k, and a second processing mode that is performed when the FFT size is 16k or 8k. In the first processing mode, the combining unit 51 processes signals in the partial reception band Bp based on the demodulated signal output from the first demodulator 31 and the demodulated signal output from the second demodulator 32, and processes signals in the non-partial reception band Bn based only on the demodulated signal output from the first demodulator 31. In the second processing mode, the combining unit 51 may process both signals in the partial reception band Bp and signals in the non-partial reception band Bn based on both the first demodulator 31 and the second demodulator 32.

[0225] The first processing mode described above is the processing mode shown in Figure 14A, and the second processing mode is the processing mode shown in Figure 14B or Figure 14C.

[0226] Furthermore, a physical channel may consist of 35 segments with consecutive frequency bands, the partial receiving band Bp may be the 9 segments located in the middle of the 35 segments, and the non-partial receiving band Bn may be the 26 segments excluding the partial receiving band Bp.

[0227] According to this, a receiving device 1A capable of receiving digital broadcasts having physical channels composed of 35 segments can be provided.

[0228] The digital broadcasting reception method of this embodiment is a method for receiving OFDM digital broadcasts. The physical channels of digital broadcasts have a partial reception band Bp, which is a part of the reception band. The digital broadcasting reception method selectively performs processing by a first operating mode m1 and processing by a second operating mode m2, which is different from the first operating mode m1. In the processing by the first operating mode m1, multiple demodulation units 30 output multiple demodulated signals s1 by processing the signals of the partial reception band Bp of the same physical channel, and the combining unit 50 performs processing on the partial reception band Bp based on the multiple demodulated signals s1. In the processing by the second operating mode m2, one demodulation unit (for example, demodulation unit 31) among the multiple demodulation units 30 outputs one demodulated signal s2 by processing the signals of the entire reception band Bf, which includes the partial reception band Bp, and the combining unit 50 performs processing on the entire reception band Bf based on the one demodulated signal s2.

[0229] In this way, by changing the demodulated signal output from the demodulation unit 30 and the synthesis process of the synthesis unit 50 based on the demodulated signal, depending on the operating mode when receiving digital broadcasts, it is possible to provide a reception method that can handle the reception of next-generation digital broadcasts.

[0230] The digital broadcasting reception method of this embodiment is a method for receiving OFDM digital broadcasts. The physical channels of digital broadcasts have a partial reception band Bp which is part of the reception band and a non-partial reception band Bn which is different from the partial reception band Bp. In the digital broadcasting reception method, as processing for signals in the partial reception band Bp, a synthesis process is performed based on the demodulated signal output from the first demodulation unit 31 and the demodulated signal output from the second demodulation unit 32, and as processing for signals in the non-partial reception band Bn, processing is performed based only on the demodulated signal output from the first demodulation unit 31.

[0231] In this way, by changing the demodulated signals output from the first demodulation unit 31 and the second demodulation unit 32, as well as the synthesis processing of the synthesis unit 51 based on the demodulated signals, depending on whether the processing corresponds to a signal in the partial reception band Bp or the non-partial reception band Bn, it is possible to provide a reception method that can handle the reception of next-generation digital broadcasts.

[0232] (Other embodiments) The digital broadcasting receiving device according to the embodiments of this disclosure has been described above based on embodiments, etc., but this disclosure is not limited to these embodiments. For example, other embodiments realized by arbitrarily combining the components described herein, or by excluding some of the components, may also be considered embodiments of this disclosure. Furthermore, modifications that can be obtained by applying various modifications to the above embodiments as conceived by a person skilled in the art, without departing from the spirit of this disclosure, that is, the meaning indicated by the wording in the claims, are also included in this disclosure.

[0233] Furthermore, the following forms may also be included within the scope of one or more aspects of this disclosure.

[0234] (1) Some of the components constituting the above-mentioned digital broadcast receiving device may be a computer system consisting of a microprocessor, ROM, RAM, hard disk unit, display unit, keyboard, mouse, etc. A computer program is stored in the RAM or hard disk unit. The microprocessor achieves its function by operating in accordance with the computer program. Here, the computer program is composed of a combination of multiple instruction codes that indicate commands to the computer in order to achieve a predetermined function.

[0235] (2) Some of the components constituting the digital broadcasting receiving device described above may be made up of a single system LSI (Large Scale Integration). The system LSI is a highly functional LSI manufactured by integrating multiple components onto a single chip, and specifically, it is a computer system that includes a microprocessor, ROM, RAM, etc. A computer program is stored in the RAM. The system LSI achieves its function by operating the microprocessor in accordance with the computer program.

[0236] (3) Some of the components constituting the digital broadcast receiving device described above may consist of detachable IC cards or standalone modules attached to each device. The IC card or module is a computer system consisting of a microprocessor, ROM, RAM, etc. The IC card or module may include the above-mentioned multi-functional LSI. The microprocessor operates according to a computer program, thereby enabling the IC card or module to perform its function. The IC card or module may be tamper-resistant.

[0237] (4) Furthermore, some of the components constituting the above-described digital broadcast receiving device may be the computer program or the digital signal recorded on a recording medium that can be read by a computer, such as a flexible disk, hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray® Disc), semiconductor memory, etc. Alternatively, the digital signal may be recorded on one of these recording media.

[0238] Furthermore, some of the components constituting the above-mentioned digital broadcasting receiving device may transmit the computer program or the digital signal via telecommunications lines, wireless or wired communication lines, networks such as the Internet, data broadcasting, etc.

[0239] (5) The disclosure may also be the methods described above. Alternatively, it may be a computer program that implements these methods using a computer, or a digital signal consisting of the computer program.

[0240] (6) The present disclosure also relates to a computer system comprising a microprocessor and memory, wherein the memory stores the computer program, and the microprocessor operates in accordance with the computer program.

[0241] (7) Alternatively, the program or the digital signal may be carried out by another independent computer system by recording it on the recording medium and transferring it, or by transferring the program or the digital signal via the network or the like.

[0242] (8) The above embodiments and the above modifications may be combined. [Industrial applicability]

[0243] The digital broadcasting receiving device described herein can be used as a broadcasting receiving device mounted on a mobile device such as a vehicle. [Explanation of Symbols]

[0244] 1, 1A, 1B Digital broadcasting receiving equipment (receiving equipment) 2a, 2b, 2c, 2d antennas 3. Video and audio output section 4 Input section 10, 11, 12, 13, 14 RF section 20, 21, 22, 23, 24 ADC section (AD conversion section) 30, 31, 32, 33, 34 Demodulation section 41 Time-axis processing unit 42 FFT Processing Unit 43 Subcarrier Synchronization Unit 44 Transmission path estimation unit 45 Equalization section 46, 46A Pre-composite section 47, 47A Selection Section 50, 51, 52 composite section 60, 61, 62 DIL section (Deinterleaved section) 70, 71, 72 Error correction section 80 Control Unit 90 Memory section 91, 91A, 92, 92A, 93, 94, 95B, 96B storage area Bf full receiving band Bp partial receiving band Bn Non-partial receiving band m1 First operating mode m2 Second operating mode s1, s2, s11, s12 Demodulated signals sc1, sc2, sp composite signal

Claims

1. A digital broadcasting receiver that receives digital broadcasts using the OFDM (Orthogonal Frequency Division Multiplexing) system, The physical channels of the aforementioned digital broadcast have a partial receiving bandwidth which is part of the receiving bandwidth. The aforementioned digital broadcast receiving device is It comprises a plurality of demodulation units that perform demodulation processing, and a combining unit that combines the outputs of the plurality of demodulation units, In the first operating mode, The multiple demodulation units output multiple demodulated signals by processing the signals of the partial receiving band of the same physical channel. The combining unit performs processing on the partial receiving band based on the multiple demodulated signals output from the multiple demodulation units. In a second operating mode different from the first operating mode, One of the multiple demodulation units outputs a single demodulated signal by processing the signal of the entire reception band, including the partial reception band. The combining unit performs processing on the entire receiving band based on the demodulated signal output from the demodulation unit. Digital broadcasting receiving device.

2. The plurality of demodulation units include a first demodulation unit, a second demodulation unit, a third demodulation unit, and a fourth demodulation unit. The aforementioned demodulation unit is the first demodulation unit. The digital broadcasting receiving device according to claim 1.

3. In the first operating mode described above, The first demodulation unit performs processing using the first memory area corresponding to the first demodulation unit. The second demodulation unit performs processing using the second memory area corresponding to the second demodulation unit. The third demodulation unit performs processing using the third memory area corresponding to the third demodulation unit. The fourth demodulation unit performs processing using the fourth memory area corresponding to the fourth demodulation unit. In the second operating mode described above, The first demodulation unit uses the first storage area and processes using at least a portion of the second, third, and fourth storage areas. The digital broadcasting receiving device according to claim 2.

4. The signal of the partial reception band processed in the first operating mode is a signal based on the digital broadcast input from a plurality of antennas that correspond one-to-one with the plurality of demodulation units. The signal of the entire reception band processed in the second operating mode is a signal based on the digital broadcast input from one antenna corresponding to one demodulation unit. A digital broadcasting receiving device according to any one of claims 1 to 3.

5. Each of the aforementioned multiple demodulators is: A time-axis processing unit that processes the time-axis of the broadcast wave of the aforementioned digital broadcast, The FFT processing unit is connected to the output side of the time axis processing unit, A subcarrier synchronization unit connected to the output side of the FFT processing unit, A transmission path estimation unit connected to the output side of the subcarrier synchronization unit, It has, In the first operating mode described above, Each of the aforementioned multiple demodulation units outputs the multiple demodulated signals using its respective time-axis processing unit, FFT processing unit, subcarrier synchronization unit, and transmission path estimation unit. In the second operating mode described above, The demodulation unit outputs the demodulated signal using the time axis processing unit, the FFT processing unit, the subcarrier synchronization unit, and the transmission path estimation unit of the demodulation unit. A digital broadcast receiving device according to any one of claims 1 to 3.

6. The aforementioned demodulation unit has a pre-synthesis unit different from the synthesis unit, The pre-combination unit combines the signal being processed in one demodulation unit with the signal being processed in another demodulation unit different from the one described above to generate a combined signal. In the second operating mode described above, The aforementioned demodulation unit performs processing on the synthesized signal generated by the pre-synthesis unit. The digital broadcasting receiving device according to claim 5.

7. The signal being processed by one demodulation unit and the signal being processed by the other demodulation unit are the same signals as the signal input to the time-axis processing unit or the signal input to the FFT processing unit. The digital broadcasting receiving device according to claim 6.

8. The aforementioned demodulation unit further includes a selection unit to which both the signal being processed by the demodulation unit and the combined signal generated by the pre-combination unit are input. In the first operating mode described above, The selection unit selects the signal being processed by the demodulation unit, The aforementioned demodulation unit continues to process the signal being processed by the demodulation unit, In the second operating mode described above, The selection unit selects the composite signal, The aforementioned demodulation unit performs processing on the composite signal. The digital broadcasting receiving device according to claim 6.

9. The aforementioned digital broadcasting transmission method includes parameters related to the FFT size, In the second operating mode described above, if the FFT size corresponds to 32k, The combining unit performs processing on the entire receiving band based solely on the single demodulated signal output from the single demodulation unit. A digital broadcast receiving device according to claim 2 or 3.

10. The aforementioned digital broadcasting transmission method includes parameters related to the FFT size, In the second operating mode described above, if the FFT size corresponds to 16k, The combining unit performs processing on the entire receiving band based on the one demodulated signal output from the first demodulation unit and the demodulated signal output from any one of the second, third, and fourth demodulation units. A digital broadcast receiving device according to claim 2 or 3.

11. The aforementioned digital broadcasting transmission method includes parameters related to the FFT size, In the second operating mode described above, if the FFT size is 8k compatible, The combining unit performs processing on the entire receiving band based on the one demodulated signal output from the first demodulation unit and the demodulated signals output from the second demodulation unit, the third demodulation unit, and the fourth demodulation unit, respectively. A digital broadcast receiving device according to claim 2 or 3.

12. The physical channel is composed of 35 segments with continuous frequency bands. The aforementioned partial receiving band consists of nine segments located in the center of the 35 segments. A digital broadcast receiving device according to any one of claims 1 to 3.

13. A digital broadcasting receiver that receives digital broadcasts using the OFDM (Orthogonal Frequency Division Multiplexing) system, The physical channels of the aforementioned digital broadcast have a partial reception band which is part of the reception band and a non-partial reception band which is different from the partial reception band. The aforementioned digital broadcast receiving device is A first demodulation unit and a second demodulation unit that perform demodulation processing, A combining unit that combines the output of the first demodulation unit and the output of the second demodulation unit, Equipped with, The aforementioned synthesis section is As processing corresponding to the signal in the aforementioned partial receiving band, processing is performed based on the demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit. As processing for signals in the non-partial reception band, processing is performed based only on the demodulated signal output from the first demodulation unit. Digital broadcasting receiving device.

14. The first demodulation unit has a pre-synthesis unit different from the synthesis unit, The pre-combination unit combines the signal being processed in the first demodulation unit and the signal being processed in the second demodulation unit to generate a combined signal. The first demodulation unit performs processing on the synthesized signal generated by the pre-synthesis unit. The digital broadcasting receiving device according to claim 13.

15. Each of the first demodulation unit and the second demodulation unit is: A time-axis processing unit that processes the time-axis of the broadcast wave of the aforementioned digital broadcast, The FFT processing unit is connected to the output side of the time axis processing unit, A subcarrier synchronization unit connected to the output side of the FFT processing unit, A transmission path estimation unit connected to the output side of the subcarrier synchronization unit, It has, The signal being processed in the first demodulation unit and the signal being processed in the second demodulation unit are the same signals as the signal input to the time axis processing unit or the signal input to the FFT processing unit. The digital broadcasting receiving device according to claim 14.

16. The aforementioned digital broadcasting transmission method includes parameters related to the FFT size, The aforementioned synthesis section is The system has a first processing mode performed when the FFT size is 32k compatible, and a second processing mode performed when the FFT size is 16k compatible or 8k compatible. In the first processing mode, as processing for signals in the partial reception band, processing is performed based on the demodulated signal output from the first demodulator and the demodulated signal output from the second demodulator, and as processing for signals in the non-partial reception band, processing is performed based only on the demodulated signal output from the first demodulator. In the second processing mode, processing is performed with respect to both the signal in the partial reception band and the signal in the non-partial reception band based on both the first demodulation unit and the second demodulation unit. A digital broadcast receiving device according to any one of claims 13 to 15.

17. The physical channel is composed of 35 segments with continuous frequency bands. The aforementioned partial receiving band consists of nine segments located in the center of the 35 segments. The non-partial reception band consists of 26 segments excluding the partial reception band. A digital broadcast receiving device according to any one of claims 13 to 15.

18. A digital broadcasting reception method for receiving digital broadcasts using the OFDM (Orthogonal Frequency Division Multiplexing) system, The physical channels of the aforementioned digital broadcast have a partial receiving bandwidth which is part of the receiving bandwidth. In the digital broadcasting reception method described above, processing by a first operating mode and processing by a second operating mode different from the first operating mode are performed selectively. In the processing according to the first operating mode described above, Multiple demodulation units process the signals of the partial receiving band of the same physical channel to output multiple demodulated signals, and a combining unit performs processing on the partial receiving band based on the multiple demodulated signals. In the processing according to the second operating mode described above, One of the multiple demodulation units processes the signals of the entire reception band, including the partial reception band, to output a single demodulated signal, and the combining unit performs processing on the entire reception band based on the single demodulated signal. Digital broadcasting reception methods.

19. A digital broadcasting reception method for receiving digital broadcasts using the OFDM (Orthogonal Frequency Division Multiplexing) system, The physical channels of the aforementioned digital broadcast have a partial reception band which is part of the reception band and a non-partial reception band which is different from the partial reception band. In the aforementioned digital broadcasting reception method, As processing corresponding to the signal in the aforementioned partial receiving band, a synthesis process is performed based on the demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit. As processing for signals in the non-partial reception band, processing is performed based only on the demodulated signal output from the first demodulation unit. Digital broadcasting reception methods.

20. A digital broadcasting receiving device for receiving digital broadcasts using the OFDM (Orthogonal Frequency Division Multiplexing) system, The aforementioned digital broadcasting transmission method has a frame structure, where one frame consists of multiple subframes, and each of the multiple subframes includes parameters related to the FFT size. The digital broadcast receiving device comprises a plurality of demodulation units that perform demodulation processing, and a combining unit that combines the outputs of the plurality of demodulation units. The first demodulator, which is one of the plurality of demodulators, processes the digital broadcast signal to output a single demodulated signal. The combining unit performs processing on the digital broadcast signal based on at least one demodulated signal output from the first demodulation unit. If the FFT size in one of the aforementioned subframes corresponds to 32k, The combining unit processes the digital broadcast signal based solely on the single demodulated signal output from the single demodulated unit. If the FFT size in one of the aforementioned subframes corresponds to 16k or 8k, The combining unit performs processing on the digital broadcast signal based on at least two or more demodulated signals output from the plurality of demodulation units. Digital broadcasting receiving device.

21. The plurality of demodulation units include, in addition to the first demodulation unit, a second demodulation unit, a third demodulation unit, a fourth demodulation unit, If the FFT size in one of the aforementioned subframes is 8k compatible, The combining unit processes the digital broadcast signal based on the one demodulated signal output from the first demodulation unit and the demodulated signals output from the second demodulation unit, the third demodulation unit, and the fourth demodulation unit, respectively. If the FFT size in one of the aforementioned subframes corresponds to 16k, The combining unit processes the digital broadcast signal based only on the one demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit. The digital broadcasting receiving device according to claim 20.

22. Each of the plurality of demodulation units has a physically different memory area from each other, The first demodulation unit has a first memory area, The second demodulation unit has a second memory area, The third demodulation unit has a third memory area, The fourth demodulation unit has a fourth memory area, If the FFT size in one of the subframes corresponds to 8k, the first demodulator uses the first memory area, the second demodulator uses the second memory area, the third demodulator uses the third memory area, and the fourth demodulator uses the fourth memory area to perform processing on the digital broadcast signal. If the FFT size in one of the subframes corresponds to 32k, the first demodulation unit processes the digital broadcast signal using the second, third, and fourth storage areas in addition to the first storage area. The digital broadcasting receiving device according to claim 21.

23. Each of the plurality of demodulation units has a physically different memory area from each other. The first demodulation unit has a first memory area, The second demodulation unit has a second memory area, The third demodulation unit has a third memory area, The fourth demodulation unit has a fourth memory area, If the FFT size in one of the subframes corresponds to 8k, the first demodulator uses the first memory area, the second demodulator uses the second memory area, the third demodulator uses the third memory area, and the fourth demodulator uses the fourth memory area to perform processing on the digital broadcast signal. If the FFT size in one of the subframes corresponds to 16k, the first demodulation unit uses the third storage area in addition to the first storage area, and the second demodulation unit uses the fourth storage area in addition to the second storage area to process the digital broadcast signal. The digital broadcasting receiving device according to claim 21.

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