Digital broadcast receiver apparatus and digital broadcast reception 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

Digital broadcast receiving device and digital broadcast receiving method

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

[0002] The practical application of next-generation digital broadcasting is currently under consideration. This next-generation system is expected to employ a transmission method using Orthogonal Frequency Division Multiplexing (OFDM), the same as the current system (ISDB-T: Integrated Services Digital Broadcasting-Terrestrial).

[0003] Meanwhile, a technology for receiving digital broadcasts using diversity reception to ensure the quality of received signals is known for in-vehicle receivers. Patent Document 1 discloses an in-vehicle receiver that receives digital broadcasts using diversity reception, as an example of this type of receiver. In this receiver, the same channel is selected and demodulated in each of four reception branches, and the four demodulated signals are carrier-combined to generate viewing data.

[0004] Japanese Patent Application Laid-Open No. 2016-149651

[0005] In next-generation digital broadcasting, it is expected that the amount of data processed will increase compared to current systems in order to improve transmission rates. Therefore, if the technology disclosed in Patent Document 1 is applied to receiving next-generation digital broadcasting, memory for data processing will be used 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] An object of the present disclosure is to provide a digital broadcast receiving device and the like that is capable of receiving next-generation digital broadcasts.

[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 channel of the digital broadcast has a partial reception band that is a part of the reception band, and the digital broadcast receiving device is equipped with a plurality of demodulation units that perform demodulation processing and a synthesis unit that synthesizes 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 signals of the partial reception band of the same physical channel, and the synthesis unit performs processing on the partial reception band based on the plurality of demodulation 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 signals of the entire reception band including the partial reception band, and the synthesis unit performs processing on the entire reception band based on the single demodulation signal output from the single 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 channel of the digital broadcast has a partial reception band that is part of the reception band and a non-partial reception band that is different from the partial reception band, and the digital broadcast receiving device is equipped with a first demodulation unit and a second demodulation unit that perform demodulation processing, and a synthesis unit that synthesizes the output of the first demodulation unit and the output of the second demodulation unit, and the synthesis unit performs processing corresponding to signals in the partial reception band based on the demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit, and performs processing corresponding to signals in the non-partial reception band based only on the demodulated signal output from the first demodulation unit.

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

[0010] A digital broadcast receiving method in one embodiment of the present disclosure is a digital broadcast receiving method for receiving OFDM digital broadcasts, wherein a physical channel of the digital broadcast has a partial reception band that is part of the reception band and a non-partial reception band that is different from the partial reception band, and in the digital broadcast receiving method, as processing corresponding to signals in the partial reception band, a synthesis process is performed based on a demodulated signal output from a first demodulation unit and a demodulated signal output from a second demodulation unit, and as processing corresponding to signals in the non-partial reception band, a process is performed based only on the demodulated signal output from the first demodulation unit.

[0011] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0012] According to the present disclosure, it is possible to provide a digital broadcast receiving device and the like that is capable of receiving next-generation digital broadcasts.

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

[0014] (Background to the Invention of the Present Disclosure) The background to the invention of the present disclosure will be described with reference to FIG.

[0015] FIG. 1 is a diagram showing a schematic diagram of the physical channel structure of digital broadcasting in the current system and the next-generation system.

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

[0017] The FFT size of a physical channel in the current system is 8k (8,192 points: number of subcarriers = 5,617). The FFT size is the number of samples when FFT (Fast Fourier transform) processing is performed on a broadcast signal. FFT processing is an example of digital signal processing performed by a digital broadcast receiving device. The amount of memory required for demodulation processing in a digital broadcast receiving device increases in proportion 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 physical channel of the next-generation system is composed of 35 consecutive frequency band segments. This physical channel has a bandwidth of 5.83 MHz. The bandwidth of the central 9 segments of the 35 segments is 1.50 MHz. These 9 segments are partial reception bands and can include a layer equivalent to layer A of the current system. It is thought that in-vehicle digital broadcasting will be distributed using a layer consisting of up to 9 segments.

[0019] The FFT size of the physical channel in the next-generation digital broadcasting system can be three sizes: 8k (8,192 points), 16k (16,384 points), and 32k (32,768 points). While the current system has a maximum FFT size of 8k (8,192 points: number of subcarriers = 5,617), the next-generation system will have a maximum FFT size of 32k (32,768 points: number of subcarriers = 30,241). Thus, the next-generation system's FFT size is four times that of the current system, and the number of transmitted subcarriers will also be nearly four times that of the current system. Therefore, if conventional diversity reception technology is applied directly to the next-generation system, the increased FFT size will require a digital broadcast receiving device to be equipped with approximately four times the memory capacity of the previous system (4M: M represents the memory capacity required for the previous system (when the FFT size is 8k)), resulting in increased costs.

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

[0021] Hereinafter, embodiments will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in an independent claim showing an implementation form of one aspect of the present disclosure will be described as optional components. Implementation forms of the present disclosure are not limited to the current independent claim, but may also be expressed by other independent claims.

[0022] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and duplicated explanations may be omitted or simplified.

[0023] (First Embodiment) [Configuration of Digital Broadcast Receiving Apparatus] The configuration of a digital broadcast receiving apparatus according to a first embodiment will be described with reference to FIGS. 2 and 3. FIG.

[0024] FIG. 2 is a diagram showing the configuration of the digital broadcast receiving device 1 according to the first embodiment.

[0025] The digital broadcast receiving device 1 is a device for receiving OFDM digital broadcasts, and is mounted on a mobile object such as a vehicle. Hereinafter, the digital broadcast receiving device 1 may be referred to as the receiving device 1.

[0026] As shown in Fig. 2, the receiving device 1 includes an RF unit (tuner unit) 10, an ADC unit (AD conversion unit) 20, a demodulation unit 30, a synthesis unit 50, a DIL unit (deinterleave unit) 60, an error correction unit 70, and a control unit 80. Fig. 2 also shows a video / audio output unit 3 that outputs video and audio, and an input unit 4 that accepts operational input from a user. Fig. 2 also shows multiple antennas 2a, 2b, 2c, and 2d connected to the receiving device 1. The 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, the ADC unit 20, the demodulation unit 30, the combining unit 50, the DIL unit 60, and the 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 of the memory areas 91 to 94 stores data for digital signal processing during operation of the receiving device 1. While the memory unit 90 is included in the control unit 80, it may be located anywhere on a chip including the demodulation unit 30 and the DIL unit 60. The memory unit 90 may be configured as a single memory macro or multiple memory macros located in different locations on the chip. The control unit 80 may also include a memory unit other than the memory unit 90. How the demodulation unit 30 shares the memory areas 91 to 94 will be described later.

[0028] The input unit 4 is a device that accepts operational inputs from a user who uses the receiving device 1. The operational inputs accepted by the user include, for example, a channel selection input for selecting one physical channel from multiple physical channels. Furthermore, the operational inputs accepted by the user include a band selection input for selecting either a portion of the band or all of the bands of one physical channel. For example, the portion of the bands is selected when receiving digital broadcasts from a mobile object, and the entire bands is selected when receiving digital broadcasts from a stationary building or the like.

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

[0030] In this embodiment, the operation of the receiving device 1 is changed depending on the band selection input received by the input unit 4. That is, the input unit 4 receives an input to select a signal in a partial reception band Bp, which is a segment of a physical channel, or receives an input to select a full reception band Bf, which is all segments. The input unit 4 then outputs the operation input received from the user to the control unit 80. The control unit 80 performs processing on the broadcast signal input from the antenna based on the operation input received by the input unit 4.

[0031] Broadcast signals such as digital broadcasts are input to the multiple antennas 2a to 2d. The multiple antennas 2a to 2d are antennas for diversity reception. In a reception method using diversity reception, for example, the quality of the received signals can be improved by preferentially using a signal input from an antenna with better radio wave conditions among the multiple antennas, or by combining signals received by the multiple antennas to suppress noise. The digital broadcast signals input to each of the antennas 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 a digital broadcast signal output from an antenna to generate an analog signal of a predetermined frequency band. For example, the RF unit 10 selects a reception band to be processed based on a band selection signal output from the control unit 80, and converts the RF signal of the selected reception band in a desired physical channel into an intermediate frequency (IF) 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 digitally converted 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 a band selection signal and control signals (including various setting signals) output from the control unit 80.

[0035] Fig. 3 is a diagram showing the configuration of the demodulation unit 30 of the digital broadcast receiving device 1. Although Fig. 3 shows the first demodulation unit 31 as an example, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 also have the same configuration as the first demodulation unit 31.

[0036] 3, the demodulation unit 30 includes a time axis processing unit 41 that performs time axis processing of the digital broadcasting waves, 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 channel estimation unit 44 connected to the output side of the subcarrier synchronization unit 43. The demodulation unit 30 also includes an equalization unit 45 connected to the output sides of the subcarrier synchronization unit 43 and the transmission channel estimation unit 44.

[0037] The time axis processing unit 41 converts the IF signal into a baseband signal by orthogonally transforming it based on the signal output from the ADC unit 20, and further performs timing synchronization (symbol synchronization) of the OFDM symbols. The time axis processing unit 41 requires a memory capacity in symbol units for processing to perform timing synchronization of the OFDM symbols. The signal processed by the time axis processing unit 41 is output to the FFT processing unit 42.

[0038] The output signal from the RF unit 10 may be a baseband signal instead of an IF signal. In this case, orthogonal transform processing in the time axis processing unit 41 is not necessary. Hereinafter, in this embodiment and other embodiments, only IF signals will be described, but all relevant parts may be replaced with baseband signals, and processing equivalent to the processing in the time axis processing unit 41 will be interpreted appropriately.

[0039] The FFT processing unit 42 performs FFT processing on the signal output from the time axis processing unit 41 to convert it into a frequency axis signal. The FFT processing unit 42 requires a memory capacity according to the FFT size to perform FFT processing 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 capacity according 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 channel estimator 44 interpolates the transmission channel characteristics of the scattered pilot signals in the symbol / subcarrier direction. To perform this interpolation process, the transmission channel estimator 44 requires a memory capacity corresponding to a number of symbols according to the FFT size. The signal interpolated by the transmission channel estimator 44 is output to the equalizer 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 channel estimation unit 44, and outputs the corrected signal to the combiner 50. Note that the equalization unit 45 does not necessarily have to be provided in the demodulator 30, and may be provided in the combiner 50 at a subsequent stage. The equalization processing by the equalization unit 45 may be performed together with the combining in the combiner 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 combiner 50. Specifically, as shown in FIG. 2 , the first demodulation unit 31 demodulates the signal output from the first ADC unit 21 and outputs the demodulated signal to the combiner 50. The second demodulation unit 32 demodulates the signal output from the second ADC unit 22 and outputs the demodulated signal to the combiner 50. The third demodulation unit 33 demodulates the signal output from the third ADC unit 23 and outputs the demodulated signal to the combiner 50. The fourth demodulation unit 34 demodulates the signal output from the fourth ADC unit 24 and outputs the demodulated signal to the combiner 50.

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

[0045] The first combiner 51 combines one or more demodulated signals output from the demodulator 30 to generate a combined signal sc1. Note that the combining process of the combiner 50 in this embodiment includes not only a process for generating a combined signal based on multiple demodulated signals, but also a process for generating a combined signal based on a single demodulated signal. The first combiner 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 in accordance with the digital broadcasting system on the combined signal sc1 output from the first combiner 51. The signal processed by the first DIL unit 61 is output to a first error correction unit 71.

[0047] The first error correction unit 71 performs correction processing on the signal output from the first DIL unit 61 in accordance with the digital broadcasting standard, thereby generating a TS (Transport Stream) signal or a TLV (Type Length Value) signal (hereinafter referred to as the TS signal). The TS signal generated by the first error correction unit 71 is output to the video / audio output unit 3. The video / audio output unit 3 performs decoding processing on the TS signal. The video / 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 combiner 52 generates a combined signal sc2 by combining one or more demodulated signals output from the demodulator 30. The second combiner 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 in accordance with the digital broadcasting system on the combined signal sc2 output from the second combiner 52. The signal processed by the second DIL unit 62 is output to a second error correction unit 72.

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

[0051] [Operation of Digital Broadcast Receiving Device] The operation of the digital broadcast receiving device 1 will be described with reference to Figures 4A to 4C. In this example, the method of sharing each of the storage areas 91 to 94 by the demodulation unit 30 will be described. The following description will focus on the scene where the demodulation unit 30 outputs a demodulated signal to the first combiner 51.

[0052] Fig. 4A is a diagram showing a first operating mode m1 of the digital broadcast receiving device 1. Fig. 4B is a diagram showing a second operating mode m2 of the digital broadcast receiving device 1. The dashed arrows in Fig. 4A and Fig. 4B represent signal lines for reading and writing data (the same applies below).

[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 referred to as a first operating mode m1, and the operating mode for processing signals in the full reception band Bf including the partial reception band Bp is referred to as a 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 a plurality of antennas 2a to 2d that correspond one-to-one to a plurality of 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 one antenna 2a that corresponds to the first demodulation unit 31.

[0055] The control unit 80 switches the operation of the receiving device 1 between the first operation mode m1 and the second operation mode m2 based on the band selection input received by the input unit 4 .

[0056] 4A, the demodulators 30 process signals in the partial reception band Bp of the same physical channel to output demodulated signals s1. Specifically, the first demodulator 31, the second demodulator 32, the third demodulator 33, and the fourth demodulator 34 process signals in the partial reception band Bp to output demodulated signals s1.

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

[0058] Furthermore, the control unit 80 outputs a control signal to the demodulation unit 30, which specifies the storage areas 91 to 94 to be used when the demodulation unit 30 performs the demodulation process. The first demodulation unit 31, the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34 each perform the demodulation process using the storage areas 91 to 94 based on the control signal.

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

[0060] In the first operating mode m1, the memory capacity allocated to one storage area is the memory capacity required for processing nine segments of digital signals. If the memory capacity allocated to one storage area is M / 4, the memory capacity required for four storage areas is 4 × M / 4 = M.

[0061] 4B, the first demodulator 31 of the demodulators 30 processes signals in the entire reception band Bf to output a single demodulated signal s2. That is, the first demodulator 31 processes signals in all segments to output a single demodulated signal s2.

[0062] The first combiner 51 performs processing for the entire reception band Bf based on the demodulated signal s2 output from the first demodulator 31.

[0063] In the second operating mode m2, the first demodulation unit 31 requires a memory capacity necessary for digital signal processing of 35 segments. Therefore, the control unit 80 outputs a control signal to the demodulation unit 30 instructing it to change the access destination to the storage 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 storage area 91 but also other storage areas different from the first storage area 91 to perform demodulation processing. 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. In this example, the memory capacity used by the first demodulation unit 31 is 4×M / 4=M. This enables the first demodulation unit 31 to process digital signals of 35 segments.

[0064] In this way, by changing the way the demodulation unit 30 shares each of the storage areas 91 to 94 depending on the operation mode of the receiving device 1, it is possible to prevent an increase in the amount of memory required 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 the operation modes of the digital broadcast receiving device 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 the first embodiment is not limited to receiving digital broadcasts of the next-generation system, but is also capable of receiving digital broadcasts of the current system (ISDB-T).

[0067] Fig. 4C is a diagram showing an operation mode when receiving digital broadcasts of the current standard by the digital broadcast receiving device 1. Fig. 4C shows an example of receiving broadcast signals of the current standard by diversity reception.

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

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

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

[0071] [Digital Broadcast Receiving Method] FIG. 5 is a flowchart of a digital broadcast receiving method according to the first embodiment.

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

[0073] When the control unit 80 determines that the digital broadcasting is to be received in the current format, it outputs control signals to the RF unit 10, the demodulation unit 30, the DIL unit 60, and the error correction unit 70 so as to receive the digital broadcasting in the current format. In the receiving device 1, signal processing of the digital broadcasting in the current format is performed (step S11).

[0074] On the other hand, if the control unit 80 determines that digital broadcasting will be received using the next-generation standard, it proceeds to the next step and determines whether to receive signals in 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 via the input unit 4. Note that step S20 may be executed simultaneously with step S10.

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

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

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

[0078] When generating one demodulated signal s2, one demodulation unit 31 performs demodulation processing by accessing not only the first storage area 91 but also another storage area different from the first storage area 91. Specifically, one demodulation unit 31 performs demodulation processing by using all of the first storage area 91, the second storage area 92, the third storage area 93, and the fourth storage area 94.

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

[0080] [First Modification of First Embodiment] A first modification of the first embodiment will be described with reference to Figures 6 to 7B. In this first modification, an example will be described in which the receiving device 1 includes a pre-synthesizing unit 46 and a selecting unit 47.

[0081] FIG. 6 is a diagram showing the configuration of a digital broadcast receiving device 1 according to a first modification of the first embodiment.

[0082] The receiving device 1 of the first modification 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, the ADC unit 20, the demodulation unit 30, the combining unit 50, the DIL unit 60, the error correction unit 70, and the control unit 80 are the same as those in the first embodiment.

[0083] In the receiving device 1 of the first modification, the first demodulation unit 31 has a pre-synthesis unit 46 different from the synthesis unit 50, and a selection unit 47. Although not shown in Fig. 6, the first demodulation unit 31 of the first modification has the same functional blocks as the demodulation unit shown in Fig. 3.

[0084] The pre-synthesizer 46 generates a synthesized signal sp by synthesizing a signal being processed by the first demodulator 31 and a signal being processed by another demodulator (e.g., the second demodulator 32) different from the first demodulator 31. The synthesized signal sp generated by the pre-synthesizer 46 is output to the selector 47.

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

[0086] The selector 47 receives both the signal being processed by the first demodulator 31 and the combined signal sp output from the pre-combiner 46. The selector 47 selects either the signal being processed by the first demodulator 31 or the combined signal sp output from the pre-combiner 46. Which signal the selector 47 selects is determined by the operating mode of the receiver 1.

[0087] 7A is a diagram showing a first operation mode m1 of the digital broadcast receiving device 1 according to Modification 1. FIG. 7B is a diagram showing a second operation mode m2 of the digital broadcast receiving device 1 according to Modification 1.

[0088] The signals of the partial reception band Bp processed in the first operation mode m1 are signals based on digital broadcasts input from the multiple antennas 2a to 2d that correspond one-to-one to the multiple demodulators 30. The signals of the full reception band Bf processed in the second operation mode m2 are signals based on digital broadcasts input from the two antennas 2a and 2b that correspond to the first demodulator 31 and the second demodulator 32.

[0089] 7A, in the first operation mode m1, the selection unit 47 selects the signal being processed by the first demodulation unit 31. Then, the first demodulation unit 31 continues processing the signal being processed by the first demodulation unit 31. The way in which the demodulation unit 30 shares each of the storage areas 91 to 94 is the same as in the first operation mode m1 of the first embodiment.

[0090] 7B, in the second operating mode m2, the selector 47 selects the combined signal sp output from the pre-combiner 46. The first demodulator 31 then processes this combined signal sp. The method of sharing the storage areas 91 to 94 by the demodulator 30 is the same as in the second operating mode m2 of the first embodiment.

[0091] For example, in the second operating mode m2 of the first embodiment, signals of the entire reception band Bf are received using a single antenna 2a, which tends to degrade the quality of the received broadcast signal. In contrast, in the first modification, broadcast signals received by two antennas 2a and 2b are combined, allowing the pre-combiner 46 to generate a combined signal sp with reduced noise. In the second operating mode m2, the selector 47 selects the combined signal sp output from the pre-combiner 46, and the first demodulator 31 processes the selected combined signal sp. According to the first modification, the quality of signals processed at stages subsequent to the pre-combiner 46 can be improved.

[0092] [Variation 2 of Embodiment 1] Variation 2 of Embodiment 1 will be described with reference to Figures 8A to 8C. Variation 2 describes an example in which the FFT size of the physical channel of next-generation digital broadcasting is 32k, 16k, or 8k. Note that the description here focuses on the second operating mode m2.

[0093] FIG. 8A is a diagram showing the second operation mode m2 when the FFT size of the physical channel processed by the digital broadcast receiving device 1 is 32k.

[0094] 8A , a first demodulation unit 31 of the plurality of demodulation units 30 processes signals in the entire reception band Bf to output one demodulated signal. The first demodulation unit 31 performs demodulation processing by accessing not only the first storage area 91 but also another storage area different from the first storage area 91. Specifically, the first demodulation unit 31 performs demodulation processing by 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] According to this example, the memory size used by the first demodulator 31 is 4×M / 4=M. Therefore, even when the FFT size of the physical channel is 32k, an increase in the memory size installed in the receiving device 1 can be suppressed.

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

[0097] 8B , the first demodulator 31 and the third demodulator 33 of the multiple demodulators 30 process signals in the entire reception band Bf to output two demodulated signals. The first demodulator 31 and the third demodulator 33 access not only the first storage area 91 and the third storage area 93 but also other storage areas different from the first storage area 91 and the third storage area 93 to perform demodulation processing. Specifically, the first demodulator 31 performs demodulation processing using the first storage area 91 and the second storage area 92. The third demodulator 33 performs demodulation processing using the third storage area 93 and the fourth storage area 94.

[0098] According to this example, the memory capacity used by the first demodulator 31 is 2×M / 4=M / 2, the memory capacity used by the third demodulator 33 is 2×M / 4=M / 2, and the total memory capacity used is M. Therefore, even when the FFT size of the physical channel is 16k, it is possible to prevent the memory capacity to be installed in the receiving device 1 from increasing.

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

[0100] 8C , the multiple demodulators 30 process signals in the entire reception band Bf to output four demodulated signals. The first demodulator 31, the second demodulator 32, the third demodulator 33, and the fourth demodulator 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 demodulator 31 uses the first memory area 91, the second demodulator 32 uses the second memory area 92, the third demodulator 33 uses the third memory area 93, and the fourth demodulator 34 uses the fourth memory area 94 to perform demodulation processing.

[0101] According to this example, the memory capacity used by each demodulation unit 30 is M / 4, and the total memory capacity used is M. Therefore, even when the FFT size of the physical channel is 8k, it is possible to prevent the memory capacity to be installed in the receiving device 1 from increasing.

[0102] Note that Modification 2 of the first embodiment can be applied even to systems that do not have a partial reception band. For example, it may be applied to DVB-T2 (Digital Video Broadcasting-Terrestrial 2) and ATSC3.0 (Advanced Television Systems Committee 3.0), in which the FFT size is up to 32k, or systems similar to these systems, and any system in which the FFT size exceeds 8k may be used. Furthermore, in a system in which the FFT size differs for each subframe, such as ATSC3.0, for example, if the FFT size of subframe #1 is 8k and the FFT size of subframe #2 is 32k, the system may operate in the operating mode of Figure 8C when receiving subframe #1 and in the operating mode of Figure 8A when receiving subframe #2.

[0103] (Embodiment 2) [Configuration of Digital Broadcast Receiving Device] The configuration of a digital broadcast receiving device 1A according to embodiment 2 will be described with reference to Fig. 9. In this example, the partial reception band Bp and non-partial reception band Bn are received via antenna 2a, and the partial reception band Bp is received via antenna 2b.

[0104] The signals in the partial reception band Bp are signals based on digital broadcasts input from a plurality of antennas 2a, 2b that correspond one-to-one to the first demodulator 31 and the second demodulator 32. The signals in the non-partial reception band Bn are signals based on digital broadcasts input from one antenna 2a that corresponds to the first demodulator 31.

[0105] FIG. 9 is a diagram showing the configuration of a digital broadcast receiving device 1A according to the second embodiment.

[0106] The digital broadcast receiving device 1A is a device for receiving OFDM digital broadcasts, and is mounted on a mobile object such as a vehicle. Hereinafter, the digital broadcast receiving device 1A may be referred to as the receiving device 1A.

[0107] As shown in Fig. 9, the receiving device 1A includes an RF unit 10, an ADC unit 20, a demodulation unit 30, a synthesis unit 51, a DIL unit 61, an error correction unit 71, and a control unit 80. Fig. 9 also shows a video / audio output unit 3 that outputs video and audio, and an input unit 4 that accepts operational input from a user. Fig. 9 also shows multiple antennas 2a and 2b connected to the receiving device 1A. The 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, the ADC unit 20, the demodulation unit 30, the synthesis unit 51, the DIL unit 61, and the error correction unit 71. The control unit 80 includes a memory unit 90. The memory unit 90 has a first memory area 91A and a second memory area 92A. The memory capacity of the first memory area 91A is larger than the memory capacity of the second memory area 92A. Each of the memory areas 91A, 92A holds data for performing digital signal processing during operation of the receiving device 1A. How the demodulation unit 30 shares each of the memory areas 91A, 92A will be described later.

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

[0110] Broadcast signals such as digital broadcast signals are input to the antennas 2 a and 2 b. The antennas 2 a and 2 b are antennas for diversity reception. The digital broadcast signals input to the antennas 2 a and 2 b are output to the RF unit 10.

[0111] The RF unit 10 is made up 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 made up 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 digitally converted IF signal 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 a 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 combiner 51. Specifically, as shown in Fig. 9, the first demodulation unit 31 demodulates the signal output from the first ADC unit 21 and outputs the demodulated signal to the combiner 51. The second demodulation unit 32 demodulates the signal output from the second ADC unit 22 and outputs the demodulated signal to the combiner 51.

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

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

[0117] The error correction unit 71 generates a TS signal by performing a correction process conforming to the digital broadcasting system on the signal output from the DIL unit 61. The TS signal generated by the error correction unit 71 is output to the video / audio output unit 3.

[0118] [Operation of Digital Broadcast Receiving Device] The operation of the digital broadcast receiving device 1A will be described with reference to Figures 10A and 10B. In this example, the manner in which the demodulation unit 30 shares the storage areas 91A and 92A will be described.

[0119] FIG. 10A is a diagram showing the operation of the digital broadcast receiving device 1A according to the second embodiment.

[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 demodulator 31 processes signals in the full reception band Bf of the physical channel to output a demodulated signal s11. The first demodulator 31 performs demodulation processing using a first storage area 91A corresponding to the first demodulator 31. The second demodulator 32 processes signals in the partial reception band Bp of the physical channel to output a demodulated signal s12. The second demodulator 32 performs demodulation processing using a second storage area 92A corresponding to the second demodulator 32.

[0122] The memory capacity allocated to the first storage area 91A is the memory capacity required for digital signal processing of 35 segments. The memory capacity allocated to the second storage area 92A is the memory capacity required for digital signal processing of 9 segments. Here, if the memory capacity required for digital signal processing of 35 segments is M, the memory capacity used in the receiving device 1A of the second embodiment is (M + M / 4). Therefore, compared to the memory capacity of 2M in the prior art, it is possible to suppress an increase in the memory capacity installed in the receiving device 1A.

[0123] When processing a signal in the partial reception band Bp, the synthesis unit 51 performs the 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 combiner 51 performs the processing based only on the demodulated signal s11 output from the first demodulator 31. Note that the demodulated signal s12 output from the second demodulator 32 does not include a signal related to the non-partial reception band Bn, and therefore a signal of 0 from the second demodulator 32 is combined with the signal related to the non-partial reception band Bn output from the first demodulator 31. Therefore, the combiner 51 does not actually perform combining processing for the non-partial reception band Bn. The combiner 51 outputs the combined signal sc1 generated by this combining processing to the DIL unit 61.

[0125] For example, when a signal in the partial reception band Bp is received using one antenna 2a, the quality of the received broadcast signal is more likely to be degraded than when the signal in the partial reception band Bp is received using two antennas 2a and 2b. In contrast, in the second embodiment, when processing the partial reception band Bp, the broadcast signals received by the two antennas 2a and 2b are combined, so that a combined signal sc1 with reduced noise can be generated. According to the second embodiment, the quality of the signal in the partial reception band Bp can be improved.

[0126] Next, other examples of the operation modes of the digital broadcast receiving device 1A will be described.

[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 the second embodiment is not limited to receiving digital broadcasts of the next-generation system, but is also able to receive digital broadcasts of the current system (ISDB-T).

[0128] Fig. 10B is a diagram showing an operation mode when receiving digital broadcasts of the current standard with the digital broadcast receiving device 1A, Fig. 10B shows an example of receiving a broadcast signal of the current standard by diversity reception.

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

[0130] The synthesis unit 51 performs synthesis processing 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 synthesis unit 51 outputs the synthesis signal generated by this synthesis processing to the DIL unit 61.

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

[0132] [Digital Broadcast Receiving Method] FIG. 11 is a flowchart of a digital broadcast receiving method according to the second embodiment.

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

[0134] When the control unit 80 determines that the digital broadcasting is to be received in the current format, it outputs control signals to the RF unit 10, the demodulation unit 30, the DIL unit 61, and the error correction unit 71 so that the digital broadcasting is to be received in the current format. The receiving device 1A performs signal processing for the digital broadcasting in the current format (step S11).

[0135] On the other hand, if the control unit 80 determines that digital broadcasting will be received using the next-generation method, 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 of the partial reception band Bp (step S21A).

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

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

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

[0139] [First Modification of Second Embodiment] A first modification of the second embodiment will be described with reference to Fig. 12 and Fig. 13. In this first modification, an example will be described in which a receiving device 1A includes a pre-synthesizing unit 46A and a selecting unit 47A.

[0140] FIG. 12 is a diagram showing the configuration of a digital broadcast receiving device 1A according to a first modification of the second embodiment.

[0141] The receiving device 1A of the first modification 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, the ADC unit 20, the demodulation unit 30, the combining unit 50, the DIL unit 61, the error correction unit 71, and the control unit 80 are the same as those in the second embodiment.

[0142] In the receiving device 1A of the first modification, the first demodulation unit 31 has a pre-combining unit 46A different from the combining unit 50, and a selecting unit 47A.

[0143] The pre-synthesizer 46A generates a synthesized signal sp by synthesizing a signal being processed by the first demodulator 31 and a signal being processed by a second demodulator 32 different from the first demodulator 31. The synthesized signal sp generated by the pre-synthesizer 46A is output to the selector 47A.

[0144] Note that 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 signals input to the time axis processing unit 41 and the FFT processing unit 42, respectively.

[0145] The selector 47A receives both the signal being processed by the first demodulator 31 and the combined signal sp output from the pre-synthesizer 46A. The selector 47A selects either the signal being processed by the first demodulator 31 or the combined signal sp output from the pre-synthesizer 46A. The user can set which signal the selector 47A selects. For example, when supporting a next-generation system, the combiner 51 cannot combine signals after demodulating the entire band, so the selector 47A selects the sp output from the pre-synthesizer 46A to combine signals in advance. When supporting a current system, the combiner 51 can perform sufficient combining, so the selector 47A selects a through signal instead of the sp output from the pre-synthesizer 46A. Whether an output corresponding to the partial reception band Bp or the non-partial reception band Bn is required is determined by a request from an external device or an input operation via the input unit 4.

[0146] FIG. 13 is a diagram showing the operation of the digital broadcast receiving device 1A according to the first modification of the second embodiment.

[0147] The selector 47A of the receiving device 1A selects the signal being processed by the first demodulator 31 as the processing corresponding to the signal in the partial reception band Bp. Then, the first demodulator 31 continues processing the signal being processed by the first demodulator 31. The method of sharing the storage areas 91A and 92A by the demodulator 30 is the same as in the second embodiment.

[0148] The selector 47A selects the combined signal sp output from the pre-combiner 46A as the processing for the signal in the non-partial reception band Bn. The first demodulator 31 then processes this combined signal sp. The method of sharing the storage areas 91A, 91A by the demodulator 30 is the same as in the second embodiment.

[0149] In this first modification, broadcast signals received by the two antennas 2a and 2b are combined, allowing the pre-combiner 46A to generate a combined signal sp with reduced noise. The selector 47A selects the combined signal sp output from the pre-combiner 46A as the processing selection corresponding to the signal in the non-partial reception band Bn, and the first demodulator 31 processes the selected combined signal sp. This improves the quality of signals processed at stages subsequent to the pre-combiner 46A.

[0150] Furthermore, in this first modification, the selector 47A selects the signal being processed by the first demodulator 31 as the selection of processing corresponding to the signal of the partial reception band Bp, and the first demodulator 31 continues processing the signal being processed by the first demodulator 31. Therefore, when the signals of the partial reception band Bp are combined by the combiner 51, the combining process can be performed with the signal levels matched, and the quality of the signal output from the combiner 51 can be improved.

[0151] [Second Modification of Second Embodiment] A second modification of the second embodiment will be described with reference to Figures 14A to 14C. In this second modification, an example will be described in which the FFT size of the physical channel of the next-generation digital broadcasting system is 32k, 16k, or 8k.

[0152] FIG. 14A is a diagram showing the operation when the FFT size of the physical channel processed by the digital broadcast receiving device 1A is 32k.

[0153] The first demodulator 31 processes signals in the full reception band Bf of the physical channel to output a demodulated signal. The first demodulator 31 performs demodulation processing using a first storage area 91A corresponding to the first demodulator 31. The second demodulator 32 processes signals in the partial reception band Bp of the physical channel to output a demodulated signal. The second demodulator 32 performs demodulation processing using a second storage area 92A corresponding to the second demodulator 32.

[0154] The memory capacity allocated to the first storage area 91A is the memory capacity required for digital signal processing of 35 segments. The memory capacity allocated to the second storage area 92A is the memory capacity required for digital signal processing of 9 segments. Here, if the memory capacity required for digital signal processing of 35 segments is M, the memory capacity used in the receiving device 1A of embodiment 2 is (M + M / 4). Therefore, even when the FFT size of the physical channel is 32k, it is possible to prevent the memory capacity to be installed in the receiving device 1A from increasing.

[0155] 14B is a diagram showing the operation when the FFT size of the physical channel processed by the digital broadcast receiving device 1A is 16 kbit / s, showing an example of diversity reception using two antennas 2a and 2b.

[0156] The first demodulator 31 processes signals in the full reception band Bf of the physical channel to output a demodulated signal, and the second demodulator 32 processes signals in the partial reception band Bp of the physical channel to output a demodulated signal.

[0157] In this case, the second demodulator 32 requires a memory capacity necessary for processing signals with an FFT size of 16k during demodulation. Meanwhile, the first memory area 91A accessed by the first demodulator 31 is originally allocated a memory capacity M necessary for digital signal processing of 35 segments, which is sufficient for processing signals with an FFT size of 16k. Therefore, the control unit 80 outputs a control signal to the demodulator 30 to instruct it to change the access destination to the memory areas 91A and 92A. Based on the control signal output from the control unit 80, the second demodulator 32 accesses the second memory area 92A as well as an area M / 4 of the first memory area 91A to perform demodulation processing. Meanwhile, the first demodulator 31 performs demodulation processing using half (M / 2) of the first memory area 91A corresponding to the first demodulator 31.

[0158] According to this example, the memory capacity used by the first demodulator 31 is M / 2, the memory capacity used by the second demodulator 32 is M / 2, and the total memory capacity used is M. Therefore, even when the FFT size of the physical channel is 16k, it is possible to prevent the memory capacity to be installed in the receiving device 1A from increasing.

[0159] 14C is a diagram showing the operation when the FFT size of the physical channel processed by the digital broadcast receiving device 1A is 8 k, showing an example of diversity reception using two antennas 2 a and 2 b.

[0160] The first demodulator 31 processes signals in the full reception band Bf of the physical channel to output a demodulated signal. The first demodulator 31 performs demodulation processing using a first storage area 91A corresponding to the first demodulator 31. The second demodulator 32 processes signals in the partial reception band Bp of the physical channel to output a demodulated signal. The second demodulator 32 performs demodulation processing using a second storage area 92A corresponding to the second demodulator 32.

[0161] According to this example, the memory capacity used by each of the first demodulation unit 31 and the second demodulation unit 32 is M / 4, and the total memory capacity used is M / 2. Therefore, even when the FFT size of the physical channel is 8k, it is possible to prevent the memory capacity to be installed in the receiving device 1A from increasing.

[0162] Note that Modification 1 and Modification 2 of Embodiment 2 may be combined. In this case, the selector may select the synthesized signal sp, which is the output of the pre-synthesizer 46A, when the FFT size is 32k, and may select the through signal when the FFT size is 16k or 8k. When the FFT size is 16k or 8k, the synthesizer 51 can synthesize signals of the entire band, so by using the through signal instead of the synthesized signal sp from the pre-synthesizer 46A, optimal synthesis for each subcarrier is possible in the synthesizer 51.

[0163] (Embodiment 3) [Configuration and Operation of Digital Broadcast Receiving Device] The configuration of a digital broadcast receiving device 1B according to embodiment 3 will be described with reference to Fig. 15. In embodiment 3, an example will be described in which digital broadcast receiving device 1B is provided with storage areas 95B and 96B used by DIL units 61 and 62.

[0164] FIG. 15 is a diagram showing the configuration of a digital broadcast receiving device 1B according to the third embodiment.

[0165] The digital broadcast receiving device 1B is a device for receiving OFDM digital broadcasts, and is mounted on a mobile object such as a vehicle. Hereinafter, the digital broadcast receiving device 1B may be referred to as the receiving device 1B.

[0166] As shown in Fig. 15, receiving device 1B includes an RF unit 10, an ADC unit 20, a demodulation unit 30, a synthesis unit 50, a DIL unit 60, an error correction unit 70, and a control unit 80. Fig. 15 also shows a video / audio output unit 3 that outputs video and audio, and an input unit 4 that accepts operational input from a user. Fig. 15 also shows multiple antennas 2a, 2b, 2c, and 2d connected to receiving device 1B.

[0167] The configurations of the RF unit 10, the ADC unit 20, the demodulation unit 30, the combining unit 50, the DIL unit 60, and the error correction unit 70 are the same as those in the first embodiment.

[0168] The memory unit 90 included in the control unit 80 has a first memory area 91, a second memory area 92, a third memory area 93, and a fourth memory area 94. The memory unit 90 of the third embodiment further includes a fifth memory area 95B and a sixth memory area 96B. Each of the memory areas 95B and 96B stores data for digital signal processing during operation of the receiving device 1B. While the memory unit 90 is described as being included in the control unit 80, it may be located anywhere on a single chip including the demodulation unit 30 and the DIL unit 60. The memory unit 90 may be configured as a single memory macro, or may be configured as multiple memory macros located in different locations on the chip. The control unit 80 may also include a memory unit other than the memory unit 90. In this example, the manner in which the DIL units 61 and 62 share the memory areas 95B and 96B will be described.

[0169] 16A is a diagram showing a first operation mode m1 of the digital broadcast receiving device 1B, and FIG. 16B is a diagram showing a second operation 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 the control signal output from the control unit 80. Based on the band selection input received by the input unit 4, the control unit 80 switches between operating the receiving device 1B in a first operation mode m1 and operating in a second operation mode m2.

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

[0172] The first DIL unit 61 performs deinterleaving processing on the combined signal sc1 output from the first combining unit 51 in accordance with the digital broadcasting standard. The signal processed by the first DIL unit 61 is output to a first error correction unit 71. The first error correction unit 71 performs correction processing on the signal output from the first DIL unit 61 in accordance with the digital broadcasting standard, thereby generating a TS signal. The TS signal generated by the first error correction unit 71 is output to the video / audio output unit 3.

[0173] The second DIL unit 62 performs deinterleaving processing on the combined signal sc2 output from the second combiner 52 in accordance with the digital broadcasting standard. The signal processed by the second DIL unit 62 is output to a 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 standard. 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 specifying the storage areas 95B, 96B to be used when the DIL unit 60 performs the deinterleaving process to the DIL unit 60. The first DIL unit 61 and the second DIL unit 62 each perform the deinterleaving process using the storage areas 95B, 96B based on this control signal.

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

[0176] Here, when the FFT size is 32 k, the memory amount required by the DIL unit for signal processing of the entire reception band Bf for one system is assumed to be N. Furthermore, if the memory amount allocated to one storage area in the first operating mode m1 is assumed to be N / 2, the memory amount required for two storage areas in this embodiment is 2 × N / 2 = N. Since the memory amount required to process signals in the partial reception band Bp is approximately N / 4, the memory amount processed by each of the first DIL unit 61 and the second DIL unit 62 is approximately N / 4. Therefore, the memory amount N / 2 allocated to the DIL unit 60 fully covers the memory amount required for data processing in the first operating mode m1.

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

[0178] In the second operating mode m2, the first DIL unit 61 requires a memory capacity N necessary for digital signal processing of the entire reception band Bf. Therefore, the control unit 80 outputs a control signal to the DIL unit 60 instructing it to change the access destination to the storage 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 storage area 95B but also another storage area different from the fifth storage area 95B to perform deinterleaving. Specifically, the first DIL unit 61 performs deinterleaving using both the fifth storage area 95B and the sixth storage area 96B. In this example, the memory capacity used by the first DIL unit 61 is 2×N / 2=N.

[0179] In this way, by changing the way in which the DIL unit 60 shares the storage areas 95B and 96B depending on the operation mode of the receiving device 1B, it is possible to prevent 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, another example of the operation mode of the digital broadcast receiving device 1B will be described.

[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 the third embodiment is not limited to receiving digital broadcasts of the next-generation system, but is also able to receive digital broadcasts of the current system (ISDB-T).

[0182] Fig. 16C is a diagram showing an operation mode when receiving digital broadcasts of the current standard by the digital broadcast receiving device 1B, Fig. 16C shows an example of receiving a broadcast signal of the current standard by diversity reception.

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

[0184] The first DIL unit 61 performs processing using a fifth storage area 95B corresponding to the first DIL unit 61. The second DIL unit 62 performs processing using a sixth storage area 96B corresponding to the second DIL unit 62.

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

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

[0187] FIG. 17A is a diagram showing the second operation mode m2 when the FFT size of the physical channel processed by the digital broadcast receiving device 1B is 32k.

[0188] 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 storage area 95B but also another storage area different from the fifth storage area 95B to perform deinterleaving. Specifically, the first DIL unit 61 performs deinterleaving using both the fifth storage area 95B and the sixth storage area 96B.

[0189] According to this example, the memory capacity used by the first DIL unit 61 is 2×N / 2=N. Therefore, when the FFT size of the physical channel is 32k, it is possible to prevent the memory capacity to be installed in the receiving device 1B from increasing.

[0190] 17B is a diagram showing a second operation mode m2 when the FFT size of the physical channel processed by the digital broadcast receiving device 1B is 16 kbit / s, in which diversity reception is performed using two antennas 2 a and 2 c.

[0191] 17B, ​​the first DIL unit 61 of the DIL unit 60 processes signals in the entire reception band Bf. The first DIL unit 61 and the second DIL unit 62 access the fifth storage area 95B and the sixth storage area 96B, respectively, to perform deinterleaving.

[0192] According to this example, the memory capacity used by the first DIL unit 61 is N / 2, the memory capacity used by the second DIL unit 62 is N / 2, and the total memory capacity used is N. Therefore, when the FFT size of the physical channel is 16 k, it is possible to prevent the memory capacity to be installed in the receiving device 1B from increasing.

[0193] 17C is a diagram showing a second operating mode m2 when the FFT size of the physical channel processed by the digital broadcast receiving device 1B is 8k, in which an example of diversity reception using four antennas 2a to 2d is shown.

[0194] 17C, the DIL unit 60 processes signals in the entire reception band Bf. The first DIL unit 61 and the second DIL unit 62 access the fifth storage area 95B and the sixth storage area 96B, respectively, to perform deinterleaving.

[0195] According to this example, the memory capacity used by each of the first DIL unit 61 and the second DIL unit 62 is N / 4, and the total memory capacity used is N / 2. Therefore, when the FFT size of the physical channel is 8k, it is possible to prevent the memory capacity to be installed in the receiving device 1B from increasing.

[0196] Note that Modification 1 of the third embodiment can be applied even to systems that do not have a partial reception band. For example, it may be applied to DVB-T2 (Digital Video Broadcasting-Terrestrial 2) and ATSC3.0 (Advanced Television Systems Committee 3.0), in which the FFT size is up to 32k, or systems similar to these systems, and any system in which the FFT size exceeds 8k may be applied. Furthermore, in a system in which the FFT size differs for each subframe, such as ATSC3.0, for example, if the FFT size of subframe #1 is 8k and the FFT size of subframe #2 is 32k, the system may operate in the operating mode of Figure 17C when receiving subframe #1 and in the operating mode of 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. A physical channel of the digital broadcast has a partial reception band Bp, which is a portion of the reception band. The digital broadcast receiving device 1 includes a plurality of demodulators 30 that perform demodulation processing and a combiner 50 that combines outputs from the plurality of demodulators 30. In a first operating mode m1, the plurality of demodulators 30 process signals in the partial reception band Bp of the same physical channel to output a plurality of demodulated signals s1. The combiner 50 processes the partial reception band Bp based on the plurality of demodulated signals s1 output from the plurality of demodulators 30. In a second operating mode m2 different from the first operating mode m1, one demodulator (e.g., demodulator 31) of the plurality of demodulators 30 processes signals in the entire reception band Bf, including the partial reception band Bp, to output a single demodulated signal s2. The combiner 50 performs processing for the entire reception band Bf based on one demodulated signal s2 output from one demodulator 31.

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

[0199] The plurality of 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. The one demodulation unit may be the first demodulation unit 31.

[0200] This makes it possible to change the demodulated signals output from the plurality of demodulators 30 and the demodulated signal output from the first demodulator 31 according to the operation mode of the receiver 1, and further change the synthesis process of the synthesizer 50 based on the demodulated signals, thereby providing a receiver 1 that can support reception of next-generation digital broadcasting.

[0201] In the first operation mode m1, the first demodulation unit 31 performs processing using a first storage area 91 corresponding to the first demodulation unit 31, the second demodulation unit 32 performs processing using a second storage area 92 corresponding to the second demodulation unit 32, the third demodulation unit 33 performs processing using a third storage area 93 corresponding to the third demodulation unit 33, and the fourth demodulation unit 34 performs processing using a fourth storage area 94 corresponding to the fourth demodulation unit 34. In the second operation mode m2, the first demodulation unit 31 may perform processing using the first storage area 91 and at least a part of the second storage area 92, the third storage area 93, and the fourth storage area 94.

[0202] According to this configuration, the way in which the demodulation unit 30 shares the storage areas 91 to 94 can be changed depending on the operation 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 signals in the partial reception band Bp processed in the first operation mode m1 are signals based on digital broadcasts input from a plurality of antennas 2a to 2d that correspond one-to-one to a plurality of demodulation units 30. The signals in the full reception band Bf processed in the second operation mode m2 may be signals based on digital broadcasts input from one antenna 2a that corresponds to one demodulation unit 31.

[0204] This allows the demodulation unit 30 to change how it shares the storage areas 91 to 94 depending on whether digital broadcasts are received via multiple antennas 2a to 2d or via a single antenna 2a, thereby providing a receiver 1 that can support the reception of next-generation digital broadcasts.

[0205] Each of the plurality of demodulators 30 includes a time axis processor 41 that performs time axis processing of the digital broadcasting waves, an FFT processor 42 connected to the output side of the time axis processor 41, a subcarrier synchronizer 43 connected to the output side of the FFT processor 42, and a transmission channel estimator 44 connected to the output side of the subcarrier synchronizer 43. In a first operation mode m1, the plurality of demodulators 30 output a plurality of demodulated signals s1 using their respective time axis processors 41, FFT processors 42, subcarrier synchronizers 43, and transmission channel estimators 44. In a second operation mode m2, one demodulator 31 may output a single demodulated signal s2 using its own time axis processor 41, FFT processor 42, subcarrier synchronizer 43, and transmission channel estimator 44.

[0206] According to this configuration, the demodulated signal output from the demodulation unit 30 can be changed depending on the operation 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 demodulator 31 has a pre-synthesizer 46 that is different from the synthesizer 50. The pre-synthesizer 46 generates a synthesized signal sp by synthesizing a signal being processed by one demodulator 31 with a signal being processed by another demodulator different from the one demodulator 31. In the second operating mode m2, one demodulator 31 may process the synthesized signal sp generated by the pre-synthesizer 46.

[0208] This configuration allows the pre-synthesizer 46 to generate a synthesized signal sp with reduced noise, thereby improving the quality of signals processed downstream of the pre-synthesizer 46. This makes it possible to provide a receiving device 1 capable of receiving next-generation digital broadcasts.

[0209] Furthermore, the signal being processed in one demodulation unit 31 and the signal being processed in another demodulation unit may each 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-synthesizer 46 to appropriately generate a noise-suppressed synthesized signal sp, thereby improving the quality of signals processed downstream of the pre-synthesizer 46. This makes it possible to provide a receiver 1 capable of receiving next-generation digital broadcasts.

[0211] Furthermore, each demodulator 31 further includes a selector 47 to which both the signal being processed by the demodulator 31 and the combined signal sp generated by the pre-combiner 46 are input. In a first operating mode m1, the selector 47 selects the signal being processed by the demodulator 31, and the demodulator 31 continues to process the signal being processed by the demodulator 31. In a second operating mode m2, the selector 47 may select the combined signal sp, and the demodulator 31 may process the combined signal sp.

[0212] With this configuration, in the first operating mode m1, a signal being processed by one demodulator 31 can be selected, and in the second operating mode m2, a synthesized signal sp output from the pre-synthesizer 46 can be selected. This makes it possible to improve the quality of signals processed in stages subsequent to the pre-synthesizer 46, as necessary. This makes it possible to provide a receiving device 1 that can receive next-generation digital broadcasts.

[0213] In addition, the digital broadcasting waves include parameters related to the FFT size, and when the FFT size is compatible with 32k in the second operating mode m2, the synthesis unit 50 may perform processing on the entire receiving band Bf based on only one demodulated signal output from one demodulation unit 31.

[0214] In addition, when the digital broadcasting waves include parameters related to the FFT size, and the FFT size is compatible with 16k in the second operating mode m2, the synthesis unit 50 may perform processing on the entire receiving 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] In addition, when the digital broadcasting waves include parameters related to the FFT size, and the FFT size is compatible with 8k in the second operating mode m2, the synthesis unit 50 may perform processing on the entire receiving band Bf based on one demodulated signal output from the first demodulation unit 31 and the demodulated signals output from each of the second demodulation unit 32, the third demodulation unit 33, and the fourth demodulation unit 34.

[0216] Alternatively, the physical channel may be configured with 35 consecutive frequency band segments, and the partial reception band may be the central 9 segments of the 35 segments.

[0217] This makes it possible to provide a receiving device 1 that can receive digital broadcasts having a physical channel made up 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 channel of the digital broadcast has a partial reception band Bp, which is a 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 demodulator 31 and a second demodulator 32 that perform demodulation processing, and a combiner 51 that combines the outputs of the first demodulator 31 and the second demodulator 32. The combiner 51 processes signals in the partial reception band Bp based on the demodulated signals output from the first demodulator 31 and 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.

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

[0220] The first demodulation unit 31 also has a pre-synthesis unit 46A that is different from the synthesis unit 51. The pre-synthesis unit 46A generates a synthesized signal sp by synthesizing the signal being processed by the first demodulation unit 31 and the signal being processed by the second demodulation unit 32. The first demodulation unit 31 may process the synthesized signal sp generated by the pre-synthesis unit 46A.

[0221] This configuration allows the pre-synthesizer 46A to generate a synthesized signal sp with reduced noise, thereby improving the quality of signals processed downstream of the pre-synthesizer 46A. This makes it possible to provide a receiver 1A capable of receiving next-generation digital broadcasts.

[0222] 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 the digital broadcasting waves, 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 channel 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-synthesizer 46A to appropriately generate a noise-suppressed synthesized signal sp, thereby improving the quality of signals processed downstream of the pre-synthesizer 46A. This makes it possible to provide a receiver 1A capable of receiving next-generation digital broadcasts.

[0224] Furthermore, digital broadcast waves include parameters related to FFT size. The combiner 51 has a first processing mode performed when the FFT size is compatible with 32k and a second processing mode performed when the FFT size is compatible with 16k or 8k. In the first processing mode, the combiner 51 performs processing corresponding to signals of the partial reception band Bp based on the demodulated signals output from the first demodulator 31 and the second demodulator 32, and performs processing corresponding to signals of the non-partial reception band Bn based only on the demodulated signal output from the first demodulator 31. In the second processing mode, the combiner 51 may perform processing on both signals of the partial reception band Bp and signals of 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 FIG. 14A, and the second processing mode is the processing mode shown in FIG. 14B or FIG. 14C.

[0226] Furthermore, the physical channel may be composed of 35 consecutive frequency band segments, the partial reception band Bp being the 9 segments located in the middle of the 35 segments, and the non-partial reception band Bn being the 26 segments excluding the partial reception band Bp.

[0227] This makes it possible to provide a receiving device 1A that can accommodate reception of digital broadcasts having a physical channel made up of 35 segments.

[0228] The digital broadcast receiving method of this embodiment is a method for receiving OFDM digital broadcasts. A physical channel of the digital broadcast has a partial reception band Bp, which is a portion of the reception band. The digital broadcast receiving method selectively performs processing in a first operation mode m1 or processing in a second operation mode m2, which is different from the first operation mode m1. In the processing in the first operation mode m1, multiple demodulators 30 process signals in the partial reception band Bp of the same physical channel to output multiple demodulated signals s1, and a combiner 50 processes the partial reception band Bp based on the multiple demodulated signals s1. In the processing in the second operation mode m2, one demodulator (e.g., demodulator 31) of the multiple demodulators 30 processes signals in the entire reception band Bf, including the partial reception band Bp, to output a single demodulated signal s2, and the combiner 50 processes the entire reception band Bf based on the single 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 broadcasting, it is possible to provide a receiving method that can accommodate the reception of next-generation digital broadcasting.

[0230] The digital broadcast receiving method of this embodiment is a method for receiving OFDM digital broadcasts. The physical channel of the digital broadcast has a partial reception band Bp, which is a part of the reception band, and a non-partial reception band Bn, which is different from the partial reception band Bp. In the digital broadcast receiving method, processing corresponding to the signal in the partial reception band Bp involves performing synthesis processing based on the demodulated signal output from the first demodulator 31 and the demodulated signal output from the second demodulator 32, and processing corresponding to the signal in the non-partial reception band Bn involves performing processing based only on the demodulated signal output from the first demodulator 31.

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

[0232] (Other Embodiments) While the digital broadcast receiving device according to aspects of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. For example, the present disclosure may be embodied in another embodiment realized by arbitrarily combining the components described in this specification or excluding some of the components. Furthermore, the present disclosure also includes modifications obtained by applying various modifications to the above-described embodiments that would occur to a person skilled in the art without departing from the spirit of the present disclosure, i.e., the meaning of the wording set forth in the claims.

[0233] The following aspects may also be included within the scope of one or more aspects of the present disclosure.

[0234] (1) Some of the components constituting the 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 operates in accordance with the computer program to achieve its functions. Here, the computer program is composed of a combination of multiple instruction codes that indicate commands to a computer to achieve a predetermined function.

[0235] (2) Some of the components constituting the digital broadcast receiving device may be configured as a single system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating multiple components on a single chip, and specifically, is a computer system configured including a microprocessor, ROM, RAM, etc. A computer program is stored in the RAM. The system LSI achieves its functions by the microprocessor operating in accordance with the computer program.

[0236] (3) Some of the components constituting the digital broadcast receiving device may be configured as an IC card or a standalone module that can be attached to each device. The IC card or module may be a computer system composed of a microprocessor, ROM, RAM, etc. The IC card or module may include the ultra-multifunctional LSI. The IC card or module achieves its functions by the microprocessor operating in accordance with a computer program. The IC card or module may be tamper-resistant.

[0237] (4) Furthermore, some of the components constituting the digital broadcast receiving device may be the computer program or the digital signal recorded on a computer-readable recording medium, such as a flexible disk, hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray (registered trademark) Disc), semiconductor memory, etc. Alternatively, the components may be the digital signal recorded on such a recording medium.

[0238] In addition, some of the components constituting the above-mentioned digital broadcast receiving device may transmit the computer program or the digital signal via a telecommunications line, a wireless or wired communication line, a network such as the Internet, data broadcasting, etc.

[0239] (5) The present disclosure may be embodied as the methods described above, a computer program that implements these methods on a computer, or a digital signal that includes the computer program.

[0240] (6) The present disclosure may also be a computer system having a microprocessor and a memory, the memory storing the computer program, and the microprocessor operating in accordance with the computer program.

[0241] (7) The program or the digital signal may also be implemented 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, etc.

[0242] (8) The above-described embodiments and modifications may be combined with each other.

[0243] The digital broadcast receiving device of the present disclosure can be used as a broadcast receiving device mounted on a mobile object such as a vehicle.

[0244] DESCRIPTION OF SYMBOLS 1, 1A, 1B Digital broadcast receiving device (receiving device) 2a, 2b, 2c, 2d Antenna 3 Video and audio output unit 4 Input unit 10, 11, 12, 13, 14 RF unit 20, 21, 22, 23, 24 ADC unit (A-D conversion unit) 30, 31, 32, 33, 34 Demodulation unit 41 Time axis processing unit 42 FFT processing unit 43 Subcarrier synchronization unit 44 Transmission path estimation unit 45 Equalization unit 46, 46A Pre-combining unit 47, 47A Selection unit 50, 51, 52 Combining unit 60, 61, 62 DIL unit (deinterleaving unit) 70, 71, 72 Error correction unit 80 Control unit 90 Memory unit 91, 91A, 92, 92A, 93, 94, 95B, 96B Storage area Bf: Full reception band Bp: Partial reception band Bn: Non-partial reception band m1: First operation mode m2: Second operation mode s1, s2, s11, s12: Demodulated signals sc1, sc2, sp: Combined signals

Claims

1. A digital broadcast receiving device for receiving digital broadcasts in an OFDM (Orthogonal Frequency Division Multiplexing) system, The physical channel of the digital broadcasting has a partial reception band that is a part of a reception band, The digital broadcast receiving device includes: A plurality of demodulation units that perform demodulation processing, and a synthesis unit that synthesizes outputs of the plurality of demodulation units, In a first mode of operation, The plurality of demodulation units output a plurality of demodulated signals by processing signals of the partial reception band of the same physical channel; The combiner performs processing for the partial reception band based on the plurality of demodulated signals output from the plurality of demodulators, In a second operating mode different from the first operating mode, One of the demodulation units processes signals in an entire reception band including the partial reception band to output one demodulated signal; The synthesizer performs processing for the entire reception band based on the one demodulated signal output from the one demodulator. Digital broadcast 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 one demodulation unit is the first demodulation unit.

2. The digital broadcast receiving device according to claim 1.

3. In the first mode of operation: the first demodulation unit performs processing using a first storage area corresponding to the first demodulation unit; the second demodulation unit performs processing using a second storage area corresponding to the second demodulation unit; the third demodulation unit performs processing using a third storage area corresponding to the third demodulation unit; the fourth demodulation unit performs processing using a fourth storage area corresponding to the fourth demodulation unit; In the second mode of operation, The first demodulation unit performs processing using the first storage area and at least a part of the second storage area, the third storage area, and the fourth storage area.

3. The digital broadcast receiving device according to claim 2.

4. the partial reception band signals processed in the first operation mode are signals based on the digital broadcasting input from a plurality of antennas corresponding one-to-one to the plurality of demodulation units, The signal of the entire reception band processed in the second operation mode is a signal based on the digital broadcast input from one antenna corresponding to one demodulation unit.

4. The digital broadcast receiving device according to claim 1.

5. Each of the plurality of demodulation units a time axis processing unit that performs time axis processing of the broadcast wave of the digital broadcast; an FFT processing unit connected to an output side of the time axis processing unit; A subcarrier synchronization unit connected to an output side of the FFT processing unit; a transmission path estimator connected to an output side of the subcarrier synchronization unit; having In the first mode of operation: the plurality of demodulation units output the plurality of demodulated signals using the respective time axis processing units, the FFT processing units, the subcarrier synchronization units, and the transmission channel estimation units; In the second mode of operation, The one demodulation unit outputs the one demodulated signal using the time axis processing unit, the FFT processing unit, the subcarrier synchronization unit, and the transmission path estimation unit of the one demodulation unit.

4. The digital broadcast receiving device according to claim 1.

6. The one demodulation unit has a pre-synthesis unit different from the synthesis unit, The pre-synthesizing unit synthesizes a signal being processed by the one demodulation unit and a signal being processed by another demodulation unit different from the one demodulation unit to generate a synthesized signal; In the second mode of operation, The one demodulation unit processes the synthesized signal generated by the pre-synthesizing unit.

6. The digital broadcast receiving device according to claim 5.

7. The signal being processed in the one demodulation unit and the signal being processed in the other demodulation unit are the same signal as the signal input to the time axis processing unit or the signal input to the FFT processing unit.

7. The digital broadcast receiving device according to claim 6.

8. The one demodulation unit further has a selection unit to which both the signal being processed by the one demodulation unit and the synthesized signal generated by the pre-synthesizing unit are input, In the first mode of operation: The selection unit selects a signal being processed by the one demodulation unit, The one demodulation unit continues to process the signal being processed by the one demodulation unit, In the second mode of operation, The selection unit selects the composite signal, The one demodulation unit processes the composite signal.

7. The digital broadcast receiving device according to claim 6.

9. The digital broadcasting transmission method includes a parameter related to an FFT size, When the FFT size corresponds to 32k in the second operation mode, The synthesizer performs processing for the entire reception band based on only the one demodulated signal output from the one demodulator.

4. The digital broadcast receiving apparatus according to claim 2 or 3.

10. The digital broadcasting transmission method includes a parameter related to an FFT size, When the FFT size corresponds to 16k in the second operation mode, The combiner performs processing for the entire reception band based on the one demodulated signal output from the first demodulator and one of the demodulated signals output from the second demodulator, the third demodulator, and the fourth demodulator.

4. The digital broadcast receiving apparatus according to claim 2 or 3.

11. The digital broadcasting transmission method includes a parameter related to an FFT size, When the FFT size corresponds to 8k in the second operation mode, The combiner performs processing for the entire reception band based on the one demodulated signal output from the first demodulator and the demodulated signals output from the second demodulator, the third demodulator, and the fourth demodulator.

4. The digital broadcast receiving apparatus according to claim 2 or 3.

12. The physical channel is composed of 35 consecutive segments of a frequency band, The partial reception band is the central 9 segments of the 35 segments.

4. The digital broadcast receiving device according to claim 1.

13. A digital broadcast receiving device for receiving digital broadcasts in an OFDM (Orthogonal Frequency Division Multiplexing) system, a physical channel of the digital broadcasting has a partial reception band that is a part of a reception band and a non-partial reception band different from the partial reception band; The digital broadcast receiving device includes: a first demodulation unit and a second demodulation unit for performing demodulation processing; a combiner that combines an output of the first demodulator and an output of the second demodulator; Equipped with The synthesis unit is performing a process corresponding to the partial reception band signal based on the demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit; As a process corresponding to the signal of the non-partial reception band, a process is performed based only on the demodulated signal output from the first demodulation unit. Digital broadcast receiving device.

14. The first demodulation unit has a pre-synthesis unit different from the synthesis unit, The pre-synthesizing unit synthesizes a signal being processed by the first demodulation unit and a signal being processed by the second demodulation unit to generate a synthesized signal; The first demodulation unit processes the composite signal generated by the pre-combination unit. The digital broadcast receiving device according to claim 13.

15. Each of the first demodulation unit and the second demodulation unit a time axis processing unit that performs time axis processing of the broadcast wave of the digital broadcast; an FFT processing unit connected to an output side of the time axis processing unit; A subcarrier synchronization unit connected to an output side of the FFT processing unit; a transmission path estimator connected to an output side of the subcarrier synchronization unit; having The signal being processed by the first demodulation unit and the signal being processed by the second demodulation unit are the same signal as the signal input to the time axis processing unit or the signal input to the FFT processing unit. The digital broadcast receiving device according to claim 14.

16. The digital broadcasting transmission method includes a parameter related to an FFT size, The synthesis unit is a first processing mode that is performed when the FFT size is 32k compatible, and a second processing mode that is performed when the FFT size is 16k compatible or 8k compatible; In the first processing mode, a process corresponding to a signal in the partial reception band is performed based on a demodulated signal output from the first demodulation unit and a demodulated signal output from the second demodulation unit, and a process corresponding to a signal in the non-partial reception band is performed based only on a demodulated signal output from the first demodulation unit; In the second processing mode, processing is performed on both the partial reception band signal and the non-partial reception band signal based on both the first demodulation unit and the second demodulation unit. The digital broadcast receiving device according to any one of claims 13 to 15.

17. The physical channel is composed of 35 consecutive segments of a frequency band, The partial reception band is 9 segments located in the center of the 35 segments, The non-partial reception band is 26 segments excluding the partial reception band. The digital broadcast receiving device according to any one of claims 13 to 15.

18. A digital broadcast receiving method for receiving digital broadcasts in an OFDM (Orthogonal Frequency Division Multiplexing) format, comprising: The physical channel of the digital broadcasting has a partial reception band that is a part of a reception band, The digital broadcast receiving method includes selectively executing a process in a first operation mode and a process in a second operation mode different from the first operation mode; In the process in the first operation mode, A plurality of demodulation units process signals of the partial reception band of the same physical channel to output a plurality of demodulated signals, and a synthesis unit processes the partial reception band based on the plurality of demodulated signals; In the process in the second operation mode, One of the demodulation units processes signals of an entire reception band including the partial reception band to output one demodulated signal, and the synthesis unit performs processing for the entire reception band based on the one demodulated signal. How to receive digital broadcasts.

19. A digital broadcast receiving method for receiving digital broadcasts in an OFDM (Orthogonal Frequency Division Multiplexing) format, comprising: a physical channel of the digital broadcasting has a partial reception band that is a part of a reception band and a non-partial reception band different from the partial reception band; In the digital broadcast receiving method, performing a synthesis process based on the demodulated signal output from the first demodulation unit and the demodulated signal output from the second demodulation unit as a process corresponding to the signal in the partial reception band; As a process corresponding to the signal of the non-partial reception band, a process is performed based only on the demodulated signal output from the first demodulation unit. How to receive digital broadcasts.

20. A digital broadcast receiving device for receiving digital broadcasts in an OFDM (Orthogonal Frequency Division Multiplexing) system, comprising: The digital broadcast transmission method has a frame structure, one frame is composed of a plurality of subframes, and includes a parameter related to an FFT size for each of the plurality of subframes; The digital broadcast receiving device includes a plurality of demodulation units that perform demodulation processing, and a synthesis unit that synthesizes outputs of the plurality of demodulation units, a first demodulation unit which is one of the plurality of demodulation units processes the digital broadcast signal to output one demodulated signal; The synthesizing unit processes the digital broadcast signal based on at least the one demodulated signal output from the first demodulation unit, If the FFT size in one subframe of the plurality of subframes corresponds to 32k, The synthesis unit processes the digital broadcast signal based on only the one demodulated signal output from the one demodulation unit, When the FFT size in the one subframe corresponds to 16k or 8k, The synthesizer performs processing on the digital broadcast signal based on at least two or more demodulated signals output from the plurality of demodulators. Digital broadcast receiving device.

21. The plurality of demodulation units include a second demodulation unit, a third demodulation unit, and a fourth demodulation unit in addition to the first demodulation unit, When the FFT size in the one subframe corresponds to 8k, the synthesis 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; When the FFT size in the one subframe corresponds to 16k, The synthesizer performs processing on the digital broadcast signal based only on the one demodulated signal output from the first demodulator and the demodulated signal output from the second demodulator.

21. The digital broadcast receiving device according to claim 20.

22. The plurality of demodulation units each have a memory area that is physically different from each other, the first demodulation unit has a first storage area; the second demodulation unit has a second storage area; the third demodulation unit has a third storage area, the fourth demodulation unit has a fourth storage area, When the FFT size in the one subframe is compatible with 8k, the first demodulation unit uses the first storage area, the second demodulation unit uses the second storage area, the third demodulation unit uses the third storage area, and the fourth demodulation unit uses the fourth storage area, and performs processing on the digital broadcast signal; When the FFT size in the one subframe corresponds to 32 k, the first demodulation unit performs processing on the digital broadcast signal using the second storage area, the third storage area, and the fourth storage area in addition to the first storage area.

22. The digital broadcast receiving device according to claim 21.

23. The plurality of demodulation units each have a memory area that is physically different from each other, the first demodulation unit has a first storage area; the second demodulation unit has a second storage area; the third demodulation unit has a third storage area, the fourth demodulation unit has a fourth storage area, When the FFT size in the one subframe is compatible with 8k, the first demodulation unit uses the first storage area, the second demodulation unit uses the second storage area, the third demodulation unit uses the third storage area, and the fourth demodulation unit uses the fourth storage area, and performs processing on the digital broadcast signal; When the FFT size in the one subframe 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, and performs processing on the digital broadcast signal.

22. The digital broadcast receiving device according to claim 21.