Channel processor

Abstract

To provide a technique of providing a channel processor capable of suppressing influence of a suspended channel.SOLUTION: A first frequency conversion part 321 frequency-converts, for a processing channel which is set in a non-signal band, a signal in a target channel. The second frequency conversion part 324 frequency-converts, for one of channels included in the signal band, the signal in the processing channel. An AGC part 323 performs level adjustment such that a signal level of the target channel is a preset target level LV. A controller 7 configures the second frequency conversion part 324 such that an output frequency of the target channel that is determined to be in a suspended state is maintained in the frequency of the processing channel.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a technique for adjusting the signal level of a BS / CS-IF signal. [Background technology]

[0002] The following Patent Document 1 describes a channel processor that separates a television broadcast signal into signals for each broadcast channel and adjusts the signal level of each broadcast channel to an appropriate level. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4838163 Summary of the Invention [Problem to be solved by the invention]

[0004] The channel processor is equipped with an automatic gain control (AGC) function to adjust the signal level of each channel. When there is an out-of-service channel with no input signal, the AGC function amplifies the noise detected in the out-of-service channel at full gain to match the signal level of the other channels. As a result, there are problems such as the amplified noise adversely affecting the signals of other channels and the amplifier that realizes the AGC function being prone to oscillation.

[0005] One aspect of the present disclosure provides a technique for suppressing the effects of out-of-service channels in a channel processor. [Means for solving the problem]

[0006] One aspect of the present disclosure is a channel processor comprising a signal processing unit, a filter, and a control unit. The signal processing unit is configured to process a BS / CS-IF signal input from an input terminal for each channel included in the BS / CS-IF signal. The filter is configured to set at least one of a band other than the signal band to be processed by the signal processing unit and a guard band within the signal band as a non-signal band, and to suppress and output signals in the non-signal band from the signals output from the signal processing unit. The control unit controls the operation of the signal processing unit.

[0007] The signal processing unit includes a first frequency conversion unit, a second frequency conversion unit, and an automatic gain adjustment unit. The first frequency conversion unit is configured to frequency convert a signal of a target channel, which is a channel to be processed, to a processing channel set in a non-signal band. The second frequency conversion unit is configured to frequency convert a signal of the processing channel to one of the channels belonging to the signal band. The automatic gain adjustment unit is configured to adjust the signal level of the target channel to a set target level.

[0008] The control unit includes a determination unit and a conversion unit. The determination unit is configured to determine whether or not the target channel is out of service based on the signal level of the processing channel. The conversion setting unit is configured to set the second frequency conversion unit so that the signal of the target channel determined by the determination unit to be out of service remains in a non-signal band.

[0009] With this configuration, the signal (i.e., noise) of a channel determined to be out of service is not returned from the processing channel to the original channel, which improves the signal-to-noise ratio of the BS / CS-IF signal output via the channel processor, and also prevents the out-of-service channel from affecting other channels.

[0010] In one aspect of the present disclosure, the control unit may further include a level setting unit configured to set a target level of an automatic gain control unit that adjusts the level of a target channel determined by the determination unit to be out of broadcasting to a level that can be regarded as no signal.

[0011] With this configuration, the automatic gain control unit that processes the signal of a channel determined to be out of service does not go to full gain, so that oscillation due to noise in the channel determined to be out of service can be suppressed.

[0012] In one aspect of the present disclosure, the signal processing unit may include a branching circuit, a right-handed processing unit, a left-handed processing unit, and a multiplexing circuit. The branching circuit is configured to branch the BS / CS-IF signal into a right-handed signal and a left-handed signal. The right-handed processing unit is configured to process the right-handed signal branched by the branching circuit. The left-handed processing unit is configured to process the left-handed signal branched by the branching circuit. The multiplexing circuit is configured to multiplex and output the signals output from the right-handed processing unit and the left-handed processing unit. The right-handed processing unit and the left-handed processing unit each include a first frequency conversion unit, a second frequency conversion unit, and an automatic gain adjustment unit. In addition, the non-signal band is set individually for each of the right-handed processing unit and the left-handed processing unit.

[0013] According to this configuration, the processing of the signal processing unit is divided into a right-handed processing unit and a left-handed processing unit, so that the processing load on the right-handed processing unit and the left-handed processing unit can be reduced compared to when the BS / CS-IF signals are processed collectively.

[0014] In one aspect of the present disclosure, a downconverter and an upconverter may be included. The downconverter is configured to convert the left-handed signal into a signal whose signal band overlaps at least a part with the right-handed signal, and input the signal to the left-handed processing unit. The upconverter is configured to convert the signal output from the left-handed processing unit into a signal in the original signal band of the left-handed signal. The left-handed processing unit may be configured to process a signal in the same signal band as the right-handed processing unit.

[0015] According to this configuration, the right-handed and left-handed processing sections can be made to have the same configuration, which makes manufacturing easier. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a block diagram showing the configuration of a channel processor according to the first embodiment. [Diagram 2] FIG. 2 is a block diagram showing the configuration of a signal processing unit and a control unit. [Diagram 3] 3A to 3C are explanatory diagrams showing examples of waveform patterns representing basic characteristics of a signal output from a signal processing unit and waveform patterns realized by a waveform adjustment circuit. [Figure 4] 11 is a flowchart of a mode confirmation process executed by a control unit. [Diagram 5] 11 is a flowchart of a noise measurement process executed by a control unit. [Figure 6] 4 is a flowchart of a squelch / level adjustment process executed by a control unit. [Figure 7] FIG. 4 is an explanatory diagram showing an overview of the operation of a signal processing unit. [Figure 8] FIG. 11 is a block diagram showing a configuration of a signal processing unit in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. First embodiment] [1-1. Configuration] 1 receives a BS / CS-IF signal from a BS / CS antenna 81 or the like via an input terminal 11, adjusts the signal level of each broadcast channel contained in the BS / CS-IF signal, and outputs it from an output terminal 12. A terminal device 82 such as a television that uses the BS / CS-IF signal is connected to the output terminal 12.

[0018] BS / CS-IF signals are signals with frequencies in the range of 1032 MHz to 3224 MHz (hereinafter referred to as the signal band). BS / CS-IF signals are made up of a total of 50 channels, including 12 channels of BS right-handed and BS left-handed signals, and 13 channels of CS right-handed and CS left-handed signals.

[0019] The channel processor 1 includes a filter 2, a signal processing section 3, a filter 4, an amplifier circuit 5, a waveform adjustment circuit 6, and a control section . The filter 2 attenuates signals outside the signal band from the BS / CS-IF signal input from the input terminal 11. As the filter 2, for example, a high-pass filter is used.

[0020] The signal processor 3 performs squelch processing and level adjustment processing for each broadcast channel on the BS / CS-IF signal supplied via the filter 2. The squelch processing is a process for putting broadcast channels that are determined to be at a noise level (i.e., not broadcasting) into a no-signal state. The level adjustment processing is a process for adjusting the signal of a broadcast channel that is determined not to be at a noise level (i.e., a signal is present) to a predetermined level using the AGC function.

[0021] The signal processing unit 3 includes a diplexer 34, a right-handed processing unit 3R, a left-handed processing unit 3L, and a diplexer 35. The diplexer 34 separates the BS / CS-IF signal supplied via the filter 2 into a right-handed signal and a left-handed signal. The right-handed signal has a frequency in the range of 1032 MHz to 2072 MHz, and is made up of a total of 25 channels including 12 channels of BS right-handed signals and 13 channels of CS right-handed signals.

[0022] The left-handed circularly rotated signals are signals with frequencies in the range of 2234 MHz to 3224 MHz, and are made up of a total of 25 channels, including 12 channels of BS left-handed circularly rotated signals and 13 channels of CS left-handed circularly rotated signals.

[0023] The right-handed circular polarization processing unit 3R executes squelch / level adjustment processing for each broadcast channel of the right-handed circular polarization signal branched by the diplexer . The left-handed circular polarization processing unit 3L executes squelch / level adjustment for each broadcast channel of the left-handed circular polarization signal branched by the diplexer .

[0024] The diplexer 35 multiplexes the right-handed signal supplied from the right-handed processing unit 3R and the left-handed signal supplied from the left-handed processing unit 3L, and supplies the multiplexed signal to the downstream filter 4. Before multiplexing, the diplexer 35 removes signals outside the signal frequency band of the right-handed signal from the signal supplied from the right-handed processing unit 3R, and also removes signals outside the signal frequency band of the left-handed signal from the signal supplied from the left-handed processing unit 3R.

[0025] As shown in FIG. 2, the right-handed rotation processing unit 3R includes a distribution unit 31, a plurality of channel-specific processing units 32, and a mixer 33. The distribution unit 31 distributes the output of the previous stage (that is, the diplexer 34) into signals equal to the number of channels included in the right-handed circularly polarized signal, and supplies the distributed signals to a plurality of channel-specific processing units 32, respectively.

[0026] Each of the channel-specific processing units 32 performs squelch processing and level adjustment processing on the broadcast channel assigned to it, and outputs the results to the mixer unit 33. Different broadcast channels are assigned to the multiple channel-specific processing units 32, respectively.

[0027] The channel-by-channel processing unit 32 includes a first frequency conversion unit 321 , a detection unit 322 , an AGC unit 323 , and a second frequency conversion unit 324 . The first frequency converter 321 converts the frequency of a broadcast channel (hereinafter, assigned channel) assigned by the controller 7 into a signal centered on a processing frequency (hereinafter, processing channel signal) as a target channel. The frequency of the processing channel used by the right-handed processing unit 3R is set outside the signal band of the right-handed signal (i.e., non-signal band), and 300 MHz is used in this embodiment.

[0028] The detection section 322 measures the signal level of the signal on the processing channel supplied from the first frequency conversion section 321, and outputs the result to the control section . The AGC unit 323 adjusts the signal level of the signal output from the second frequency conversion unit 321 according to the detection result in the detection unit 322 so that it becomes a target level LV corresponding to the target channel set by the control unit 7, and outputs the adjusted signal.

[0029] The second frequency converter 324 converts the frequency of the signal level-adjusted by the AGC unit 323 back to the same frequency as the original assigned channel, and outputs the converted signal to the mixer 33 .

[0030] The mixer 33 mixes the signals of the different assigned channels processed by each of the plurality of channel-specific processors 32, and outputs the mixed signal to the subsequent stage (ie, the diplexer 35).

[0031] The left-handed processing unit 3L has the same configuration as the right-handed processing unit 3L, and therefore a description thereof will be omitted. However, the distribution unit 31 in the left-handed processing unit 3L distributes the output of the previous stage (i.e., the diplexer 34) by the number of channels contained in the left-handed signal, and supplies the signals to each of the multiple channel-specific processing units 32. The frequency of the processing channel used in the left-handed processing unit 3L is set outside the signal band of the left-handed signal (i.e., the non-signal band), and 1750 MHz is used in this embodiment.

[0032] Returning to Fig. 1, the filter 4 attenuates signals outside the signal band from the signal output from the signal processor 3. The signals outside the signal band include at least a processing frequency to which a stopped broadcast channel is converted by squelch processing. For example, a high-pass filter is used as the filter 4.

[0033] The amplifier circuit 5 amplifies the output of the filter 4 to a level required depending on the environment in which the channel processor 1 is installed (for example, the characteristics and length of the transmission line from the output terminal 12 to the terminal device 82, etc.).

[0034] According to the operational states of switches 13 to 15, waveform adjustment circuit 6 adjusts the signal output from amplifier circuit 5 to a desired waveform pattern and outputs it from output terminal 12. The waveform pattern refers to the shape pattern of a graph that indicates the signal level at each frequency in the signal domain.

[0035] The signal input to the waveform adjustment circuit 6, i.e., the signal output from the signal processing unit 3, has a basic frequency characteristic (hereinafter referred to as the basic characteristic). The basic characteristic is one of the waveform patterns. The waveform adjustment circuit 6 includes an attenuator (hereinafter referred to as the ATT), a tilt circuit, an inverse tilt circuit, and the like used to process the input signal. The waveform adjustment circuit 6 realizes a plurality of waveform patterns obtained by processing the basic characteristic by switching the characteristics of the ATT, tilt circuit, and inverse tilt circuit in response to the operation of the switches 13 to 15. The operation states of the switches 13 to 15 are also input to the control unit 7 as mode setting information MOD that specifies the waveform pattern.

[0036] The basic characteristic has a characteristic that the signal level increases linearly as the frequency increases in the signal band, as shown in waveform pattern example 1 in Fig. 3. Such basic characteristic is set so that the signal level of the BS / CS-IF signal input to the terminal device 82 via the transmission line is the same for all broadcast channels, assuming that the transmission line from the channel processor 1 to the terminal device 82 has a reference length. In other words, the basic characteristic is set taking into consideration the fact that the transmission line has a characteristic that the amount of attenuation increases as the frequency increases.

[0037] The ATT has a characteristic of uniformly attenuating the entire signal band of the BS / CS-IF signal. The ATT is configured so that the amount of attenuation can be switched by operating switch 13. The tilt circuit has a characteristic that the amount of attenuation increases as the frequency decreases in the signal band, and the amount of attenuation changes linearly with frequency. The tilt circuit is configured so that the slope of the amount of attenuation with respect to frequency can be switched by operating switch 14. The inverse tilt circuit has a characteristic that the amount of attenuation increases as the frequency increases in the signal band, and the amount of attenuation changes linearly with frequency. The inverse tilt circuit is configured so that the slope of the amount of attenuation with respect to frequency can be switched by operating switch 15.

[0038] In other words, the waveform pattern may include a pattern in which only the amount of attenuation is changed without changing the waveform of the basic characteristic. The waveform pattern may include a pattern in which the slope of the signal level with respect to frequency is increased compared to the basic characteristic, as shown in waveform pattern example 3 in Figure 3. The waveform pattern may include a pattern in which the slope of the signal level with respect to frequency is decreased compared to the basic characteristic. The pattern in which the slope of the signal level with respect to frequency is decreased compared to the basic characteristic may include a pattern in which the signal level is constant in the signal band, as shown in waveform pattern example 2 in Figure 3.

[0039] Returning to Figure 1, the control unit 7 outputs a signal that controls the operation of each channel-specific processing unit 32 in accordance with the mode setting information MOD input from the waveform adjustment circuit 6 and the level measurement values ​​input from each channel-specific processing unit 32 belonging to the signal processing unit 3.

[0040] The control unit 7 has a microcomputer equipped with a CPU 71 and a memory 72 such as a ROM or a RAM. The memory 72 stores at least various processing programs for controlling the operation of each channel processing unit 32 belonging to the signal processing unit 3, and the CPU 71 executes the programs to realize various functions. In addition to the programs, the memory 72 stores a lookup table (hereinafter, LUT) 721 used to set a target level LV of the AGC unit 323 of the channel processing unit 32.

[0041] LUT 721 stores level correction values ​​used for correcting signal levels in association with combinations of mode setting information MOD that identifies the operational states of switches 13-15 (and thus the waveform pattern realized by waveform adjustment circuit 6) and broadcast channels.

[0042] The level correction value is used to realize characteristics in which the signal level variation occurring between broadcast channels in the signal output from the output terminal 12 is suppressed. That is, even if the signal level is adjusted to have a desired characteristic by the level adjustment function of the signal processing unit 3, the signal level of the signal output from the output terminal 12 varies between each broadcast channel due to the influence of the subsequent circuit. The subsequent circuit is the filter 4, the amplifier circuit 5, and the waveform adjustment circuit 6. The variation between broadcast channels changes according to the operation state of the switches 13 to 15, that is, the mode setting information MOD. This is because the circuit configuration of the waveform adjustment circuit 6 changes according to the operation state of the switches 13 to 15. In addition, the variation in the signal level differs for each product of the channel processor 1 due to individual differences in the components constituting the subsequent circuit. The level correction value indicated in the LUT 721 is used to suppress such variation.

[0043] It should be noted that the method for realizing the functions included in the control unit 7 does not necessarily need to include software, and some or all of the functions may be realized by hardware.

[0044] [1-2. Processing] [1-2-1. Mode confirmation process] Next, the mode confirmation process executed by the control unit 7 will be described with reference to the flowchart of Fig. 4. The mode confirmation process is repeatedly executed when the control unit 7 is started.

[0045] When the mode confirmation process is started, the control unit 7 acquires the mode setting information MOD from the waveform adjustment circuit 6 in S110. In S120, the control unit 7 stores the mode setting information MOD acquired in S110 in the memory 72, and reads out the level correction values ​​for each broadcast channel according to the mode setting information MOD from the LUT 721, and then ends the process.

[0046] [1-2-2. Noise measurement processing] Next, the noise measurement process executed by the control unit 7 will be described with reference to the flowchart of Fig. 5. The noise measurement process is repeatedly executed when the control unit 7 is started.

[0047] When the noise measurement process is started, in S130, the control unit 7 sets one of the channel-specific processing units 32 as a target processing unit, and sets the target level LV of the output of the AGC unit 323 of the target processing unit to a magnitude that can be regarded as no signal. This is to suppress oscillation by the AGC unit 323. The magnitude that can be regarded as no signal may be, for example, the lower limit value of the target level LV that can be set in the AGC unit 323.

[0048] In S140, the control unit 7 sets the noise measurement channel as the target channel of the target processing unit. Specifically, the center frequency of the noise measurement channel is set to the frequency f T The frequency conversion units 321, 323 of the target processing units are notified of the center frequency of the noise measurement channel, which is a guard band that exists within the signal band. For example, to measure noise in a right-handed signal, 1510 MHz, which is a frequency within the guard band that exists between the BS right-handed signal and the CS right-handed signal, is used. To measure noise in a left-handed signal, 2694.5 MHz, which is a frequency within the guard band that exists between the BS left-handed signal and the CS left-handed signal, is used.

[0049] As a result, in the right-handed processing unit 3R, the first frequency conversion unit 321 of the target processing unit converts the signal of the noise measurement channel centered at 1520 MHz (i.e., the noise of the right-handed signal) of the BS / CS-IF signal into a signal of the processing channel centered at 300 MHz. Also, in the left-handed processing unit 3L, the signal of the noise measurement channel centered at 2694.5 MHz (i.e., the noise of the left-handed signal) is converted into a signal of the processing channel centered at 1750 MHz.

[0050] In S150, the control unit 7 acquires a measurement value from the detection unit 322 of the target processing unit, stores the acquired measurement value as a noise level PN in the memory 72, and ends the process. For example, the noise level PN is an average value of the measurement values ​​in the processing channel.

[0051] [1-2-3. Squelch / level adjustment processing] Next, the squelch / level adjustment process executed by the control unit 7 will be described with reference to the flowchart of Fig. 6. The squelch / level adjustment process is executed repeatedly for all channel-specific processing units 32 individually after the noise measurement / mode confirmation process is executed at least once.

[0052] The channel-specific processing section 32 that is the processing target is called a target processing section, and the channel assigned to the target processing section is called an assigned channel. In S210, the control unit 7 sets the assigned channel as the target channel of the target processing unit. Specifically, the center frequency of the assigned channel is set to the frequency f T The first frequency conversion unit 321 and the second frequency conversion unit 324 of the target processing unit are notified of this.

[0053] As a result, the signal of the assigned channel, among the BS / CS-IF signals, is converted into a signal of the processing channel by the first frequency conversion unit 321 of the target processing unit. In S220, the control unit 7 sets the target level LV of the AGC unit 323 of the target processing unit to a value that can be regarded as no signal, similarly to the previous S130.

[0054] In S230, the control unit 7 acquires a measurement value from the detection unit 322 of the target processing unit, and obtains the acquired measurement value as the input level PI of the assigned channel. In S240, the control unit 7 determines whether or not the input level PI acquired in S230 is greater than the maximum input level value PImax stored in the memory 72. If the control unit 7 determines that PI is greater than PImax, it shifts the process to S250, and if it determines that PI is equal to or less than PImax, it shifts the process to S260.

[0055] In S250, the control unit 7 updates the maximum value PImax of the input level stored in the memory 72 with the input level PI acquired in S230. In S260, the control unit 7 judges whether the input level PI acquired in S230 satisfies PI≧PN+PT and PImax-PI≦15. PN is the noise level stored in the memory 72 in S150. PT is a preset value (e.g., 5 dB). That is, the control unit 7 judges the input level PI to be sufficiently larger than the noise level PN and the difference from the maximum value PImax of the previously measured input level is within an allowable range. If the control unit 7 judges the input level PI to be positive, the control unit 7 determines that the assigned channel is valid and shifts the process to S265, and if the control unit 7 judges the input level PI to be negative, the control unit 7 determines that the assigned channel is invalid (i.e., not transmitting) and shifts the process to S280.

[0056] In S265, the control unit 7 detects whether the signal of the measurement channel is the same as the original assigned channel (i.e., the frequency f T The second frequency converter 324 is set so as to convert the frequency of the first frequency converter 324 to a frequency signal centered on the first frequency converter 324 .

[0057] In S270, the control unit 7 sets the value obtained by adding the level correction value of the assigned channel read out from the LUT 721 to the signal level of the assigned channel in the basic characteristics as the target level LV of the AGC unit 323 of the target processing unit, and proceeds to S280.

[0058] In S280, the control unit 7 acquires the mode setting information MOD from the waveform adjustment circuit 6. In S290, the control unit 7 compares the mode setting information MOD acquired in S280 with the mode setting information MOD stored in the memory 72 to determine whether or not a change has occurred. If the control unit 7 determines that the mode setting information MOD has been changed, it shifts the process to S300, and if it determines that the mode setting information MOD has not been changed, it ends the process. Note that if the mode setting information MOD is not stored in the memory 72, such as immediately after the start-up of the control unit 7, the control unit 7 determines that a change has occurred in S290.

[0059] In S300, the control unit 7 stores the mode setting information MOD acquired in S280 in the memory 72, and reads out the level correction values ​​of each channel according to the mode setting information MOD from the LUT 721, and then ends the process.

[0060] As a result, the signal level of the assigned channel output from the AGC unit 323 is adjusted to the target level LV. In addition, the second frequency conversion unit 324 converts the frequency of the signal output from the AGC unit 323 back to the original frequency of the assigned channel, and supplies the signal to the mixer 33.

[0061] In the channel-specific processing unit 32 for which a negative decision is made in S260, the target level LV of the AGC unit 323 remains set to a magnitude that can be regarded as no signal. In addition, the first frequency conversion unit 321 and the second frequency conversion unit 324 use the same processing module that performs frequency conversion, and the output frequency of the second frequency conversion unit 324 remains the frequency of the measurement channel used in the first frequency conversion unit 321. Therefore, the signal of the stopped broadcast channel remains in the processing channel without being frequency converted to the original assigned channel by the second frequency conversion unit 324, and has a magnitude that can be regarded as no signal.

[0062] The mixing unit 33 mixes the signals that have been subjected to squelch / level adjustment processing and are output from each channel-specific processing unit 32, and supplies a BS / CS-IF signal having basic characteristics corrected by a level correction value to the downstream filter 4.

[0063] [1-3. Operation] As shown in FIG. 7, the channel processor 1 distributes the BS / CS-IF signal in a distribution section 31 into the same number of channels as the number of broadcast channels, and supplies each of the distributed signals to a channel-specific processing section 32 .

[0064] In the channel-specific processing unit 32, the signal of the assigned channel, which is the broadcast channel assigned to itself, is frequency-converted to a processing channel (i.e., a channel centered on 300 MHz in the right-handed processing unit 3R and 1750 MHz in the left-handed processing unit 3L) by the first frequency conversion unit 321. Regardless of the frequency of the assigned channel, all assigned channels are converted to the signal of the processing channel.

[0065] Based on the input level PI detected by the detector 322, it is determined whether the assigned channel is valid or out of service. For a channel determined to be valid (hereinafter, valid channel), the target level LV of the AGC unit 323 is set based on the signal level of the assigned channel in the reference characteristic and the level correction value corresponding to the mode setting information MOD read from the LUT 721. In addition, the output frequency of the second frequency conversion unit 324 is set to the original frequency of the assigned channel.

[0066] For a channel determined to be out of service (hereinafter, out-of-service channel), the target level LV of the AGC unit 323 is set to a level that can be regarded as no signal. Also, the output frequency of the second frequency conversion unit 324 remains at the frequency of the processing channel.

[0067] As a result, the signal of the valid channel is level-adjusted to the target level LV by the AGC unit 323, and converted to the original frequency of the assigned channel by the second frequency conversion unit 324. The signal of the stopped channel is adjusted to a level that can be regarded as no signal by the AGC unit 323, and remains in the processing channel without being converted to the original frequency of the assigned channel.

[0068] The signals of each broadcast channel processed by the channel-specific processing units 32 are mixed in the mixer 33. The diplexer 35 removes signals other than right-handed signals from the signal output from the mixer 33 of the right-handed processing unit 3R, removes signals other than left-handed signals from the signal output from the mixer 33 of the left-handed processing unit 3L, and then mixes both signals. The BS / CS-IF signal, which is the signal mixed by the diplexer 35, has a waveform in which the basic characteristics have been corrected by a level correction value. The signals of the stopped channels that remain in the processing channel are removed by the diplexer 35.

[0069] [1-4. Correspondence of terms] In this embodiment, the AGC unit 323 corresponds to the automatic gain control unit of the present disclosure. In this embodiment, the diplexer 34 corresponds to the branching circuit of the present disclosure, and the diplexer 35 corresponds to the filter and multiplexing circuit of the present disclosure. In this embodiment, the steps S230 to S260 of the process executed by the control unit 7 correspond to the determination unit of the present disclosure, and S220 and S270 correspond to the level setting unit of the present disclosure.

[0070] [1-5.Effects] According to the first embodiment described above in detail, the following effects are achieved. (1a) The channel processor 1 does not output the signal (i.e., noise) of the out-of-service channel. This improves the signal-to-noise ratio of the BS / CS-IF signal output via the channel processor 1, and also prevents the out-of-service channel from affecting other channels.

[0071] (1b) According to the channel processor 1, the AGC unit 323 of the channel processing unit 32 that processes the out-of-service channel does not go to full gain, so that oscillation due to noise in the out-of-service channel can be suppressed.

[0072] (1c) Since the processing of the signal processing unit 3 is divided into the right-handed processing unit 3R and the left-handed processing unit 3L and executed, the processing load of each of the processing units 3R and 3L can be reduced. [2. Second embodiment] [2-1. Differences from the first embodiment] The second embodiment has a basic configuration similar to that of the first embodiment, and therefore differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

[0073] In the first embodiment described above, the left-handed circularly polarized signal separated by the diplexer 34 is directly input to the left-handed circularly polarized processing unit 3L. In contrast, the second embodiment differs from the first embodiment in that a frequency-converted left-handed circularly polarized signal is input to the left-handed circularly polarized processing unit 3L.

[0074] [2-2. Signal processing section / control section] In this embodiment, a signal processing unit 3a and a control unit 7a have configurations different from those of the signal processing unit 3 and the control unit 7 in the first embodiment, and therefore the following description will focus on these differences.

[0075] As shown in FIG. 8, the signal processing unit 3a includes a downconverter 36, an upconverter 37, and an oscillator 38 in addition to diplexers 34 and 35, a right-handed circular processing unit 3R, and a left-handed circular processing unit 3L.

[0076] The down converter 36 converts the frequency of the left-handed circularly polarized signal separated by the diplexer 34 using a local oscillation signal generated by an oscillator 38 so that the left-handed circularly polarized signal has substantially the same signal band as the right-handed circularly polarized signal.

[0077] In order to convert the left-handed signal to the same signal as the right-handed signal, it is necessary to set the local oscillation signal to 1192 MHz or 4256 MHz. However, when 1192 MHz is used as the local oscillation signal, the frequency of the local oscillation signal overlaps with the signal band of the converted left-handed signal (i.e., the signal band of the right-handed signal) of 1032 to 2072 MHz, which is not practical. Therefore, the local oscillation signal needs to be set to a frequency lower than the signal band of the right-handed signal, for example, 1000 MHz. In addition, when 4256 MHz is used as the local oscillation signal, the order of the frequencies is reversed, so that it is necessary to set the processing channel and perform level adjustment processing taking this into consideration. In addition, the frequency of the local oscillation signal is not limited to 1000 MHz or 4256 MHz, and it is sufficient that it is set so that at least a part of the signal band of the left-handed signal after frequency conversion overlaps with the signal band of the right-handed signal.

[0078] The left-handed circular polarization processing unit 3L executes squelch / level adjustment for each broadcast channel of the left-handed circular polarization signal frequency-converted by the down-converter . The up-converter 37 uses a local oscillation signal generated by an oscillator 38 to frequency-convert the signal output from the left-handed circular polarization processing unit 3L to the original signal band of the left-handed circular polarization signal.

[0079] The diplexer 35 combines the right-handed signal that has been squelched and level adjusted and is supplied from the right-handed processing unit 3R with the left-handed signal that has been squelched and level adjusted and is supplied from the left-handed processing unit 3L via the upconverter 37, and supplies the combined signal to the downstream filter 4.

[0080] The control unit 7a performs the process of instructing the oscillator 38 to start and stop, in addition to the process performed by the control unit 7. [2-3. Effects] According to the second embodiment described above in detail, in addition to the effects (1a) to (1c) of the first embodiment described above, the following effect is also obtained.

[0081] (2a) In this embodiment, the left-handed processing unit 3L can process signals of approximately the same frequency as the right-handed processing unit 3R, so that both processing units 3R and 3L can have the same circuit configuration.

[0082] 3. Other embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0083] (3a) In the above embodiment, one of the channel-specific processing units 32 used for processing the assigned channels is also used for measuring the noise level PN. However, a dedicated channel-specific processing unit 32 may be provided for use in measuring the noise level PN.

[0084] (3b) In the above embodiment, the channel-specific processing unit 32 is configured to perform processing in the order of the AGC unit 323 and the second frequency conversion unit 324. However, the processing may be performed in the reverse order, that is, in the second frequency conversion unit 324 and the AGC unit 323.

[0085] (3c) In the above embodiment, the processing frequency is set to a frequency lower than the signal band, but it may be set to a frequency within a guide band within the signal band. In this case, the filter 4 may be configured to suppress not only signals outside the signal band but also signals in the guard band. Note that signals outside the signal band and signals in the guard band are both referred to as non-signal band signals.

[0086] (3d) In the above embodiment, the signal processor 3 is configured to split the BS / CS-IF signal into two, a right-handed signal and a left-handed signal, which are processed separately by the right-handed processor 3R and the left-handed processor 3L, but the right-handed signal and the left-handed signal may be processed by one processor. Also, the BS / CS-IF signal may be split into three or more signals, which are processed by three or more processors. In this case, for example, the signal may be split into four, a BS right-handed signal, a CS right-handed signal, a B left-handed signal S, and a CS left-handed signal, which are processed.

[0087] (3e) In the second embodiment, only the left-handed signal input to the left-handed processing unit 3L is frequency-converted, but the right-handed signal input to the right-handed processing unit 3R may also be frequency-converted. In this case, for example, the right-handed signal and the left-handed signal can be converted to a lower frequency, so that the right-handed processing unit 3R and the left-handed processing unit 3L can be configured more simply.

[0088] (3f) In the above embodiment, the signal processing units 3, 3a are configured to process analog signals. However, the signal processing units 3, 3a may be configured to perform A / D conversion of input signals and D / A conversion of output signals from the signal processing units 3, 3a to process digital signals.

[0089] (3g) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0090] (3h) In addition to the channel processor 1 described above, the present disclosure can also be realized in various forms, such as a system including the channel processor 1 as a component, a program for causing a computer to function as the control unit 7 of the channel processor 1, a non-transient physical recording medium such as a semiconductor memory on which this program is recorded, and a squelch method. [Explanation of symbols]

[0091] 1...channel processor, 2, 4...filter, 3, 3a...signal processing unit, 3R...right-hand rotation processing unit, 3L...left-hand rotation processing unit, 5...amplification circuit, 6...waveform adjustment circuit, 7, 7a...control unit, 11...input terminal, 12...output terminal, 13-15...switch, 31...distribution unit, 32...channel-specific processing unit, 33...mixing unit, 34, 35...diplexer, 36...downconverter, 37...upconverter, 38...oscillator, 71...CPU, 72...memory, 81...antenna, 82...terminal device, 321...second frequency conversion unit, 321...first frequency conversion unit, 322...detection unit, 323...AGC unit, 324...second frequency conversion unit.

Claims

1. a signal processing unit configured to process a BS / CS-IF signal input from an input terminal for each channel included in the BS / CS-IF signal; a filter configured to set at least one of a band other than a signal band to be processed by the signal processing unit and a guard band within the signal band as a non-signal band, and to suppress signals in the non-signal band from the signal output from the signal processing unit and output the signal; A control unit that controls an operation of the signal processing unit; Equipped with The signal processing unit includes: a first frequency conversion unit configured to convert a signal of the target channel into a processing channel set in the non-signal band, the first frequency conversion unit being configured to convert the signal of the target channel into a processing channel set in the non-signal band; a second frequency converter configured to frequency convert the signal of the processing channel to one of the channels belonging to the signal band; an automatic gain adjustment unit configured to adjust the signal level of the target channel to a set target level; Equipped with The control unit is a determination unit configured to determine whether the target channel is out of service based on a signal level of the processing channel; a conversion setting unit configured to set the second frequency conversion unit so that a signal of the target channel determined by the determination unit to be in a stopped state remains in the non-signal band; Equipped Channel processor.

2. 2. A channel processor according to claim 1, comprising: The control unit is a level setting unit configured to set the target level of the automatic gain control unit, which adjusts the level of the target channel determined by the determination unit to be in a stopped state, to a level that can be regarded as no signal; The channel processor further comprises:

3. 3. A channel processor according to claim 1 or claim 2, comprising: The signal processing unit includes: a splitter circuit configured to split the BS / CS-IF signal into a right-handed signal and a left-handed signal; A right-handed rotation processing unit configured to process the right-handed signal branched by the branching circuit; A left-handed rotation processing unit configured to process the left-handed signal branched by the branching circuit; a multiplexing circuit configured to multiplex and output the signals output from the right-handed rotation processing unit and the left-handed rotation processing unit; Equipped with The right-handed processing unit and the left-handed processing unit each include the first frequency conversion unit, the second frequency conversion unit, and the automatic gain adjustment unit, The non-signal band is set individually for each of the right-handed processing unit and the left-handed processing unit. Channel processor.

4. 4. A channel processor according to claim 3, comprising: The signal processing unit includes: A down converter configured to convert the left-handed signal into a signal whose signal band overlaps at least a portion with the right-handed signal, and input the signal to the left-handed processing unit; An up-converter configured to convert the signal output from the left-handed processing unit into a signal in an original signal band of the left-handed signal; The channel processor further comprises:

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