JP2008167228A - Diversity receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a deterioration of a reception quality to a minimum in a reception environment where an interfering signal is mixed in a band of a desired digital broadcasting signal as well. <P>SOLUTION: A subtractor 4a inputs an output signal 2a' of a channel selector 2a and an output signal 2b' of a channel selector 2b via a signal corrector 6a and subtracts these. An interfering signal detector 5a detects an electric power of the interfering signal included in the output signal of the subtractor 4a. Correction information on a gain and phase is supplied to the signal corrector 6a so that the detected electric power is decreased. The signal corrector 6a corrects the gain and phase of the output signal 2b' of the channel selector 2b in accordance with the supplied correction information, and supplies the result to the subtractor 4a. As a result, the interfering signal included in the output signal of the subtractor 4a is removed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diversity receiver, and more particularly to a diversity receiver that can receive high-quality signals even in a reception environment in which an interference signal is included in a band of a desired digital broadcast signal.

  Japanese terrestrial digital broadcasting employs an orthogonal frequency division division (OFDM) system as a modulation system. The OFDM system is a system in which a large number of orthogonal carriers (subcarriers) are provided, and data is assigned to the amplitude and phase of each subcarrier for digital modulation. The OFDM system is strong in multipath and can be subjected to time interleaving, and therefore has a feature that it is relatively excellent in reception on a mobile body. However, in order to realize stable reception even when traveling in an environment where remarkably multipath and fading occur, the mobile reception tolerance using only the above means is insufficient. Therefore, a so-called diversity reception technique is used in which digital broadcasting signals are received using a plurality of antennas, and stable reception is realized by combining the received signals.

  As a diversity combining method, a selective combining method, an equal gain combining method, and a maximum ratio combining method are known. The selective combining method is a combining method that selects only the antenna having the highest received power and does not use signals from other antennas. The equal gain combining method is a method of combining signals with the same phase from each antenna. The maximum ratio combining method is a method in which the phases of the signals from the respective antennas are made the same, and a weight proportional to the received power is added to each antenna for combining (for example, see Patent Document 1).

  In addition, as a method of using diversity when receiving a digital broadcast signal, for example, the received digital broadcast signal is converted from the time domain to the frequency domain, a signal for each subcarrier is extracted, and a signal assigned to each subcarrier A method of demodulating data and performing diversity combining processing on the obtained demodulated data of each subcarrier in units of subcarriers is disclosed (see Patent Document 2).

JP-A-9-284191 JP 2001-156738 A

  However, in the conventional general diversity receiver, if the interference signal is received within the band of the desired digital broadcast signal due to the peripheral device of the receiver or the receiver itself, etc., the disturbed digital broadcast Diversity synthesis and demodulation processing are performed using the signal, and there is a problem that the quality of the demodulated digital signal deteriorates.

  In the conventional combining method, the magnitude of received power is used as an evaluation index when combining or selecting signals of a plurality of systems. That is, priority is given to the signal of the system having the maximum power, and the signal is combined and selected. As a result, when a specific frequency is disturbed, demodulation is performed with priority given to the signal of the disturbed system, and an error occurs in the demodulated data.

  The present invention has been made in order to solve the above-described problems, and it is possible to minimize degradation of reception quality even in a reception environment in which an interference signal is mixed in a desired digital broadcast signal band. It is to provide a diversity receiver.

  The diversity receiver of the present invention converts the received first and second high-frequency signals into intermediate frequency signals and selects the first and second signals of the desired channel. A channel selection unit, a signal correction unit that performs signal correction on the first signal selected by the first channel selection unit, an output signal of the signal correction unit, and a second signal selected by the second channel selection unit. The subtracting or adding operation unit, the interfering signal detecting unit for detecting the interfering signal included in the output signal of the arithmetic unit and controlling the correction amount of the signal correcting unit, and the first and second tuning units are selected. A synthesizing / demodulating unit for synthesizing and demodulating the first and second signals that have been stationed and the output signal of the arithmetic unit, and the interfering signal detecting unit applies to the signal correcting unit so that the detected interfering signal decreases Supply signal correction information.

  Also, the diversity receiver of the present invention converts the received first and second high-frequency signals into intermediate frequency signals and selects the first and second signals of the desired channel. Two tuning units, a local oscillator that supplies a local oscillation signal for frequency conversion to the first and second tuning units, a phase correction unit that performs phase correction on the local oscillation signal supplied by the local oscillator, A subtracting or adding operation for the first signal selected by the channel selecting unit and the second signal selected by the second channel selecting unit, and detecting an interference signal included in the output signal of the calculating unit And combining and demodulating the interference signal detection unit for controlling the correction amount of the phase correction unit, the first and second signals selected by the first and second channel selection units, and the output signal of the calculation unit. A jamming signal detector, the phase of the jamming signal detector so that the jamming signal detected is reduced. Supplying the phase correction information to the positive portion.

  According to the present invention, it is possible to minimize degradation of reception quality even in a reception environment in which an interference signal is mixed in the band of a desired digital broadcast signal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a first embodiment (embodiment 1) of a diversity receiver according to the present invention. 1a and 1b are high-frequency signal input units, 2a and 2b are channel selection units, 3 is a local oscillator, 4a and 4b are subtraction units, 5a and 5b are interference signal detection units, 6a and 6b are signal correction units, and 7a to 7d are A / D conversion unit, 8a to 8d are orthogonal demodulation units, 9a to 9d are FFT units, 10 is a synthesis / demodulation unit, 13 is a decoder, 14 is a control unit, and 15 is a memory.

  In FIG. 1, high-frequency signal input units 1a and 1b receive digital broadcast signals and supply them to channel selection units 2a and 2b. The local oscillator 3 generates a local oscillation signal corresponding to the frequency channel of a desired digital broadcast signal and supplies it to the channel selection units 2a and 2b. The channel selection unit 2a multiplies the digital broadcast signal supplied from the high-frequency signal input unit 1a by the local oscillation signal supplied from the local oscillator 3, and converts the frequency into a digital broadcast signal having an intermediate frequency. The output signal 2a 'of the channel selection unit 2a is supplied to the A / D conversion unit 7a, the subtraction unit 4a, and the signal correction unit 6b. On the other hand, the channel selection unit 2b multiplies the digital broadcast signal supplied from the high-frequency signal input unit 1b by the local oscillation signal supplied from the local oscillator 3, and converts the frequency into a digital broadcast signal having an intermediate frequency. The output signal 2b 'of the channel selection unit 2b is supplied to the A / D conversion unit 7d, the subtraction unit 4b, and the signal correction unit 6a. The channel selection units 2a and 2b can be provided with a filter (not shown) that extracts only a band of a desired digital broadcast signal, and can remove unnecessary signals other than the desired digital broadcast signal.

  The A / D conversion units 7a to 7d convert the supplied analog signals into digital signals and supply the digital signals to the orthogonal demodulation units 8a to 8d, respectively. The quadrature demodulation units 8a to 8d convert the supplied digital signals into complex baseband signals and supply them to the FFT units 9a to 9d, respectively. The FFT units 9 a to 9 d convert the supplied complex baseband signal from the time domain to the frequency domain by FFT (Fast Fourier Transform), and supply the signal data of each subcarrier to the synthesis / demodulation unit 10. The synthesizing / demodulating unit 10 performs diversity combining and demodulation processing based on the supplied signal data of the FFT units 9a to 9d, and outputs a digital signal. This signal is further decoded by the decoder 13 to become a video / audio signal. In the diversity combining method, a selective combining method for selecting a signal with the largest received power, an equal gain combining method for combining signals with the same phase, the same phase for each signal, and proportional to the received power A maximum ratio combining method in which a weight is added to each signal and combined is appropriately used.

  The subtraction unit 4a subtracts the output signal 2a 'from the channel selection unit 2a and the output signal from the signal correction unit 6a, and supplies the result to the A / D conversion unit 7b. The interfering signal detector 5a detects an interfering signal generated due to a peripheral device of the receiving apparatus or an interfering radio wave of the receiving apparatus itself. Therefore, the interference signal detection unit 5a calculates the power of each subcarrier supplied from the FFT unit 9b, and determines that the subcarrier having the largest power is disturbed. Further, the interference signal detection unit 5a is provided with a threshold determination circuit for determining the power of each subcarrier, compares the power of each subcarrier supplied from the FFT unit 9b with the threshold, and subcarriers exceeding the threshold interfere with each other. You may judge that you are receiving.

  Then, the interference signal detection unit 5a performs signal correction on at least one correction amount (hereinafter referred to as signal correction information) of gain and phase so that the power of the interference signal included in the output signal of the subtraction unit 4a is reduced. To the unit 6a. The signal correction unit 6a corrects the gain and phase of the output signal 2b 'of the channel selection unit 2b according to the supplied signal correction information, and supplies the corrected signal to the subtraction unit 4a. Here, the interference signal detection unit 5a repeatedly supplies the signal correction information to the signal correction unit 6a so that the power of the interference signal included in the output signal of the subtraction unit 4a becomes a minimum value.

  On the other hand, the subtraction unit 4b subtracts the output signal 2b 'from the channel selection unit 2b and the output signal from the signal correction unit 6b, and supplies the result to the A / D conversion unit 7c. The interference signal detection unit 5b detects an interference signal included in the output signal of the subtraction unit 4b based on the signal data of each subcarrier supplied from the FFT unit 9c. The interference signal detection unit 5b corrects the output signal 2a ′ of the channel selection unit 2a supplied to the signal correction unit 6b, and the power of the interference signal included in the output signal of the subtraction unit 4b is a minimum value. The signal correction information is repeatedly supplied to the signal correction unit 6b. The signal correction unit 6b corrects the gain and phase of the output signal 2a 'of the channel selection unit 2a according to the supplied signal correction information, and supplies the corrected signal to the subtraction unit 4b.

  As described above, in the first embodiment, by providing the interference detection units 5a and 5b, the signal correction units 6a and 6b, and the subtraction units 4a and 4b, the FFT units 9b and 9c output a new signal from which the interference signal is removed. There is a special feature. Further, by increasing the number of signal systems to 4 and inputting them to the synthesizing / demodulating unit 10 and performing optimum signal processing, a higher quality signal can be obtained.

  Here, the interference signal detectors 5a and 5b can operate independently or in cooperation with each other. First, when the number of interference signals detected in each of the interference signal detectors 5a and 5b is one, the interference signal detectors 5a and 5b perform control so that the power of the interference signal detected in each interference signal detector is minimized. Further, when there are a plurality of interference signals detected in each of the interference signal detectors 5a and 5b, the interference signal detectors 5a and 5b are controlled so that the total power of the plurality of interference signals detected in each interference signal detector is minimized. .

  Further, the interference signal detection unit 5a removes the interference signal with the highest power detected, and the interference signal detection unit 5b removes the interference signal with the highest power excluding the interference signal removed by the interference signal detection unit 5a. It is also possible to control in cooperation. This makes it possible to remove two different interference signals. Further, when receiving a hierarchically transmitted digital broadcast, the interference signal detectors 5a and 5b detect an interference signal included in the band of each layer, and the interference included in the band of the layer being received. It can also be controlled to preferentially remove the signal. For example, a jamming signal in each band of 1-segment broadcasting and 12-segment broadcasting is detected, and control is performed to remove the jamming signal in 1-segment broadcasting band while receiving 1-segment broadcasting, and while receiving 12-segment broadcasting. Control is performed to remove interfering signals within the 12 segment broadcast band. In addition, considering the occurrence of interference interference on the same channel in analog broadcasting, a video carrier band and an audio carrier band are provided at the frequency positions of the video carrier and audio carrier of the analog signal, and the interference signals detected in these bands are given priority. You may control to remove.

  The interference signal detection units 5 a and 5 b store the generated signal correction information for each channel selection in the memory 15. When the same channel is selected again, the control unit 14 can read out the signal correction information stored in the memory 15 and supply it to the signal correction units 6a and 6b to remove the interference signal. Thus, if the interference signal mixed in the receiving device is the same as that at the time of the previous channel selection, the interference signal can be easily removed by the signal correction information stored in the memory 15. Detection time can be shortened or omitted. In particular, when receiving a time-division multiplexed signal in which a plurality of channels are switched every short time and transmitted, the optimum signal correction information for each channel can be stored in a memory to efficiently remove the interference signal. it can.

  By the way, the interference signal is generated from peripheral devices of the receiving device or the receiving device itself and mixed in the high-frequency signal input units 1a and 1b. The interference signals mixed in the high-frequency signal input units 1a and 1b are frequency-converted to an intermediate frequency in the channel selection units 2a and 2b, but the local oscillation signals supplied from the common local oscillator 3 are used. The frequency of the interference signal output from the same frequency. In order to completely eliminate the interference signal included in the output signals of the subtraction units 4a and 4b by correcting the gain and phase of the signals input to the signal correction units 6a and 6b by the interference signal detection units 5a and 5b, respectively. The frequencies of the carrier interference signals output from the channel selection units 2a and 2b need to match. The configuration of the present embodiment satisfies this.

  FIG. 2 is a diagram illustrating a state of the interference signal before and after performing the interference signal removal processing. (A) is an interference signal a included in the output signal 2a 'of the channel selection unit 2a, and (b) is an interference signal b included in the output signal 2b' of the channel selection unit 2b. (C) is a jamming signal included in the output signal of the subtracting unit 4a. The jamming signal c1 is before the jamming signal removal processing, and the jamming signal c2 is after the jamming signal removal processing. (D) is a jamming signal included in the output signal of the subtracting section 4b. The jamming signal d1 is before the jamming signal removal processing, and the jamming signal d2 is after the jamming signal removal processing. (E) is a jamming signal included after the synthesis / demodulation unit 10 combines the output signals of the four FFT units. The jamming signal e1 is before the jamming signal removal processing, and the jamming signal e2 is the jamming signal. This is after the removal process. However, although the output signal of the FFT unit is a digital signal, it is shown here as an analog signal waveform for the sake of explanation.

  In FIG. 2, the subtracting units 4a and 4b subtract the two interfering signals a and b as they are before performing the interfering signal removing process. Therefore, the output signals of the subtracting units 4a and 4b include the interfering signal c1. , D1 are included without decreasing. Therefore, the synthesizing / demodulating unit 10 generates an interference signal e1 having an increased amplitude by combining the four interference signals a, b, c1, and d1, and performs a demodulation process using a signal including the interference signal e1. As a result, errors occur in the demodulated data.

  On the other hand, after the interference signal removal processing is performed, the interference signals c2 and d2 included in the output signals of the subtracting units 4a and 4b are removed or sufficiently suppressed. Therefore, the synthesis / demodulation unit 10 synthesizes the four interference signals a, b, c2, and d2 to generate an interference signal e2 having a smaller amplitude than the interference signal e1 before the removal process. By performing demodulation processing using a signal including the interference signal e2, it is possible to reduce data errors after demodulation compared to before the interference signal removal processing.

  FIG. 3 is a diagram for explaining a method for removing an interference signal, and as an example, a case where a single carrier interference signal is mixed will be described. Here, the removal of the interference signal in the subtraction unit 4a shown in FIG. The interference signal a supplied to the subtraction unit 4a is a carrier interference signal mixed in the output signal 2a ′ from the channel selection unit 2a, and the interference signal b is a carrier mixed in the output signal from the signal correction unit 6a. Interfering signal. The interference signal a and the interference signal b have the same frequency, but the amplitude is shifted by ΔA and the phase is shifted by Δθ. At this time, an interference signal c1 obtained by subtracting the interference signal a and the interference signal b appears in the output signal of the subtraction unit 4a. The interference signal detection unit 5a generates information for correcting the amplitude and phase of the interference signal b, and repeatedly corrects the signal while sequentially correcting the signal correction information until the power of the interference signal c1 becomes the minimum value. To the unit 6a. The signal correction unit 6a corrects the amplitude and phase of the output signal 2b 'of the channel selection unit 2b according to the supplied signal correction information, thereby correcting the amplitude and phase of the interference signal b. When the correction is made so as to eliminate the amplitude difference ΔA and the phase difference Δθ between the interference signals a and b, the interference signals a and b cancel each other out in the subtracting unit 4a, and the interference signal c2 in FIG. Can be removed and output.

  As described above, in the first embodiment, even in a reception environment in which an interference signal is mixed in the band of a desired digital broadcast signal, the interference signal is removed and demodulation processing is performed using a high-quality digital broadcast signal. By doing so, it is possible to improve the reception quality.

  In FIG. 1, the interference signal elimination system may be one system. That is, the subtractor 4b, the interference signal detection unit 5b, the signal correction unit 6b, the A / D conversion unit 7c, the quadrature demodulation unit 8c, and the FFT unit 9c are deleted, and the input signal to the synthesis / demodulation unit 10 is converted into the FFT unit 9a, You may make it the structure set as 3 inputs from 9b and 9d.

  FIG. 4 is a block diagram showing a configuration of a second embodiment (embodiment 2) of the diversity receiver according to the present invention. In the second embodiment, interference signal detectors 5c and 5d and signal analyzers 11a and 11b are newly provided. Elements having the same functions as those in the first embodiment (FIG. 1) are denoted by the same reference numerals and description thereof is omitted.

  The signal analysis unit 11a includes a bandpass filter that is narrower than the bandwidth of the digital broadcast signal and has a variable pass center frequency, and scans with the bandpass filter over the bandwidth of the output signal of the subtraction unit 4a. Thus, power is calculated for each narrow band section of the output signal of the subtracting unit 4a.

  The interference signal detection unit 5c determines that the narrow band section having the highest power among the powers of the respective narrow band sections supplied from the signal analysis unit 11a is disturbed. In addition, the interference signal detection unit 5c includes a threshold determination circuit that determines the power of each narrowband section, compares the power of each narrowband section supplied from the signal analysis unit 11a with the threshold, and narrowbands exceeding the threshold It may be determined that the section is disturbed.

  Then, the interference signal detection unit 5c supplies the signal correction information to the signal correction unit 6a so that the power of the interference signal included in the output signal of the subtraction unit 4a is reduced. The signal correction unit 6a corrects the gain and phase of the output signal 2b 'of the channel selection unit 2b according to the supplied signal correction information, and supplies the corrected signal to the subtraction unit 4a. Here, the interference signal detection unit 5c supplies the signal correction information to the repeated signal correction unit 6a while sequentially correcting the signal correction information until the power of the interference signal included in the output signal of the subtraction unit 4a becomes the minimum value.

  The same applies to the operations of the signal analysis unit 11b, the interference signal detection unit 5d, and the signal correction unit 6b.

  In the second embodiment as well, the interference signal detection units 5c and 5d can operate independently or in cooperation with each other. When the number of jamming signals detected in each of the jamming signal detection units 5c and 5d is one, the jamming signal detection units 5c and 5d perform control so that the power of the jamming signal detected in each jamming signal detection unit is minimized. Further, when there are a plurality of interference signals detected in each of the interference signal detection units 5c and 5d, the interference signal detection units 5c and 5d perform control so that the total power of the plurality of interference signals detected in each interference signal detection unit is minimized.

  Further, the interference signal detection unit 5c removes the interference signal with the highest power detected, and the interference signal detection unit 5d removes the interference signal with the highest power excluding the interference signal removed by the interference signal detection unit 5c. It can also be controlled. This makes it possible to remove two different interference signals. Further, when receiving a hierarchically transmitted digital broadcast, the interference signal detectors 5c and 5d detect an interference signal included in the band of each layer, and the interference included in the band of the layer being received. It can also be controlled to preferentially remove the signal.

  The interference signal detectors 5 c and 5 d store the generated signal correction information for each channel selection in the memory 15. When the same channel is selected again, the control unit 14 can read out the signal correction information stored in the memory 15 and supply it to the signal correction units 6a and 6b to remove the interference signal. Thus, if the interference signal mixed in the receiving device is the same as the previous channel selection, the interference signal can be removed by the signal correction information stored in the memory, and the detection time of the interference signal can be reduced. Can be shortened or omitted.

  As described above, in the second embodiment, the signal analyzers 11a and 11b are provided and the output signals of the subtractors 4a and 4b are analyzed to detect and remove the interference signal. An effect can be obtained.

  Furthermore, in the second embodiment, signal analysis units 11a and 11b for analyzing the outputs of the subtraction units 4a and 4b are arranged in front of the A / D conversion units 7b and 7c. Usually, each A / D converter, each quadrature demodulator, and each FFT unit are often configured in a common LSI, and can be realized without changing the LSI when using such an LSI, which is advantageous in terms of mounting. It becomes.

  In FIG. 4, the interference signal elimination system may be one system. That is, the subtractor 4b, the interference signal detection unit 5d, the signal correction unit 6b, the A / D conversion unit 7c, the quadrature demodulation unit 8c, and the FFT unit 9c are deleted, and the input signal to the synthesis / demodulation unit 10 is converted to the FFT unit 9a, You may make it the structure set as 3 inputs from 9b and 9d.

  FIG. 5 is a block diagram showing the configuration of the third embodiment (third embodiment) of the diversity receiver according to the present invention. In the third embodiment, the signal correction units 6a and 6b are deleted, and interference signal detection units 5e and 5f and phase correction units 12a and 12b are newly provided. Elements having the same functions as those in the first embodiment (FIG. 1) are denoted by the same reference numerals and description thereof is omitted.

  The subtraction unit 4a subtracts the output signal 2a 'from the channel selection unit 2a and the output signal 2b' from the channel selection unit 2b, and supplies the result to the A / D conversion unit 7b. The interference signal detection unit 5e calculates the power of each subcarrier supplied from the FFT unit 9b, and determines that the subcarrier having the highest power is disturbed. The interference signal detection unit 5e also includes a threshold determination circuit that determines the power of each subcarrier, compares the power of each subcarrier supplied from the FFT unit 9b with the threshold, and subcarriers exceeding the threshold interfere with each other. You may judge that you are receiving.

  Then, the interference signal detection unit 5e supplies a phase correction amount (hereinafter referred to as phase correction information) to the phase correction unit 12a so that the power of the interference signal included in the output signal of the subtraction unit 4a is reduced. . The phase correction unit 12a corrects the phase of the local oscillation signal according to the supplied phase correction information and supplies the corrected signal to the channel selection unit 2a. Here, the interference signal detection unit 5e sequentially corrects the phase correction information and supplies it to the phase correction unit 12a repeatedly until the power of the interference signal included in the output signal of the subtraction unit 4a becomes a minimum value.

  By performing the phase correction of the local oscillation signal supplied to the tuning unit 2a, the phase of the output signal 2a 'of the tuning unit 2a can be adjusted, that is, the phase of the interference signal 2a' can be adjusted. As a result, an interference signal included in the output signal of the subtracting unit 4a can be removed.

  On the other hand, the subtraction unit 4b subtracts the output signal 2a 'from the channel selection unit 2a and the output signal 2b' from the channel selection unit 2b, and supplies the result to the A / D conversion unit 7c. The interference signal detection unit 5f detects an interference signal included in the output signal of the subtraction unit 4b based on the signal data of each subcarrier supplied from the FFT unit 9c. Then, the interference signal detection unit 5f supplies the phase correction information to the phase correction unit 12b so that the power of the interference signal included in the output signal of the subtraction unit 4b is reduced. The phase correction unit 12b corrects the phase of the local oscillation signal according to the supplied phase correction information, and supplies the corrected signal to the channel selection unit 2b. As a result, the interference signal included in the output signal of the subtracting unit 4b can be removed.

  Here, the interference signal removal processing by the interference signal detection unit 5e and the interference signal removal processing by the interference signal detection unit 5f are alternately and repeatedly executed so that the power sum of each interference signal is minimized. You may do it. That is, when the interference signal detection unit 5e performs the interference signal removal process, the interference signal detection unit 5f does not perform the interference signal removal process, and when the interference signal detection unit 5f performs the interference signal removal process, The interference signal removal processing by the interference signal detector 5e is not performed. Thereby, the interference signal removal processing by the interference signal detection unit 5e and the interference signal detection unit 5f can avoid interference with each other and converge to an optimum state.

  In the third embodiment, the interference signal detection units 5e and 5f can operate independently or in cooperation with each other. When the number of jamming signals detected in each of the jamming signal detectors 5e and 5f is one, the jamming signal detectors 5e and 5f perform control so that the power of the jamming signal detected in each jamming signal detector is minimized. In addition, when there are a plurality of interference signals detected in each of the interference signal detection units 5e and 5f, the interference signal detection units 5e and 5f perform control so that the total power of the plurality of interference signals detected in each interference signal detection unit is minimized. .

  Further, the interference signal detection unit 5e removes the interference signal with the highest power detected, and the interference signal detection unit 5f removes the interference signal with the highest power excluding the interference signal removed by the interference signal detection unit 5e. It can also be controlled. This makes it possible to remove two different interference signals. Further, when receiving a hierarchically transmitted digital broadcast, the interference signal detectors 5e and 5f detect an interference signal included in the band of each layer, and the interference included in the band of the layer being received. It can also be controlled to preferentially remove the signal.

  The interference signal detectors 5e and 5f store the generated signal correction information for each channel selection in the memory 15. When selecting the same channel again, the control unit 14 can read out the phase correction information stored in the memory 15 and supply it to the phase correction units 12a and 12b to remove the interference signal. Thus, if the interference signal mixed in the receiving device is the same as the previous channel selection, the interference signal can be removed by the phase correction information stored in the memory, and the detection time of the interference signal can be reduced. Can be shortened or omitted.

  As a modification of the third embodiment, a gain correction unit (not shown) for correcting the gains of the output signal 2a ′ from the channel selection unit 2a and the output signal 2b ′ from the channel selection unit 2b may be provided. The gain correction unit of the output signal 2a ′ from the channel selection unit 2a is configured so that the interference signal included in the output signal of the subtraction unit 4a is reduced, and the gain correction unit of the output signal 2b ′ from the channel selection unit 2b is the subtraction unit. Each gain correction unit is controlled such that the interference signal included in the output signal 4b is reduced.

  As described above, in the third embodiment, the interference signal is removed by correcting the phase of the local oscillation signal output from the local oscillator 3. And even in a reception environment where interference signals are mixed in the band of the desired digital broadcast signal, this interference signal is removed and demodulation processing is performed using a high-quality digital broadcast signal to improve reception quality. Is possible.

  Further, in the third embodiment, the digital broadcast signal converted into the intermediate frequency by the channel selection units 2a and 2b is supplied to the subtraction units 4a and 4b as they are. Therefore, the digital broadcast signal output from the subtracting units 4a and 4b has little distortion and a high quality signal can be obtained.

  In FIG. 5, the interference signal removal system may be one system. That is, the subtractor 4b, the interference signal detection unit 5f, the A / D conversion unit 7c, the quadrature demodulation unit 8c, the FFT unit 9c, and the phase correction unit 12b are deleted, and the input signal of the synthesis / demodulation unit 10 is converted to the FFT units 9a and 9b. , 9d may be used as three inputs.

  FIG. 6 is a block diagram showing the configuration of the fourth embodiment (embodiment 4) of the diversity receiver according to the present invention. In the fourth embodiment, interference signal detection units 5g and 5h and signal analysis units 11a and 11b are newly provided. Elements having the same functions as those in the third embodiment (FIG. 5) are denoted by the same reference numerals.

  The signal analyzers 11a and 11b include bandpass filters that are narrower than the bandwidth of the digital broadcast signal and have a variable pass center frequency. The signal analyzers 11a and 11b cover the output signal bandwidth of the subtractors 4a and 4b, respectively. By scanning with a band pass filter, power is calculated for each narrow band section of the output signals of the subtracting units 4a and 4b.

  Interference signal detectors 5g and 5h determine that the narrow band section with the largest power is disturbed among the powers of the narrow band sections supplied from signal analyzers 11a and 11b. In addition, the interference signal detection units 5g and 5h are provided with a threshold determination circuit that determines the power of each narrowband section, and compares the power of each narrowband section supplied from the signal analysis units 11a and 11b with the threshold value. It may be determined that a narrow-band section exceeding 1 is being disturbed.

  Then, the interference signal detection units 5g and 5h supply phase correction information to the phase correction units 12a and 12b so that the power of the interference signal included in the output signals of the subtraction units 4a and 4b is reduced. The phase correction units 12a and 12b correct the phase of the local oscillation signal in accordance with the supplied phase correction information, and supply it to the channel selection units 2a and 2b. Here, the interference signal detection units 5g and 5h sequentially correct the phase correction information until the power of the interference signal included in the output signals of the subtraction units 4a and 4b becomes the minimum value, and the phase correction unit 12a repeatedly. , 12b.

  In the fourth embodiment, the interference signal detectors 5g and 5h can operate independently or in cooperation with each other. When the number of jamming signals detected in each of the jamming signal detection units 5g and 5h is one, the jamming signal detection units 5g and 5h perform control so that the power of the jamming signal detected in each jamming signal detection unit is minimized. Further, when there are a plurality of interference signals detected in each of the interference signal detection units 5g and 5h, the interference signal detection units 5g and 5h are controlled so that the total power of the plurality of interference signals detected in each interference signal detection unit is minimized. .

  Further, the interference signal detection unit 5g removes the interference signal with the highest power detected, and the interference signal detection unit 5h removes the interference signal with the highest power excluding the interference signal removed by the interference signal detection unit 5g. It can also be controlled. This makes it possible to remove two different interference signals. Further, when receiving a hierarchically transmitted digital broadcast, the interference signal detectors 5g and 5h detect an interference signal included in the band of each layer, and the interference included in the band of the layer being received. It can also be controlled to preferentially remove the signal.

  The interference signal detection units 5 g and 5 h store the generated signal correction information for each channel selection in the memory 15. When selecting the same channel again, the control unit 14 can read out the phase correction information stored in the memory 15 and supply it to the phase correction units 12a and 12b to remove the interference signal. Thus, if the interference signal mixed in the receiving device is the same as the previous channel selection, the interference signal can be removed by the phase correction information stored in the memory, and the detection time of the interference signal can be reduced. Can be shortened or omitted.

  As described above, in the fourth embodiment, the signal analyzing units 11a and 11b are provided, and the interference signals are detected and removed by analyzing the output signals of the subtracting units 4a and 4b, respectively. An effect can be obtained. Furthermore, in the fourth embodiment, the signal analysis units 11a and 11b are arranged in front of the A / D conversion units 7b and 7c. Usually, each A / D converter, each quadrature demodulator, and each FFT unit are often configured in a common LSI, and can be realized without changing the LSI when using such an LSI, which is advantageous in terms of mounting. It becomes.

  In FIG. 6, the interference signal elimination system may be one system. That is, the subtractor 4b, the interference signal detection unit 5h, the signal analysis unit 11b, the phase correction unit 12b, the A / D conversion unit 7c, the quadrature demodulation unit 8c, and the FFT unit 9c are deleted, and the input signal of the synthesis / demodulation unit 10 is removed. Three inputs from the FFT units 9a, 9b, and 9d may be used.

  In the description of each of the first to fourth embodiments, the case where the digital broadcast signal is received by the two high-frequency signal input units 1a and 1b and is selected by the two channel selection units 2a and 2b has been described. It goes without saying that each embodiment can be similarly expanded by selecting and combining two signals from among three or more input signals.

  In each of the first to fourth embodiments, the subtracters 4a and 4b are used to remove the interference signal. However, the present invention is not limited to this, and can be realized using an adder. In that case, the correction amount may be converted according to this. Further, the phase correction performed by the signal correction units 6a and 6b of the first and second embodiments and the phase correction performed by the phase correction units 12a and 12b of the third and fourth embodiments are performed by a phase shifter or This can be realized using a delay device.

  According to each of the embodiments described above, in the receiving apparatus that receives a digital broadcast signal with diversity, the signal from each antenna is subjected to arithmetic processing, and control is performed so that the interference signal included in the output signal after the arithmetic operation is reduced. As a result, it is possible to improve reception performance, and it is possible to minimize degradation of reception quality even in a reception environment in which an interference signal is mixed in a desired digital broadcast signal band.

The block diagram which shows the structure of the 1st Example of the diversity receiver by this invention. The figure which shows the mode of the disturbance signal before and after implementing the removal process of an interference signal. The figure explaining the removal method of an interference signal. The block diagram which shows the structure of the 2nd Example of the diversity receiver by this invention. The block diagram which shows the structure of the 3rd Example of the diversity receiver by this invention. The block diagram which shows the structure of the 4th Example of the diversity receiver by this invention.

Explanation of symbols

1a, 1b ... high frequency signal input section,
2a, 2b ... tuning section,
2a '... the output signal of the tuning unit 2a,
2b '... the output signal of the tuning unit 2b,
3 ... Local oscillator,
4a, 4b ... subtraction unit,
5a to 5h: interference signal detector,
6a, 6b ... signal correction unit,
7a-7d ... A / D conversion part,
8a to 8d: orthogonal demodulator,
9a to 9d ... FFT section,
10: Synthesis / demodulation unit,
11a, 11b ... signal analysis unit,
12a, 12b ... phase correction unit,
13: Decoder,
14 ... control unit,
15 ... Memory.

Claims (6)

In a diversity receiver that receives multiple systems of high-frequency signals and synthesizes diversity,
First and second channel selection sections for frequency-converting received first and second high-frequency signals into intermediate frequency signals to select first and second signals of desired channels;
A signal correction unit that performs signal correction on the first signal selected by the first channel selection unit;
A calculation unit for subtracting or adding the output signal of the signal correction unit and the second signal selected by the second channel selection unit;
An interference signal detection unit that detects an interference signal included in the output signal of the arithmetic unit and controls a correction amount of the signal correction unit;
A synthesis / demodulation unit that synthesizes and demodulates the first and second signals selected by the first and second channel selection units and the output signal of the arithmetic unit;
The diversity reception apparatus, wherein the interference signal detection unit supplies signal correction information to the signal correction unit so that the detected interference signal is reduced. In a diversity receiver that receives multiple systems of high-frequency signals and synthesizes diversity,
First and second channel selection units for frequency-converting received first and second high-frequency signals to intermediate frequency signals to select first and second signals of desired channels;
A local oscillator that supplies a local oscillation signal for frequency conversion to the first and second tuning units;
A phase correction unit that performs phase correction on a local oscillation signal supplied by the local oscillator;
An arithmetic unit for subtracting or adding the first signal selected by the first channel selection unit and the second signal selected by the second channel selection unit;
An interference signal detection unit that detects an interference signal included in the output signal of the calculation unit and controls a correction amount of the phase correction unit;
A synthesis / demodulation unit that synthesizes and demodulates the first and second signals selected by the first and second channel selection units and the output signal of the arithmetic unit;
The diversity reception apparatus, wherein the interference signal detection unit supplies phase correction information to the phase correction unit so that the detected interference signal is reduced. The diversity receiver according to claim 1, wherein
The diversity reception apparatus, wherein the interference signal detection unit supplies at least one of correction information of gain correction and phase correction as signal correction information to the signal correction unit. The diversity receiver according to claim 1 or 2,
When the received high-frequency signal is composed of a plurality of subcarrier components,
The jamming signal detector calculates the power of each subcarrier and reduces the jamming signal of the subcarrier having the largest power, or the total power of the jamming signals of each subcarrier is minimized. A diversity receiver that controls the correction unit or the phase correction unit. The diversity receiver according to claim 1 or 2,
A signal analysis unit having a bandpass filter having a narrow band and a variable pass center frequency compared to the bandwidth of a high-frequency signal to be received
The signal analysis unit calculates the power for each narrowband section of the output signal of the calculation unit by the bandpass filter,
The diversity signal detection unit controls the signal correction unit or the phase correction unit so as to reduce the interference signal in the narrow band section with the largest power based on the calculation result of the signal analysis unit. Receiver device. The diversity receiver according to claim 1 or 2,
The interference signal detection unit stores the signal correction information or the phase correction information for each channel selection time in a memory,
When the channel is selected again, the signal correction unit or the phase correction unit performs signal correction or phase correction using the signal correction information or the phase correction information signal stored in the memory. Diversity receiver.

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