JP5248397B2 - Receiver - Google Patents

Description

  The present invention relates to a receiving apparatus, and more particularly, to a receiving apparatus and a receiving method having an intermediate frequency filter band control method.

  In the terrestrial digital broadcasting field, unlike terrestrial analog broadcasting arranged every other channel, terrestrial digital broadcasting scheduled to be completely transferred from terrestrial analog broadcasting in 2011 is allowed to be arranged in continuous channels. Causes digital adjacent interference. In addition, when the transmission power difference between terrestrial analog broadcasting and terrestrial digital broadcasting is large, there is a problem that a channel that deteriorates the characteristics of digital broadcasting waves due to the influence of strong analog waves occurs. It has increased.

  FIG. 11 is a block diagram showing a configuration of a conventional receiving apparatus. In FIG. 11, the receiving device includes radio wave receiving means 11, tuning means 12, signal mixing means 13, intermediate frequency filter means 14, amplitude limit amplification means 15, detection means 16, and local oscillation frequency generation means 17. The intermediate frequency filter control means 18, the adjacent interference signal detection means 19, the modulation rate detection means 21, and the comparison determination means 20 are provided.

  The radio wave receiving means 11 described above receives the signal transmitted from the transmitting means and outputs it to the tuning means 12. The tuning unit 12 tunes to a desired frequency from the signal of the radio wave receiving unit 11 and outputs it to the signal mixing unit 13. The signal mixing unit 13 mixes signals from the tuning unit 12 and a local oscillation frequency generation unit 17 described later, and outputs the mixed signal to the intermediate frequency filter unit 14. The intermediate frequency filter unit 14 extracts the intermediate frequency from the output of the signal mixing unit 13 through a filter whose bandwidth can be changed, and outputs the intermediate frequency to the amplitude limit amplification unit 15. The intermediate frequency filter means 14 changes the bandwidth by a signal from an intermediate frequency filter control means 18 described later. The amplitude limit amplification unit 15 performs amplitude limit processing on the intermediate frequency extracted by the intermediate frequency filter unit 14 so that only frequency modulation is performed, and outputs the result to the detection unit 16. The detecting means 16 detects the frequency modulation that has been subjected to the amplitude limiting process by the amplitude limiting amplifying means 15, extracts the audio signal, and outputs it to the subsequent stage.

  The local oscillation frequency generation means 17 generates a specific frequency to extract the intermediate frequency and outputs it to the signal mixing means 13. The adjacent disturbance signal detection means 19 detects an adjacent disturbance signal from the output of the intermediate frequency filter means 14 and outputs it to the comparison determination means 20 described later. The modulation rate detection means 21 detects the modulation rate from the output of the detection means 16 and outputs it to the comparison determination means 20 described later. The comparison determination means 20 compares the magnitudes of the output signals of the adjacent interference signal detection means 19 and the modulation rate detection means 21 with the respective threshold values, and outputs a comparison determination result signal to the intermediate frequency filter control means 18 described later. The intermediate frequency filter control means 18 controls the bandwidth of the intermediate frequency filter means 14 according to the comparison determination result of the comparison determination means 20.

FIG. 12 is a flowchart for explaining the operation of the conventional adjacent interference removing means.
In FIG. 12, when the adjacent disturbance signal is detected in step S122 during the normal reception in step S121, the magnitude Vd of the adjacent disturbance signal is compared with the first threshold value Vd1 in step S123. In step S123, when the magnitude Vd of the adjacent interfering signal is larger than the predetermined first threshold value Vd1, the process proceeds to step S124. On the other hand, when the magnitude Vd of the adjacent interfering signal is smaller than the predetermined first threshold value Vd1 in step S123, the process proceeds to step S128. In step S124, the magnitude Vd of the adjacent interference signal is compared with the second threshold value Vd2. In step S124, when the magnitude Vd of the adjacent interference signal is larger than the predetermined second threshold value Vd2, the process proceeds to step S125, and the bandwidth of the intermediate frequency filter means 14 is set to the first minimum value Bw1, The process returns to step S122. On the other hand, when the magnitude Vd of the adjacent disturbance signal is smaller than the predetermined second threshold value Vd2 in step S124, the process proceeds to step S126.

  In step S126, when the magnitude Vm of the modulation signal is larger than the predetermined third threshold value Vm1, the process proceeds to step S127, the bandwidth of the intermediate frequency filter means 14 is set to the second minimum value Bw2, and the step Return to S122. On the other hand, when the magnitude Vm of the modulation signal is smaller than the predetermined third threshold value Vm1 in step S126, the process proceeds to step S125, and the bandwidth of the intermediate frequency filter means 14 is set to the first minimum value Bw1. Return to step S122.

  On the other hand, in step S128, the bandwidth of the intermediate frequency filter means 14 is compared with the maximum settable bandwidth. In step S128, when the bandwidth of the intermediate frequency filter means 14 is the same as the maximum settable bandwidth, the bandwidth of the intermediate frequency filter means 14 is maintained at the maximum settable bandwidth, and the process proceeds to step S122. Return. On the other hand, if the bandwidth of the intermediate frequency filter means 14 is different from the maximum bandwidth that can be set in step S128, the process proceeds to step S129. In step S129, comparison with the adjacent interference signal magnitude Vd and the first threshold value Vd1 is continued for a predetermined time. In step S129, when the magnitude Vd of the adjacent interfering signal is continuously smaller than the first threshold value Vd1 for a certain period of time, the process proceeds to step S130 and the bandwidth of the intermediate frequency filter means 14 is increased by one step and the process returns to step S122. . On the other hand, in step S129, when the magnitude of the adjacent disturbance signal Vd is not continuously smaller than the first threshold value Vd1 for a predetermined time, that is, when a new adjacent disturbance signal is detected, the process proceeds to step S123. Return.

  As described above, in the technique of Patent Document 1, the modulation rate of the received radio wave and the adjacent interference signal are constantly monitored, and the intermediate frequency filter is used according to the magnitudes of the output signals of the modulation rate detection means and the adjacent interference signal detection means. Since the control means can change the bandwidth of the intermediate frequency filter, a reception state with less interference and distortion can be obtained.

Japanese Patent No. 3839302 (P9, FIG. 1 and FIG. 2)

  However, since the technique of Patent Document 1 is a method of changing the intermediate frequency filter bandwidth using a predetermined threshold as a criterion, there is a case where there is an adjacent interfering wave only on one side of the sideband in the bandwidth or the reception level changes. In this case, there is a problem that the band is cut more than necessary and the reception characteristic is deteriorated.

  The reason for this is that it detects adjacent interference signals and the magnitude of the modulation rate, uses a predetermined threshold as a criterion, and uses a method of switching the intermediate frequency filter bandwidth between wide and narrow. When there is adjacent interference only above or below the occupied frequency bandwidth of the reception frequency, or when the size of the received signal fluctuates, it may be impossible to accurately detect and determine the interference wave in the frequency domain. It is done. As a result, when there is strong adjacent interference, the band is narrowed more than necessary, which causes degradation of reception characteristics. Further, when there is a moderate adjacent disturbance, the band cannot be narrowed, and there are cases where it cannot be detected at the time of a weak adjacent disturbance, and all of them leave a factor of deterioration of characteristics.

  Therefore, it is necessary to change the threshold value for detecting the adjacent interference signal according to the reception level and to remove the adjacent interference signal according to the size of the adjacent interference signal existing in the sideband.

  One aspect of the receiving apparatus according to the present invention includes a difference frequency signal generating means for outputting a difference frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency, and an intermediate by filtering the difference frequency signal. An intermediate frequency filter means for outputting a frequency; an amplitude limit amplification means for limiting the intermediate frequency to a desired amplitude using an amplitude limit amplification value; and a detection means for detecting a signal limited to the desired amplitude. , Generating a threshold variable coefficient that varies the threshold according to the amplitude limited amplification value, the size of the lower sideband and the upper sideband in the occupied frequency bandwidth of the received signal, and the threshold variable coefficient A first control signal for controlling the bandwidth of the intermediate frequency filter means and a second control for controlling the center frequency of the intermediate frequency filter means. Control signal generating means for generating a signal, intermediate frequency filter control means for adjusting the bandwidth of the intermediate frequency filter means based on the first control signal, and the intermediate frequency based on the second control signal Intermediate frequency filter shift control means for shifting the center frequency of the filter means. The magnitudes of the upper / lower sideband adjacent jamming signals are compared to detect the sideband neighboring jamming signal. As a result, it is possible to suppress degradation of reception characteristics.

An aspect of the present invention is an adjacent disturbance removing apparatus that receives a difference frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency, and outputs a signal obtained by removing the adjacent disturbance signal. Intermediate frequency filter means for filtering the differential frequency signal to output an intermediate frequency, amplitude limit amplification means for limiting the intermediate frequency to a desired amplitude using an amplitude limit amplification value, and Detection means for detecting a signal limited to a desired amplitude;
A threshold variable coefficient that varies the threshold according to the amplitude limited amplification value is generated, and the size of the lower sideband and the upper sideband in the occupied frequency bandwidth of the received signal, and the threshold variable coefficient Control signal generating means for generating a first control signal for controlling a bandwidth of the filter processing and a second control signal for controlling a center frequency of the filter processing, using a threshold value varied by using, An intermediate frequency filter control means for adjusting the bandwidth of the filter processing based on the first control signal; an intermediate frequency filter shift control means for shifting the center frequency of the filter processing based on the second control signal; Is provided.

  An aspect of the adjacent disturbance elimination method according to the present invention is to input a difference frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency, and output a signal obtained by removing the adjacent disturbance signal. The differential frequency signal is filtered to output an intermediate frequency, an amplitude limited amplification value is used to limit the intermediate frequency to a desired amplitude, and a signal limited to the desired amplitude is detected. Then, a threshold variable coefficient that varies the threshold according to the amplitude limited amplification value is generated, and the size of the lower sideband and the upper sideband in the occupied frequency bandwidth of the received signal, and the threshold variable Generating a first control signal for controlling a bandwidth of the filter process and a second control signal for controlling a center frequency of the filter process by using a threshold variable using a coefficient; signal Based on, to adjust the bandwidth of the filtering process, based on said second control signal, it shifts the central frequency of the filter.

  One aspect of the program according to the present invention is a program that realizes adjacent disturbance removal by inputting a differential frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency, and outputting a signal from which the adjacent disturbance signal is removed. An intermediate frequency filtering process for filtering the differential frequency signal and outputting an intermediate frequency; an amplitude limiting amplification process for limiting the intermediate frequency to a desired amplitude using an amplitude limiting amplification value; A detection process for detecting a signal limited to a desired amplitude, and a threshold variable coefficient for changing the threshold according to the amplitude-limited amplification value are generated, and the size of the lower sideband in the occupied frequency bandwidth of the received signal A first control signal for controlling the bandwidth of the intermediate frequency filter processing using the size of the upper sideband and a threshold variable using the threshold variable coefficient; A control signal generation process for generating a second control signal for controlling the center frequency of the intermediate frequency filter process, and an intermediate frequency filter control process for adjusting the bandwidth of the intermediate frequency filter process based on the first control signal. Based on the second control signal, the computer is caused to execute an intermediate frequency filter shift control process for shifting a center frequency of the intermediate frequency filter process.

  According to the present invention, it is possible to vary the threshold value for detecting an adjacent interference signal according to the reception level, and to remove the adjacent interference signal according to the size of the adjacent interference signal existing in the sideband.

It is a block diagram which shows the structural example of the receiver in the 1st Embodiment of this invention. It is a block diagram which shows the signal demodulation analysis means in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the adjacent disturbance removal means in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the intermediate frequency filter control process in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the signal demodulation analysis means in the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the receiver in the 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of the adjacent disturbance removal means in the 3rd Embodiment of this invention. It is a flowchart which shows the 1st intermediate | middle frequency filter control process in the 3rd Embodiment of this invention. It is a flowchart which shows the 2nd intermediate frequency filter control process in the 3rd Embodiment of this invention. It is a flowchart which shows the operation | movement of the 3rd intermediate frequency filter control process in the 3rd Embodiment of this invention. It is a block diagram which shows the structural example of the conventional receiver. It is a flowchart which shows operation | movement of the conventional adjacent disturbance removal means.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, components having the same configuration or function and corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  The present invention relates to a receiving apparatus that outputs and receives a differential frequency output between a tuning frequency and a local oscillation frequency as an intermediate frequency, and receives an occupied frequency bandwidth spectrum information generating means, an intermediate frequency filter shift control means, and a threshold variable coefficient generating means for receiving frequency. And have. The adjacent disturbance detection threshold is changed by the threshold variable coefficient output from the threshold variable coefficient generation means to increase the adjacent interference detection accuracy. Further, the bandwidth of the intermediate frequency filter means and the shift amount of the center frequency are controlled using the upper / lower adjacent interference determining means in the occupied frequency bandwidth of the reception frequency based on the spectrum information output from the spectrum information generating means. This suppresses the deterioration of reception characteristics.

  Specifically, a threshold variable coefficient that varies the threshold according to the amplitude limit amplification value used in the amplitude limit amplification process is generated, and the size of the lower sideband and the upper sideband in the occupied frequency bandwidth of the received signal are generated. The bandwidth and the center frequency of the intermediate frequency filter are controlled by using the threshold value varied by using the threshold value and the threshold variable coefficient.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the first embodiment of the receiving apparatus of the present invention. The receiving apparatus of FIG. 1 includes radio wave receiving means 31, tuning means 32, signal mixing means 33, local oscillation frequency generating means 37, and adjacent disturbance removing means (adjacent disturbance removing apparatus) 45. The adjacent interference removing unit 45 includes an intermediate frequency filter unit 34, an amplitude limit amplification unit 35, an intermediate frequency filter control unit 38, an intermediate frequency filter shift control unit 39, an adjacent interference signal detection unit 40, a comparison determination unit 41, and a threshold variable coefficient generator. Means 42 and signal demodulation analysis means 44 are provided. The signal demodulation analysis unit 44 includes a detection unit 36 and a spectrum information detection unit 43.

In FIG. 1, a difference frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency is input to the adjacent interference removing unit 45. The adjacent disturbance removing unit 45 realizes adjacent disturbance removal using each component to output a signal from which the adjacent disturbance signal is removed.
Among the components constituting the adjacent interference removing unit 45, a component included in the control signal generating unit 61 generates a threshold variable coefficient that varies the threshold according to the amplitude limit amplification value used in the amplitude limit amplification process. The bandwidth and center of the intermediate frequency filter using the lower sideband size and the upper sideband size in the occupied frequency bandwidth of the received signal, and the threshold variable using the threshold variable coefficient A function to control the frequency is realized.

  In addition, the radio wave reception unit 31, the tuning unit 32, the signal mixing unit 33, and the local oscillation frequency generation unit 37 may be referred to as a difference frequency signal generation unit. The differential frequency signal generating means realizes a function of outputting a differential frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency. Each component will be specifically described below.

The radio wave receiving unit 31 receives a signal transmitted from a transmitting unit (not shown) and outputs the signal to the tuning unit 32.
The tuning unit 32 tunes the signal output from the radio wave receiving unit 31 to a desired frequency and outputs the signal to the signal mixing unit 33.
The signal mixing unit 33 mixes signals from the tuning unit 32 and a local oscillation frequency generation unit 37 described later, and outputs a differential frequency output between the tuning frequency obtained by the tuning unit 32 and the local oscillation frequency to the intermediate frequency filter unit 34. To do.

The intermediate frequency filter unit 34 extracts the intermediate frequency from the output of the signal mixing unit 33 through a filter whose bandwidth and center frequency can be changed, and outputs the intermediate frequency to the amplitude limit amplification unit 35.
The intermediate frequency filter means 34 changes the bandwidth according to a signal from an intermediate frequency filter control means 38 described later. Further, the center frequency of the intermediate frequency filter is shifted in accordance with a signal from an intermediate frequency filter shift control means 39 described later.

  The amplitude limit amplification means 35 performs amplitude limit amplification processing on the intermediate frequency extracted by the intermediate frequency filter means 34 and outputs the result to the detection means 36. Specifically, the desired amplitude is increased when the intermediate frequency is small, and is decreased when the amplitude is large.

  The detection means 36 detects the frequency modulation subjected to the amplitude limit amplification process by the amplitude limit amplification means 35, extracts the signal, and outputs it to the subsequent stage.

  The local oscillation frequency generation unit 37 generates a specific frequency to extract the intermediate frequency and outputs it to the signal mixing unit 33.

  The adjacent disturbance signal detection means 40 detects an adjacent disturbance signal from the output of the intermediate frequency filter means 34 and outputs it to the comparison determination means 41 described later.

  The threshold variable coefficient generation means 42 generates a threshold variable coefficient from the amplitude limit amplification signal determined by the amplitude limit amplification means 35 and outputs the threshold variable coefficient to the comparison determination means 41. The threshold variable coefficient generating unit 42 determines the threshold variable coefficient as an input, an amplitude limit amplification value for performing amplitude limitation on the intermediate frequency input from the intermediate frequency filter unit 34 by the amplitude limit amplification unit 35. Specifically, when the amplitude amplification value is small (when it is smaller than the desired amplitude), the threshold variable coefficient generation unit 42 uses the threshold values Vd1, Vd2, Vsd1, Vsu1, Vsd2, Vsu2 as the threshold variable coefficients. Set the coefficient to decrease. When the amplitude amplification value is large, the reverse is set. Specifically, when the amplitude amplification value when the signal of the intermediate frequency has a desired amplitude is set as a reference value, when the amplitude amplification value is smaller than the reference value, each threshold value is reduced as a threshold variable coefficient. When the amplitude amplification value is larger than the reference value, the threshold value variable coefficient is set so that each threshold value becomes larger.

  When the threshold variable coefficient generating means 42 sets the threshold variable coefficient, the following effects can be obtained. For example, when the size of the received signal is small and the desired wave and the adjacent interfering wave are small, amplitude limiting amplification processing is performed on the received signal. The threshold variable coefficient generation unit 42 generates a threshold variable coefficient based on the amplitude limit amplification value of the amplitude limit amplification unit 35. Since the threshold can be adaptively changed using the threshold variable coefficient, the comparison / determination unit 41 can detect the adjacent interfering wave using the threshold corresponding to the magnitude of the received signal.

  The spectrum information detection unit 43 generates spectrum information for the intermediate frequency that has been subjected to the amplitude limit amplification process by the amplitude limit amplification unit 35, and the size of the upper sideband of the occupied frequency bandwidth of the reception frequency, the upper side The size of the sideband is detected and output to the comparison / determination means 41.

  The comparison determination unit 41 compares the result of comparison between the magnitude of the output signal of the adjacent interference signal detection unit 40 and the threshold value determined by the output signal of the threshold variable coefficient generation unit 42, and the output signal of the spectrum information detection unit 43. A control signal generated based on the comparison result of the magnitude and the threshold value is output to an intermediate frequency filter control means 38 and an intermediate frequency filter shift control means 39 described later.

  Specifically, the comparison determination unit 41 outputs a first control signal for adjusting the bandwidth of the intermediate frequency filter unit 34 to the intermediate frequency filter control unit 38. The second control signal for shifting the center frequency of the intermediate frequency filter means 34 is output to the intermediate frequency filter shift control means 39. The first control signal instructs the control to change the bandwidth of the intermediate frequency filter to a preset value or to widen the current bandwidth by one step. In addition, the second control signal instructs control to return the intermediate frequency to the center, to shift the intermediate frequency downward by one step, or to shift upward by one step.

  For example, when the intermediate frequency lower shift amount of the filter of the intermediate frequency filter unit 34 is set to a one-stage lower shift, the comparison determination unit 41 shifts the intermediate frequency lower shift amount of the filter by one lower step. Two control signals are generated and notified to the intermediate frequency filter shift control means 39. The intermediate frequency filter shift control means 39 shifts the center frequency of the intermediate frequency filter means 34 based on the second control signal.

  The intermediate frequency filter control unit 38 controls the bandwidth of the intermediate frequency filter unit 34 according to the comparison determination result (first control signal) of the comparison determination unit 41.

  The intermediate frequency filter shift control means 39 is configured to shift control the center frequency of the intermediate frequency filter band of the intermediate frequency filter means 34 according to the comparison determination result (second control signal) of the comparison determination means 41.

  FIG. 2 is a block diagram showing signal demodulation analysis means in the first embodiment of the present invention. The spectrum information detection means 43 in FIG. 2 includes an analog / digital conversion means 46 and a Fourier transform means 47.

The analog-to-digital conversion unit 46 performs analog-to-digital conversion on the output of the intermediate frequency of the amplitude limiting amplification unit 35 described above and outputs it to the Fourier transform unit 47.
The Fourier transform means 47 is the magnitude of the adjacent disturbance signal in the upper sideband of the spectrum information obtained by Fourier transforming the signal of the analog-digital conversion means 46, and the magnitude of the adjacent disturbance signal in the lower sideband of the spectrum information. Is detected and output to the subsequent stage.

FIG. 3 is a flowchart showing the operation of the adjacent disturbance removing unit according to the first embodiment of the present invention. The operation of FIG. 1 will be described with reference to FIG.
In FIG. 3, during normal reception (step S20), in step S21, the adjacent interference signal detection means 40 detects the adjacent interference signal, and the spectrum information detection means 43 detects the spectrum information.

In step S22, the comparison determination unit 41 uses the threshold variable coefficient output from the threshold variable coefficient generation unit 42 to change the predetermined threshold Vd1 by the threshold variable coefficient, and the predetermined threshold. A threshold value Vd2α obtained by varying Vd2 by a threshold variable coefficient is set. Specifically, the threshold Vd1α is calculated by multiplying the threshold Vd1 and the threshold variable coefficient, and the threshold Vd2α is calculated by multiplying the threshold Vd2 and the threshold variable coefficient. Here, it is assumed that the threshold value Vd1α is smaller than the threshold value Vd2α.
The threshold variable coefficient is determined by the threshold variable coefficient generating unit 42 according to the amplitude limit amplification value input from the amplitude limit amplification unit 35. The amplitude limit amplification value is a value for the amplitude limit amplification unit 35 to limit the amplitude of the intermediate frequency input from the intermediate frequency filter unit 34.

  In step S23, the comparison / determination unit 41 compares the magnitude Vd of the adjacent disturbance signal with the threshold value Vd1α. If the magnitude Vd of the adjacent disturbance signal is larger than the threshold value Vd1α, the process proceeds to step S24, and the magnitude of the adjacent disturbance signal. When Vd is smaller than the threshold value Vd1α, the process proceeds to step S46.

  In step S24, the comparison / determination means 41 compares the adjacent disturbing signal magnitude Vd with the threshold value Vd2α, and if the adjacent disturbing signal magnitude Vd is larger than the threshold value Vd2α, the process proceeds to step S202, where the adjacent disturbing signal magnitude. When Vd is smaller than the threshold value Vd2α, the process proceeds to step S200.

  In step S200, the comparison determination unit 41 sets the second minimum value Bw2 in BwX1 of the intermediate frequency filter bandwidth used in the intermediate frequency filter control processing in step S201, and sets the third minimum value Bw3 in BwX2. The process proceeds to step S201.

  In step S202, the comparison determination unit 41 sets the first minimum value Bw1 to BwX1 of the intermediate frequency filter bandwidth used in the intermediate frequency filter control process of step S201, and sets the second minimum value Bw2 to BwX2. The process proceeds to step S201.

  In step S201, the intermediate frequency filter control means 38 performs an intermediate frequency filter process, and returns to step S21 after the process is completed. The value of the minimum value described above has a relationship of first minimum value Bw1 <second minimum value Bw2 <third minimum value Bw3.

In step S46, the comparison / determination unit 41 compares the bandwidth of the intermediate frequency filter unit 34 with the maximum settable bandwidth.
Based on the comparison result, when the bandwidth of the intermediate frequency filter means 34 is the same as the maximum settable bandwidth, the bandwidth of the intermediate frequency filter means 34 is maintained at the maximum settable bandwidth, Proceed to S52. When the bandwidth of the intermediate frequency filter means 34 is different from the maximum bandwidth that can be set, the process proceeds to step S47.

  In step S47, the comparison / determination means 41 determines the magnitude Vd and threshold value Vd1α of the adjacent disturbance signal for a certain period of time, the magnitude Vsu and threshold value Vsu1 of the upper sideband of the spectrum information, and the magnitude of the lower sideband of the spectrum information. The comparison between Vsd and threshold value Vsd1 is continued.

  In step S47, the comparison / determination means 41 determines that the magnitude Vd of the adjacent interfering signal is not continuously smaller than the threshold value Vd1α for a predetermined time, and the magnitude Vsu of the upper sideband of the spectrum information is continued from the threshold value Vsu1. If it is not smaller and the size Vsd of the lower sideband of the spectrum information is not continuously smaller than the threshold value Vsd1, that is, if a new adjacent interference signal is detected, the process returns to step S22. On the other hand, the comparison / determination means 41 has the magnitude Vd of the adjacent interfering signal continuously smaller than the threshold value Vd1α for a certain time, the magnitude Vsu of the upper sideband of the spectrum information is continuously smaller than the threshold value Vsu1, and the spectrum information When the lower sideband size Vsd is continuously smaller than the threshold value Vsd1, the process proceeds to step S48.

  In step S48, the intermediate frequency filter control means 38 increases the bandwidth of the intermediate frequency filter means 34 by one step and proceeds to step S49.

In step S49, the comparison determination unit 41 determines whether both the intermediate frequency upper shift amount and the intermediate frequency lower shift amount of the filter of the intermediate frequency filter unit 34 are 0 values, that is, there is no shift.
When the intermediate frequency of the filter of the intermediate frequency filter means 34 is neither shifted upward nor shifted downward, the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is 0, and the intermediate frequency lower shift amount of the filter is 0. And the process returns to step S21.
When either or both of the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 and the lower intermediate frequency shift amount of the filter are different from the zero value, the process proceeds to step S50.

In step S50, the comparison / determination means 41 compares the magnitude Vd and the threshold value Vd1α of the adjacent interfering signal for a predetermined time, compares the magnitude Vsu of the upper sideband of the spectrum information with the threshold value Vsu1, and lowers the spectrum information. The waveband size Vsd and the threshold value Vsd1 are continuously compared.
The magnitude Vd of the adjacent disturbance signal for a certain period of time is not continuously smaller than the threshold value Vd1α, the magnitude Vsu of the upper sideband of the spectrum information is not continuously smaller than the threshold value Vsu1, and When the side sideband size Vsd is not continuously smaller than the threshold value Vsd1, that is, when a new adjacent disturbance signal is detected, the process returns to step S22.
The magnitude Vd of the adjacent interfering signal is continuously smaller than the threshold value Vd1α for a fixed time, the magnitude Vsu of the upper sideband of the spectrum information is continuously smaller than the threshold value Vsu1, and the magnitude of the lower sideband of the spectrum information When the value Vsd is continuously smaller than the threshold value Vsd1, the process proceeds to step S51.

  In step S51, the intermediate frequency filter shift control means 39 shifts the intermediate frequency to the center of the first stage and returns to step S21.

In step S52, the comparison determination unit 41 determines whether both the intermediate frequency upper shift amount and the intermediate frequency lower shift amount of the filter of the intermediate frequency filter unit 34 are 0 values, that is, there is no shift.
When the intermediate frequency of the filter of the intermediate frequency filter means 34 is neither shifted upward nor shifted downward, the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is 0, and the intermediate frequency lower shift amount of the filter is 0. And the process returns to step S21.
When either or both of the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 and the lower intermediate frequency shift amount of the filter are different from the zero value, the process proceeds to step S53.

  In step S53, the comparison / determination means 41 compares the adjacent interference signal magnitude Vd and the threshold value Vd1α for a predetermined time, compares the spectrum information upper sideband magnitude Vsu with the threshold value Vsu1, and the spectrum information. The lower sideband size Vsd is continuously compared with the threshold value Vsd1.

The magnitude Vd of the adjacent interfering signal is not continuously smaller than the threshold value Vd1α for a predetermined time, or the upper sideband magnitude Vsu of the predetermined time spectrum information is longer than the threshold value Vsu1. Is not small or when the size Vsd of the lower sideband of the spectrum information determined in advance for a predetermined time is not continuously smaller than the threshold value Vsd1, that is, adjacent interference is newly detected by the spectrum information. If so, the process returns to step S22.
The magnitude Vd of the adjacent interfering signal for a certain period of time is continuously smaller than the threshold value Vd1α, the magnitude Vsu of the upper sideband of the spectrum information is continuously smaller than the threshold value Vsu1, and the magnitude of the lower sideband of the spectrum information When the magnitude Vsd is continuously smaller than the threshold value Vsd1, the process proceeds to step S54.

  In step S54, the intermediate frequency filter shift control means 39 shifts the intermediate frequency to the center of the first stage and returns to step S21.

  FIG. 4 is a flowchart showing the operation of the intermediate frequency filter control process in the first embodiment of the present invention.

In step S25, the comparison / determination means 41 compares the size Vsu of the upper sideband of the spectrum information with the threshold value Vsu1.
When the magnitude Vsu of the upper sideband of the spectrum information is larger than the threshold value Vsu1, the process proceeds to step S26, and when the magnitude Vsu of the upper sideband of the spectrum information is smaller than the threshold value Vsu1, the process proceeds to step S30.

In step S26, the comparison determination means 41 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd1.
When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd1, the process proceeds to step S34, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd1, the process proceeds to step S27.

In step S27, the comparison determination unit 41 compares the lower shift amount of the intermediate frequency of the filter of the intermediate frequency filter unit 34 with the maximum value of the settable lower shift amount.
When the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is maximum, the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is maintained at the maximum value, and the process proceeds to step S34.
When the intermediate frequency lower shift amount of the intermediate frequency filter means 34 is different from the maximum, the process proceeds to step S28.

In step S28, the comparison determination unit 41 compares the size Vsd-1 of the lower sideband of the previous spectrum information with the threshold value Vsd1.
When the size Vsd-1 of the lower sideband of the previous spectrum information is larger than the threshold value Vsd1, the process proceeds to step S34, and the size Vsd-1 of the lower sideband of the previous spectrum information is set. When it is smaller than the threshold value Vsd1, the process proceeds to step S29.

  In step S29, the intermediate frequency filter shift control means 39 sets the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 to a one-stage lower shift, and ends the intermediate frequency filter control process.

In step S30, the comparison determination means 41 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd1.
When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd1, the process proceeds to step S31, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd1, the process proceeds to step S35.

In step S31, the comparison determination unit 41 compares the upper shift amount of the intermediate frequency of the filter of the intermediate frequency filter unit 34 with the maximum value of the settable upper shift amount.
When the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is the maximum, the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is maintained at the maximum value, and the process proceeds to step S34, and the intermediate frequency filter means 34 is reached. When the intermediate frequency upper side shift amount of the filter is different from the maximum, the process proceeds to step S32.

In step S32, the comparison / determination means 41 compares the size Vsu-1 of the upper sideband of the previous spectrum information with the threshold value Vsu1.
When the size Vsu-1 of the upper sideband of the previous spectrum information is larger than the threshold value Vsu1, the process proceeds to step S34, and the size Vsu-1 of the upper sideband of the previous spectrum information is the threshold value Vsu1. If smaller, the process proceeds to step S33.

  In step S33, the intermediate frequency filter shift control means 39 sets the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 to the one-stage upper shift, and ends the intermediate frequency filter control process.

  In step S34, the intermediate frequency filter control unit 38 sets the bandwidth of the intermediate frequency filter unit 34 to the minimum value BwX1, and ends the intermediate frequency filter control process.

  In step S35, the intermediate frequency filter control unit 38 sets the bandwidth of the intermediate frequency filter unit 34 to the minimum value BwX2, and ends the intermediate frequency filter control process.

  In the first embodiment of the present invention, in a receiving device that outputs a differential frequency output between a tuning frequency and a local oscillation frequency by receiving an intermediate frequency, spectrum information of an occupied frequency bandwidth of the reception frequency is generated to generate an upper / lower side wave. Spectrum information detecting means for detecting a band adjacent interference signal and threshold variable coefficient generating means. The magnitude of the adjacent disturbance detection signal is detected by comparing with the threshold value and constantly monitored, and the magnitude of the upper / lower sideband adjacent disturbance signal is constantly monitored. As a threshold for judging the magnitude of the adjacent jamming signal, at this time, as a reference threshold for controlling the center frequency shift of the filter and the bandwidth of the filter, the judgment threshold for the neighboring jamming signal that can be changed by the threshold variable coefficient generating means And use. Also, the threshold is used to determine the magnitude of the upper / lower sideband adjacent disturbance signal based on the spectrum information, and the magnitudes of the lower and upper sideband adjacent disturbance signals are compared. Detect adjacent jamming signals. Thereby, it is possible to suppress the deterioration of the reception characteristics.

Specifically, since the magnitude of the received signal varies depending on the state of the transmission path, the threshold variable coefficient generating unit 42 performs amplitude limit amplification processing on the received signal, and amplitude limit amplification used by the amplitude limit amplification unit 35. A threshold variable coefficient is generated according to the value.
For example, a case where the received signal is small and the desired wave and the adjacent interfering wave are small will be described. When the magnitude of the received signal is small and both the desired wave and the adjacent interference wave are small, the threshold variable coefficient generating means 42 generates a threshold variable coefficient that reduces the threshold for determining the adjacent interference signal according to the amplitude limit amplification value. . As described above, since the threshold value can be adaptively changed using the threshold variable coefficient corresponding to the amplitude limit amplification value, it is possible to detect the adjacent interfering wave with the threshold value corresponding to the magnitude of the received signal. .

  Next, when the size of the received signal is medium and the adjacent sideband adjacent interference wave is larger than the desired wave size, the upper / lower sidebands detected by the spectrum information detecting means 43 Is used to determine which of the upper / lower sidebands has the adjacent jamming signal. This makes it possible to detect adjacent interference signals present in the upper / lower sidebands.

(Second Embodiment)
FIG. 5 is a block diagram showing a configuration example of signal demodulation analysis means different from FIG. The spectrum information detection means 43 in FIG. 5 includes an analog / digital conversion means 46, a Fourier transform means 47, and an orthogonal demodulation means 48.

The analog-to-digital conversion means 46 performs analog-to-digital conversion on the output of the intermediate frequency of the amplitude limiting amplification means 35 described above and outputs the result to the orthogonal demodulation means 48.
The orthogonal demodulation unit 48 performs orthogonal demodulation of the OFDM signal and outputs the result to the Fourier transform unit 47.
The Fourier transform means 47 detects the magnitude of the upper sideband of the spectrum information obtained by Fourier transforming the orthogonal demodulated signal and the magnitude of the lower sideband of the spectrum information and outputs it to the subsequent stage.

  In the second embodiment, orthogonal demodulation of an OFDM (Orthogonal Frequency Division Multiplexing) signal is performed, and the size of the upper sideband or lower sideband of the spectrum information is detected by the Fourier transform means 47 to detect the upper sideband. The band or the lower sideband adjacent interference wave can be determined. Therefore, the present invention can be applied to a receiving apparatus to which OFDM is applied.

(Third embodiment)
FIG. 6 is a block diagram showing a third embodiment of the receiving apparatus of the present invention. The spectrum information detection means 50 in FIG. 6 generates spectrum information from the output of the intermediate frequency filter means 34, and determines the size of the adjacent disturbance signal in the lower sideband of the occupied frequency bandwidth of the reception frequency and the upper sideband. The magnitude of the adjacent interference signal is detected and output to the comparison determination means 51 described later. The threshold variable coefficient generation means 42 generates a threshold variable coefficient from the amplitude limit amplification signal determined by the amplitude limit amplification means 35 and outputs the threshold variable coefficient to the comparison determination means 51. The comparison determination means 51 outputs a control signal generated from the comparison determination result between the magnitude of the output signal of the spectrum information detection means 50 and the threshold determined by the output signal of the threshold variable coefficient generation means 42 to the intermediate frequency filter control means 38. The output is to the intermediate frequency filter shift control means 39.

  In FIG. 6, the threshold variable that varies the threshold according to the amplitude limit amplification value used in the amplitude limit amplification process by the component included in the control signal generation unit 62 among the components configuring the adjacent disturbance removing unit 52. A coefficient is generated, and the size of the adjacent side interference signal in the lower sideband and the size of the adjacent sideband interference signal in the upper sideband in the occupied frequency bandwidth of the received signal, and the threshold value variable using the threshold variable coefficient are set. Used to realize the function of controlling the bandwidth and center frequency of the intermediate frequency filter.

As in the first embodiment, the comparison determination unit 51 outputs a first control signal for adjusting the bandwidth of the intermediate frequency filter unit 34 to the intermediate frequency filter control unit 38. The second control signal for shifting the center frequency of the intermediate frequency filter means 34 is output to the intermediate frequency filter shift control means 39.
In FIG. 6, the same reference numerals as those in FIG.

  FIG. 7 is a flowchart showing the operation of the adjacent disturbance removing unit according to the third embodiment of the present invention. The operation of FIG. 6 will be described with reference to FIG.

  In FIG. 7, in step S60, during normal reception, the spectrum information detecting means 50 detects spectrum information in step S61.

  In step S62, the comparison determination unit 51 changes a plurality of predetermined thresholds using the threshold variable coefficient output from the threshold variable coefficient generation unit 42. Specifically, the comparison determination unit 51 includes a threshold Vsu1α obtained by changing a predetermined threshold Vsu1 by a threshold variable coefficient, a threshold Vsd1α obtained by changing a predetermined threshold Vsd1 by a threshold variable coefficient, and a predetermined threshold. A threshold value Vsu2α in which Vsu2 is varied by a threshold variable coefficient and a threshold value Vsd2α in which a predetermined threshold Vsd2 is varied by a threshold variable coefficient are set. The threshold variable coefficient is determined by the threshold variable coefficient generating unit 42 according to the amplitude limit amplification value input from the amplitude limit amplification unit 35 with respect to the intermediate frequency input from the intermediate frequency filter unit 34. Here, it is assumed that the threshold value Vsu1α is smaller than the threshold value Vsu2α. Further, it is assumed that the threshold value Vsd1α is smaller than the threshold value Vsd2α.

  In step S63, the comparison / determination means 51 compares the magnitude Vsu of the upper sideband of the spectrum information with the threshold value Vsu1α. If the magnitude Vsu of the upper sideband of the spectrum information is larger than the threshold value Vsu1α, the process proceeds to step S64. If the magnitude Vsu of the upper sideband of the spectrum information is smaller than the threshold value Vsu1α, the process proceeds to step S86.

  In step S64, the comparison determination unit 51 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd1α. When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd1α, the process proceeds to step S251, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd1α, the process proceeds to step S250.

In step S250, a first intermediate frequency filter process is performed, and the process returns to step S61 after the process ends.
In step S251, the second intermediate frequency filter process is performed, and after the process is completed, the process returns to step S61.

  In step S86, the comparison determination means 51 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd1α. When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd1α, the process proceeds to step S253, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd1α, the process proceeds to step S96.

  In step S253, a third intermediate frequency filter process is performed, and the process returns to step S61 after the process ends.

  In step S96, the comparison / determination means 51 compares the bandwidth of the intermediate frequency filter means 34 and the maximum settable bandwidth. When the bandwidth of the intermediate frequency filter means 34 is the same as the maximum value of the settable bandwidth, the bandwidth of the intermediate frequency filter means 34 is maintained at the maximum value of the settable bandwidth, and the process proceeds to step S99, where the intermediate frequency When the bandwidth of the filter means 34 is different from the maximum bandwidth that can be set, the process proceeds to step S97.

  In step S97, the comparison / determination means 51 determines the upper sideband size Vsu and threshold value Vsu1α of the predetermined constant time spectrum information and the lower sideband size of the predetermined constant time spectrum information. Vsd is compared with the threshold value Vsd1α, and the following processing is performed. The size Vsu of the upper sideband of the predetermined fixed time spectrum information is not continuously smaller than the threshold value Vsu1α, and the size Vsd of the lower sideband of the predetermined fixed time spectrum information is the threshold value Vsd1α. If the adjacent disturbance is newly detected from the spectrum information, the process returns to step S62. Continue to compare the upper sideband size Vsu of the spectrum information for a predetermined time with the threshold value Vsu1α, and compare the lower sideband size Vsd of the spectrum information with the threshold value Vsd1α. When the sideband size Vsu is continuously smaller than the threshold value Vsu1α, and the lower sideband size Vsd of the spectrum information is continuously smaller than the threshold value Vsd1α, the process proceeds to step S98.

  In step 98, the bandwidth of the intermediate frequency filter means 34 is increased by one step and the process returns to step S61.

  In step S99, the comparison / determination means 51 compares that the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is 0 and the intermediate frequency lower shift amount of the filter is 0. When the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is 0 and the intermediate frequency lower shift amount of the filter is 0, the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is 0 and the intermediate frequency of the filter The lower shift amount is maintained at 0, and the process returns to step S61. When the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is different from 0, or when the intermediate frequency lower shift amount of the filter is different from 0, the process proceeds to step S100.

  In step S100, the comparison / determination means 51 determines the upper sideband size Vsu and threshold Vsu1α of the predetermined constant time spectrum information and the lower sideband size of the predetermined fixed time spectrum information. Vsd and threshold value Vsd1α are compared, and the following processing is performed. Specifically, the size Vsu of the upper sideband of the predetermined constant time spectrum information is not continuously smaller than the threshold value Vsu1α, and the size of the lower sideband of the predetermined time spectrum information is predetermined. When Vsd is not continuously smaller than the threshold value Vsd1α, that is, when adjacent interference is newly detected by spectrum information, the process returns to step S62. Continue to compare the upper sideband size Vsu of the spectrum information for a predetermined time with the threshold value Vsu1α, and compare the lower sideband size Vsd of the spectrum information with the threshold value Vsd1α. When the sideband size Vsu is continuously smaller than the threshold value Vsu1α and the lower sideband size Vsd of the spectrum information is continuously smaller than the threshold value Vsd1α, the process proceeds to step S101.

  In step S101, the intermediate frequency is shifted to the center of the first stage, and the process returns to step S61.

  FIG. 8 is a flowchart showing a first intermediate frequency filter control process in the third embodiment of the present invention.

  In step S66, the comparison determination means 51 compares whether the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is the maximum. When the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is the same as the maximum value, the maximum value of the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is maintained, and the process proceeds to step S65. When the intermediate frequency lower shift amount of the intermediate frequency filter means 34 is different from the maximum value, the process proceeds to step S67.

  In step S67, the comparison determination unit 51 compares the size Vsd-1 of the lower sideband of the previous spectrum information with the threshold value Vsd1α. When the size Vsd-1 of the lower sideband of the previous spectrum information is larger than the threshold value Vsd1α, the process proceeds to step S65, and the size Vsd-1 of the lower sideband of the previous spectrum information is set. When it is smaller than the threshold value Vsd1α, the process proceeds to step S68.

  In step S68, the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is set to one step lower shift, and the first intermediate frequency filter control process is terminated.

  In step S65, the comparison / determination means 51 compares the size Vsu of the upper sideband of the spectrum information with the threshold value Vsu2α. When the size Vsu of the upper sideband of the spectrum information is larger than the threshold value Vsu2α, the process proceeds to step S73, and when the size Vsu of the upper sideband of the spectrum information is smaller than the threshold value Vsu2α, the process proceeds to step S69.

In step S69, the bandwidth of the intermediate frequency filter means 34 is set to the second minimum value Bw2, and the first intermediate frequency filter control process is terminated.
A step S73 sets the bandwidth of the intermediate frequency filter means 34 to the first minimum value Bw1, and ends the first intermediate frequency filter control process. Here, the above-described minimum value has a relationship of first minimum value Bw1 <second minimum value Bw2.

  FIG. 9 is a flowchart showing a second intermediate frequency filter control process in the third embodiment of the present invention.

  In step S74, the comparison determination means 51 compares the magnitude Vsu of the upper sideband of the spectrum information with the threshold value Vsu2α. When the size Vsu of the upper sideband of the spectrum information is larger than the threshold value Vsu2α, the process proceeds to step S75, and when the size Vsu of the upper sideband of the spectrum information is smaller than the threshold value Vsu2α, the process proceeds to step S80.

  In step S75, the comparison determination means 51 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd2α. When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd2α, the process proceeds to step S79, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd2α, the process proceeds to step S76.

  In step S76, the comparison determination means 51 compares whether the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is maximum. When the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is the same as the maximum value, the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is maintained at the maximum value, and the process proceeds to step S79. When the intermediate frequency lower shift amount of the intermediate frequency filter means 34 is different from the maximum value, the process proceeds to step S77.

  In step S77, the comparison determination unit 51 compares the size Vsd-1 of the lower sideband of the previous spectrum information with the threshold value Vsd2α. When the size Vsd-1 of the lower sideband of the previous spectrum information is larger than the threshold value Vsd2α, the process proceeds to step S79, and the size Vsd-1 of the lower sideband of the previous spectrum information is set. When it is smaller than the threshold value Vsd2α, the process proceeds to step S78.

  In step S78, the intermediate frequency lower shift amount of the filter of the intermediate frequency filter means 34 is set to one step lower shift, and the second intermediate frequency filter control process ends.

  In step S79, the bandwidth of the intermediate frequency filter means 34 is set to the first minimum value Bw1, and the second intermediate frequency filter control process is terminated.

  In step S80, the comparison determination unit 51 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd2α. When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd2α, the process proceeds to step S81, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd2α, the process proceeds to step S85.

  In step S81, the comparison determination means 51 compares whether the intermediate frequency upper shift amount of the intermediate frequency filter means 34 filter is the maximum value. When the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is the same as the maximum value, the maximum value of the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is maintained, and the process proceeds to step S79 and the intermediate frequency filter means When the intermediate frequency upper shift amount of the 34 filter is different from the maximum value, the process proceeds to step S82.

  In step S82, the comparison determination unit 51 compares the size Vsu-1 of the upper sideband of the previous spectrum information with the threshold value Vsu2α. When the size Vsu-1 of the upper sideband of the previous spectrum information is larger than the threshold value Vsu2α, the process proceeds to step S79, and the size Vsu-1 of the upper sideband of the previous spectrum information is the threshold value Vsu2α. If it is smaller, the process proceeds to step S83.

In step S83, the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is set to one-stage upper shift, and the second intermediate frequency filter control process is terminated.
In step S85, the bandwidth of the intermediate frequency filter means 34 is set to the second minimum value Bw2, and the second intermediate frequency filter control process is terminated.

  FIG. 10 is a flowchart showing the operation of the third intermediate frequency filter control process in the third embodiment of the present invention.

  In step S88, the comparison determination unit 51 compares the intermediate frequency upper shift amount of the filter of the intermediate frequency filter unit 34 with the maximum value. When the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is the same as the maximum value, the maximum value of the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is maintained, and the process proceeds to step S87, where the intermediate frequency filter means When the intermediate frequency upper shift amount of the 34 filter is different from the maximum value, the process proceeds to step S89.

  In step S89, the size Vsu-1 of the upper sideband of the spectrum information in which the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is the previous maximum value is compared with the threshold value Vsu1α. When the size Vsu-1 of the upper sideband of the previous spectrum information is larger than the threshold value Vsu1α, the process proceeds to step S87, and the size Vsu-1 of the upper sideband of the previous spectrum information is the threshold value Vsu1α. If it is smaller, the process proceeds to step S90.

  In step S90, the intermediate frequency upper shift amount of the filter of the intermediate frequency filter means 34 is set to a one-stage upper shift, and the third intermediate frequency filter control process ends.

  In step S87, the comparison determination unit 51 compares the size Vsd of the lower sideband of the spectrum information with the threshold value Vsd2α. When the size Vsd of the lower sideband of the spectrum information is larger than the threshold value Vsd2α, the process proceeds to step S95, and when the size Vsd of the lower sideband of the spectrum information is smaller than the threshold value Vsd2α, the process proceeds to step S91.

  In step S91, the bandwidth of the intermediate frequency filter means 34 is set to the second minimum value Bw2, and the third intermediate frequency filter control process is terminated.

  In step S95, the bandwidth of the intermediate frequency filter means 34 is set to the first minimum value Bw1, and the third intermediate frequency filter control process is terminated.

  In the third embodiment, it is possible to detect the spectrum information of the adjacent interfering wave in front of the amplitude limiting amplification means as compared with the first embodiment. Specifically, first, the spectrum information detecting means 50 constantly monitors spectrum information including the adjacent disturbance signal before amplitude limitation of the received radio wave. Thereby, the magnitude of the adjacent disturbance signal in the lower / upper sideband can be detected. Further, the comparison determination unit 51 varies a plurality of thresholds for detecting the adjacent disturbance signal using the threshold variable coefficient generated by the threshold variable coefficient generation unit 42. The plurality of variable threshold values are compared with the magnitudes of adjacent interference signals in the lower / upper sidebands detected by the spectrum information detecting means 50. Based on the comparison result, the intermediate frequency filter control means 38 changes the bandwidth of the intermediate frequency filter means 34, and the intermediate frequency filter shift control means 39 shifts the center frequency of the band of the intermediate frequency filter means 34, thereby receiving Deterioration of characteristics can be suppressed.

(Other embodiments)
The adjacent disturbance removing means described in the above embodiments can be realized by software, hardware, or a combination thereof. Further, when the adjacent disturbance removing unit is realized using a program, an apparatus (computer) that realizes the adjacent disturbance removing unit includes a CPU (Central Processing Unit) and a memory. The program is loaded into a memory in the computer and executes a group of instructions included in the program under the control of the CPU. A program for causing a computer to realize the adjacent disturbance removing unit includes at least a group of instructions for realizing the following processing.

(1) Intermediate frequency filter processing for filtering the difference frequency signal and outputting an intermediate frequency. (2) Amplitude limiting amplification processing for limiting the intermediate frequency to a desired amplitude using the amplitude limiting amplification value. (3) Detection processing for detecting a signal limited to a desired amplitude. (4) A threshold variable coefficient that varies the threshold according to the amplitude limit amplification value is generated, and the magnitude of the adjacent disturbance signal in the lower sideband and the adjacent disturbance signal in the upper sideband in the occupied frequency bandwidth of the received signal A first control signal for controlling the bandwidth of the intermediate frequency filtering process using a magnitude and a threshold variable using a threshold variable coefficient, and a second control signal for controlling the center frequency of the intermediate frequency filtering process And control signal generation processing to generate. (5) An intermediate frequency filter control process for adjusting the bandwidth of the intermediate frequency filter process based on the first control signal. (6) Intermediate frequency filter shift control processing for shifting the center frequency of the intermediate frequency filter processing based on the second control signal.
The program can be recorded on a computer-readable recording medium.

According to each said embodiment, there can exist the following effects. As a first effect, it is possible to suppress degradation of reception characteristics such as interference and distortion of received signals. The reason is that by using the adjacent interference judgment means of the upper / lower sidebands from the spectrum information in the occupied frequency bandwidth of the reception frequency and the technology for shifting the center frequency of the intermediate frequency filter, the band is more than necessary. It is because it does not cut.
As a second effect, adjacent interference determination can be performed without being affected by the received signal level. The reason is that the adjacent interference determination threshold value is adaptively controlled according to the received signal level by the threshold variable coefficient from the threshold variable coefficient generating means 42.

  In addition, this invention is not limited to embodiment shown above. Within the scope of the present invention, it is possible to change, add, or convert each element of the above-described embodiment to a content that can be easily considered by those skilled in the art.

11, 31 Radio wave receiving means 12, 32 Tuning means 13, 33 Signal mixing means 14, 34 Intermediate frequency filter means 15, 35 Amplitude limiting amplification means 16, 36 Detection means 17, 37 Local oscillation frequency generating means 18, 38 Intermediate frequency filter Control means 19, 40, 52 Adjacent interference signal detection means 20, 41, 51 Comparison determination means 21 Modulation rate detection means 39 Intermediate frequency filter shift control means 42 Threshold variable coefficient generation means 43, 50 Spectrum information detection means 44 Signal demodulation analysis means 45 Adjacent interference removal means 46 Analog-digital conversion means 47 Fourier transform means 48 Orthogonal demodulation means 49 Carrier demodulation means 60, 62 Control signal generation means

Claims (1)

Differential frequency signal generating means for outputting a differential frequency between a tuning frequency obtained by tuning a desired signal from a received signal and a local oscillation frequency;
Intermediate frequency filter means for filtering the differential frequency signal and outputting an intermediate frequency;
Amplitude limiting amplification means for limiting the intermediate frequency to a desired amplitude using an amplitude limited amplification value;
Detection means for detecting a signal limited to the desired amplitude;
A threshold variable coefficient that varies the threshold according to the amplitude limited amplification value is generated, and the size of the lower sideband and the upper sideband in the occupied frequency bandwidth of the received signal, and the threshold variable coefficient Control signal generation for generating a first control signal for controlling the bandwidth of the intermediate frequency filter means and a second control signal for controlling the center frequency of the intermediate frequency filter means using a threshold value varied using Means,
Intermediate frequency filter control means for adjusting the bandwidth of the intermediate frequency filter means based on the first control signal;
An intermediate frequency filter shift control means for shifting the center frequency of the intermediate frequency filter means based on the second control signal.

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