JP4426948B2 - Transceiver - Google Patents

Description

  The present invention relates to a transceiver such as a transceiver, and more particularly to a transceiver capable of effectively eliminating an interference signal such as an image signal.

Patent Document 1 discloses a signal having a frequency that has an image relationship with respect to a channel selection frequency by providing a removal filter in front of the front end in order to eliminate an image signal as an interference signal in a dedicated receiver such as a radio or a television. Is removed with a removal filter (FIGS. 1 and 4 of Patent Document 1).
Japanese Utility Model Publication No. 4-88119

  When the transceiver receives radio waves of a predetermined channel, the maximum interference signal is not always a signal having an image frequency with respect to the frequency of the received signal. Depending on the place of use or the like, it may be slightly different from the image frequency, or a signal having a frequency different from the image frequency may be the maximum interference signal.

  The receiver of Patent Document 1 can remove the image signal, but cannot effectively remove the interference signal when there is a large interference signal different from the image signal.

  An object of the present invention is to provide a transceiver capable of effectively coping with an interference signal that is not only an image signal but also an interference signal that has the greatest adverse effect on the intermediate frequency signal, even if it is an image signal. Is to provide.

  According to the transmitter / receiver of the present invention, the removal filter whose adjustment of the removal frequency is adjustable is arranged in the front stage of the front end, and sends a signal obtained by attenuating the signal of the removal frequency from the reception signal to the front end. On the other hand, the front end is equipped with a band-pass filter and an intermediate frequency signal generator provided at a subsequent stage of the band-pass filter. In the interference signal frequency detection period, the operation of the removal filter is disabled, and the extraction frequency of the intermediate frequency signal generator is scanned over the pass frequency band of the bandpass filter. The relationship between the extraction frequency of the scanning range and the level of the intermediate frequency signal is related to the current reception environment. In other words, an extraction frequency at which the level of the intermediate frequency signal is high (extraction frequency excluding a specific reception frequency as the frequency of the own station) means that the level of the interference signal is high. In the reception period, the extraction frequency is set to the specific reception frequency, and the removal filter is controlled so that the maximum interference signal frequency among the interference signals passing through the bandpass filter becomes the removal frequency. As a result, during the reception period, the maximum jamming signal is prevented from entering the intermediate frequency signal generator, thereby improving the quality of the intermediate frequency signal.

  According to another transceiver of the present invention, the influence of an interference signal having a frequency outside the passband of the bandpass filter on the intermediate frequency signal is suppressed. That is, according to the other transmitter / receiver, the removal frequency of the removal filter is scanned outside the passband of the bandpass filter while the extraction frequency of the intermediate signal generator is maintained at the specific reception frequency in the interference signal frequency detection period. Then, the removal frequency of the removal filter that minimizes the level of the intermediate frequency signal is detected as the out-of-band interference signal frequency. In the reception period, the band interference signal frequency is set to be the removal frequency of the removal filter. As a result, the received signal having the out-of-band interference signal frequency is removed by the removal filter without passing through the band-pass filter, and the intermediate frequency signal generated by the intermediate frequency signal generator is generated from the interference signal having the out-of-band interference signal frequency. The impact is minimized.

  According to the present invention, an interference signal having a large influence in an actual reception environment is measured by scanning the extraction frequency of the intermediate frequency signal generator or scanning the removal frequency of the removal filter, The frequency of the signal recognized as the maximum interference signal based on the measurement is set as the removal frequency of the removal filter in the reception period of the specific reception frequency, and is removed by the removal filter. Therefore, not only the interference signal of the image frequency with respect to the extraction frequency in the intermediate frequency signal generator but also a case where a signal of other frequency is an interference signal can be effectively dealt with.

  FIG. 1 is a block diagram of a transceiver 10 that handles in-band jamming signals. The transceiver 10 includes a removal filter 11, a bandpass filter 12, an intermediate frequency signal generator 13, an intermediate frequency signal level detection unit 17, an extraction frequency scanning unit 18, an in-band jamming signal frequency detection unit 19, and a first control signal generation. Means 20 and extraction frequency setting means 21 are provided. The removal filter 11 has a removal frequency controlled by the first control signal, and outputs a signal obtained by attenuating the signal corresponding to the removal frequency from the received signal as an input signal. The bandpass filter 12 includes a specific reception frequency as a desired reception frequency in the pass frequency band, and passes only the signal in the pass frequency band from the output signal of the removal filter 11. The intermediate frequency signal generator 13 converts a signal component of the extracted frequency out of the output signal of the bandpass filter into an intermediate frequency signal. The intermediate frequency signal level detection means 17 detects the level of the intermediate frequency signal. In the interference signal frequency detection period, the extraction frequency scanning unit 18 scans the extraction frequency over the pass frequency band of the bandpass filter while keeping the removal filter in an inactive state. The in-band interfering signal frequency detecting means 19 uses the extracted frequency in the interfering signal frequency detection period as a result of scanning the extracted frequency having a frequency value different from the specific reception frequency and having the maximum intermediate frequency signal level. Detected as internal interference signal frequency. The first control signal generation means 20 generates the first control signal so that the removal frequency becomes the in-band interference signal frequency during the reception period. The extraction frequency setting means 21 sets the extraction frequency to a specific reception frequency during the reception period.

  The transceiver 10 and the below-described transceiver 30 (FIG. 2), the transceiver 40 (FIG. 3), and the transceiver 60 (FIG. 4) are typically portable transceivers. In the transceiver, a plurality of channels are prepared, and different specific reception frequencies are set corresponding to the respective channels. The received signal is, for example, a radio signal that arrives at the antenna. The removal filter 11 is composed of, for example, a circuit shown in FIG. The bandpass filter 12 and the intermediate frequency signal generator 13 constitute a front end 103 as shown in FIG. 5, for example. The intermediate frequency signal level detection means 17, the extraction frequency scanning means 18, the in-band interfering signal frequency detection means 19, the first control signal generation means 20 and the extraction frequency setting means 21 have their respective functions as a computer (example: FIG. 5 CPU 115) may be realized by executing a predetermined program, or may be realized by predetermined hardware. The intermediate frequency signal as the output of the intermediate frequency signal generator 13 is sent to the demodulator and demodulated, and then the amplitude level is adjusted by an amplifier (not shown), and then the sound is output from a speaker (not shown). Is output as

  Typically, the removal filter 11 does not completely remove the signal of the removal frequency. For example, as shown in FIG. 7, the removal filter 11 appropriately adjusts the RF level in a narrow frequency band including the cutoff frequency fc as the removal frequency. Attenuates. The band pass filter 12 is, for example, a frequency variable band pass filter.

  For the conversion in the intermediate frequency signal generator 13 from the extracted frequency signal to the intermediate frequency signal, for example, a local oscillator (eg, the local oscillator 108 in FIG. 5) is used, and the oscillation frequency of the local oscillator is adjusted to the extracted frequency. Thus, an intermediate frequency signal is generated. The level of the intermediate frequency signal detected by the intermediate frequency signal level detecting means 17 is called, for example, RSSI (Received Signal Strength Indicator). In order to keep the removal filter in the non-operating state during the interference signal frequency detection period, the extraction frequency scanning unit 18 (a) in addition to switching from the removal filter to a line that bypasses the removal filter, (b) One control signal can also be used. For example, if the first control signal is omitted or set to 0, the operation of the removal filter 11 becomes invalid, and signals of all frequencies pass through the removal filter 11 without being removed by the removal filter 11.

  In some cases, AGC (automatic gain control) is activated for the signal on the input side of the intermediate frequency signal generator 13 or the intermediate frequency signal. However, when the AGC is activated, the influence of the disturbing signal on the intermediate frequency signal. Therefore, it is necessary to cancel the AGC during the measurement period of the intermediate frequency signal level in the interference signal frequency detection period. Further, the in-band jamming signal frequency detection period is set in an environment in which a reception signal having a specific reception frequency is not received.

  Although the extraction frequency in the intermediate frequency signal generator 13 is different from the specific reception frequency as the desired reception frequency, the level of the intermediate frequency signal as the output of the intermediate frequency signal generator 13 is high. This means that the influence on the intermediate frequency signal when the frequency is the specific reception frequency, that is, the intermediate frequency signal related to the reception signal selected by the user is great. Therefore, during the reception period, the first control signal generation unit 20 generates the first control signal so that the removal frequency of the removal filter 11 becomes the in-band jamming signal frequency, and the in-band jamming signal frequency is The input to the intermediate frequency signal generator 13 through the band pass filter 12 is blocked, and the influence of the signal of the in-band interfering signal frequency on the intermediate frequency signal is suppressed.

  FIG. 2 is a block diagram of another transceiver 30 that handles in-band jamming signals. In the transmitter / receiver 30, the same elements as those of the transmitter / receiver 10 are designated by the same reference numerals, and description thereof is omitted. To describe the difference, the band-pass filter 12 is a frequency variable band-pass filter in which the center frequency of the pass frequency band is controlled by the second control signal. In the interference signal frequency detection period, the extraction frequency scanning unit 18 scans the extraction frequency while sending a second control signal whose center frequency is the specific reception frequency to the frequency variable bandpass filter.

  In a typical transceiver, the bandpass filter 12 is a frequency variable bandpass filter, and the frequency band of the pass signal of the bandpass filter 12 varies in relation to the extraction frequency of the intermediate frequency signal generator 13, A signal having an irrelevant frequency is suppressed from passing through the band-pass filter 12 as much as possible. The pass frequency band of the frequency variable bandpass filter is preferably set so that the reception frequency of the channel adjacent to the predetermined channel is out of the passband when the center frequency of the frequency variable bandpass filter is the reception frequency of the predetermined channel. Is. In the transmitter / receiver 30 in the reception period, the center frequency of the frequency variable bandpass filter is switched in relation to the extraction frequency of the extraction frequency scanning means 18. In the detection period, the extraction frequency scanning unit 18 operates so that the center frequency of the frequency variable bandpass filter is fixed to the specific reception frequency, and the extraction frequency is scanned over the pass bandwidth of the bandpass filter 12 in this fixed state. .

  In the developed type of the transceiver 30, the specific reception frequency is the channel frequency of the transceiver 30, and the in-band jamming signal frequency storage means 33 performs the specific reception when the in-band jamming signal frequency and the in-band jamming signal frequency are detected. The channel corresponding to the frequency is stored as a pair. The first control signal generation unit 20 is configured to receive the band when the in-band jamming signal frequency that is in a corresponding relationship with the channel selected by the user is stored in the in-band jamming signal frequency storage unit 33 during the reception period. The inner interference signal frequency is read, and a first control signal corresponding to the in-band interference signal frequency is generated.

  In a transceiver such as a transceiver, a plurality of typical specific reception frequencies are set as reception frequencies of a plurality of channels for transmission and reception. When using a transceiver in the same area on the same day, the user may temporarily use another channel and then use the channel that detected the interference signal frequency again. In a channel that has performed interference signal frequency detection (the channel will be referred to as “original channel”), the interference signal frequency is stored, so when switching to another channel and using the original channel again, The interference signal frequency paired with the original channel is read from the in-band interference signal frequency storage means 33, and the interference signal frequency is set as a removal frequency. Thereby, it is possible to avoid the appearance of the interference signal frequency detection period every time the original channel is returned.

  In another development of the transceiver 30, the in-band jamming signal frequency detecting means 19 detects the in-band jamming signal frequency corresponding to the specific reception frequency of each channel for all channels in one jamming signal frequency detection period. To do. The in-band jamming signal frequency storage means 33 stores each channel and the in-band jamming signal frequency for each channel in pairs for all channels.

  The in-band interfering signal frequency detection means 19 is arbitrary as to which channel the user selects for the current transmission / reception. Even when the user is continuously in the same area on the same day, the selected channel may be changed as appropriate according to the transmission / reception environment and the desire. The interference signal frequency detection period may be executed at regular time intervals or according to a user instruction, but it is troublesome that the interference signal frequency detection period repeatedly occurs. For example, prior to the use of the transceiver 30 in a predetermined area today (for example, at the start of this work or leisure), detection and storage of in-band jamming signal frequency for each channel is performed for all channels of the transceiver. Thus, after that, no matter what channel the user switches to, the interference signal frequency for the switching destination channel is already stored in the in-band interference signal frequency storage means 33. By using the removal frequency, the search for the in-band jamming signal frequency for each channel switching can be omitted.

  In yet another development of the transceiver 30. Fine adjustment of the removal frequency is performed. That is, the intermediate frequency signal generator 13 maintains the extraction frequency at the specific reception frequency during the removal frequency fine adjustment period. The first control signal generation means 20 performs the first control within a predetermined level range including the level with respect to the level of the first control signal that sets the removal frequency to the in-band interference signal frequency in the removal frequency fine adjustment period. Change the signal. The optimum control signal detecting means 35 detects, as the optimum control signal, the first control signal in which the level of the intermediate frequency signal is minimized as a result of the change in the first control signal during the removal frequency fine adjustment period. The first control signal generation means 20 generates an optimal control signal as the first control signal in the reception period.

  In the reception period of the specific reception frequency, when the specific reception frequency is the extraction frequency of the intermediate frequency signal generator 13, the frequency of the interference signal that has the maximum influence on the intermediate frequency signal is slightly shifted from the in-band interference signal frequency. There may be. Therefore, a removal frequency fine adjustment period is provided, and in the removal frequency fine adjustment period, the removal frequency is scanned within a predetermined range to find a removal frequency at which the level of the intermediate frequency signal is minimized, and this is used as the final removal frequency. By setting it, it is possible to achieve an optimal removal of interfering signals.

  Note that the removal frequency fine adjustment period is set in an environment in which a reception signal having a specific reception frequency is not received. This is because the removal frequency fine adjustment in an environment where a reception signal having a specific reception frequency as an extraction frequency is received hinders detection of an interference signal frequency due to the reception signal having the specific reception frequency.

  In the reception period, the extraction frequency setting means 21 can send a control signal related to a specific reception frequency not only to the intermediate frequency signal generator 13 but also to the bandpass filter 12 as a frequency variable bandpass filter. Thereby, in the reception period, the center frequency of the bandpass filter 12 as the frequency variable bandpass filter is controlled to the specific reception frequency.

  FIG. 3 is a block diagram of a transceiver 40 that automatically handles out-of-band jamming signals. The transceiver 40 includes a removal filter 41, a bandpass filter 42, an intermediate frequency signal generator 43, a removal frequency scanning unit 48, an out-of-band interference signal frequency detection unit 49, a first control signal generation unit 50, and an extraction frequency setting unit 51. Further, as an appropriate addition, an out-of-band interference signal frequency storage means 53 and an optimum extraction frequency detection means 55 are provided.

  The removal filter 41 controls the removal frequency by the first control signal, and outputs a signal obtained by attenuating the signal corresponding to the removal frequency from the received signal as the input signal. The bandpass filter 42 includes a specific reception frequency as a desired reception frequency in the pass frequency band, and passes only the signal in the pass frequency band from the output signal of the removal filter. The intermediate frequency signal generator 43 converts a signal component of the extraction frequency out of the output signal of the bandpass filter into an intermediate frequency signal. The intermediate frequency signal level detection means 47 detects the level of the intermediate frequency signal. The removal frequency scanning unit 48 changes the first control signal so that the removal frequency is scanned in a frequency band outside the pass frequency band while maintaining the extraction frequency at the specific reception frequency in the interference signal frequency detection period. The out-of-band jamming signal frequency detecting means 49 detects the removal frequency at which the level of the intermediate frequency signal is minimum as a result of the scanning of the removal frequency in the jamming signal frequency detection period as the out-of-band jamming signal frequency. The first control signal generation means 50 generates a first control signal whose removal frequency is an out-of-band interference signal frequency during the reception period. The extraction frequency setting means 51 sets the extraction frequency to the specific reception frequency during the reception period.

  The removal filter 41, the bandpass filter 42, the intermediate frequency signal generator 43, the intermediate frequency signal level detection means 47, and the extraction frequency setting means 51 are respectively the removal filter 11, the bandpass filter 12, and the intermediate frequency signal of the transceiver 30 described above. The generator 13, the intermediate frequency signal level detection means 17, and the extraction frequency setting means 21 have the same configuration, and the out-of-band interference signal frequency detection means 49, the first control signal generation means 50, and the out-of-band interference signal frequency storage means 53. The optimum extraction frequency detection means 55 is for the in-band jamming signal frequency detection means 19, the first control signal generation means 20, the in-band jamming signal frequency storage means 33, and the optimum control signal detection means 35 of the transceiver 30, respectively. The difference is that the processing target is changed from the in-band jamming signal frequency to the out-of-band jamming signal frequency. It is a body. In the transceiver 40, a removal frequency scanning unit 48 is provided instead of the extraction frequency scanning unit 18 of the transceiver 30.

  When the removal frequency of the removal filter 41 is scanned outside the pass band of the bandpass filter 42 while maintaining the extraction frequency in the intermediate frequency signal generator 43 at a specific reception frequency, for example, the frequency of a predetermined channel of the transceiver 40, The level of the frequency signal changes, and this level change is detected by the intermediate frequency signal level detection means 47. When the removal frequency is scanned outside the band-pass filter 42 and the level of the intermediate frequency signal is minimized, the removal frequency in the removal filter 41 is optimized, and the amount of noise mixed in the intermediate frequency signal Means less. Therefore, by setting the removal frequency at this time as an out-of-band interference signal frequency and setting the removal frequency during the reception period as an out-of-band interference signal frequency, a high-quality intermediate frequency signal can be generated in the reception period.

  Further, the out-of-band interference signal frequency detection period is set in an environment in which a reception signal having a specific reception frequency is not received. This is because it is clarified what the removal frequency has the least influence on the intermediate frequency signal.

  In the developed type of the transceiver 40, the specific reception frequency is the channel frequency of the transceiver 40, and the out-of-band interference signal frequency storage means 53 performs the specific reception when the out-of-band interference signal frequency and the out-of-band interference signal frequency are detected. The channel corresponding to the frequency is stored as a pair. When the out-of-band interference signal frequency that is correlated with the channel selected by the user is stored in the out-of-band interference signal frequency storage unit during the reception period, the first control signal generation unit 50 The jamming signal frequency is read, and a first control signal corresponding to the out-of-band jamming signal frequency is generated.

  For example, the transceiver 40 as a transceiver has a single channel or a plurality of channels for transmission and reception. The paired storage of the out-of-band jamming signal frequency and the channel corresponding to the specific reception frequency when the out-of-band jamming signal frequency is detected is preferably performed on all channels, and at least in at least one channel. It is done against. In this way, the out-of-band jamming signal frequency that is paired with the channel selected by the user for the current reception is read from the out-of-band jamming signal frequency storage means 53, and the out-of-band jamming signal frequency is removed by the filter 41. By using this removal frequency, it is possible to avoid the occurrence of an interference signal frequency detection period each time the channel is switched.

  The transceiver 10 (FIG. 1) or the transceiver 30 (FIG. 2) and the transceiver 40 (FIG. 3) may be integrated. In the integrated transceiver, the removal filter 11 and the removal filter 41 are connected in series, and an intermediate frequency signal is generated from a signal obtained by removing both an interference signal having an in-band interference signal frequency and an interference signal having an out-of-band interference signal frequency. can do. In the integrated transceiver, the functions of the bandpass filter 12, the intermediate frequency signal generator 13 and the intermediate frequency signal level detection means 17 and the functions of the bandpass filter 42, the intermediate frequency signal generator 43 and the intermediate frequency signal level detection means 47 are shown. Since the functions are the same, for example, the band-pass filter 42, the intermediate frequency signal generator 43, and the intermediate frequency signal level detection means 47 of the transmitter / receiver 40 are omitted.

  In a further development of the transceiver 40, the first control signal generating means 50 maintains the removal frequency at the out-of-band interference signal frequency during the extraction frequency fine adjustment period. The intermediate frequency signal generator 43 changes the extraction frequency in a predetermined range including the specific reception frequency in the extraction frequency fine adjustment period. The optimum extraction frequency detection means 55 detects the extraction frequency at which the level of the intermediate frequency signal is minimized as a result of the change in the extraction frequency during the extraction frequency fine adjustment period as the optimum extraction frequency. The extraction frequency setting means 51 sets the extraction frequency to the optimum extraction frequency during the reception period.

  Even if the removal frequency of the removal filter 41 is set to the out-of-band interference signal frequency, if the extraction frequency in the intermediate frequency signal generator 43 is slightly shifted, the level of the intermediate frequency signal is reduced, and the identification with less influence on the removal frequency is specified. The reception frequency may be found. In this way, the specific reception frequency can be optimized by fine adjustment of the extraction frequency, and the quality of the intermediate frequency signal is increased.

  The extraction frequency fine adjustment period is performed in an environment where the transceiver 40 does not receive a reception signal having a specific reception frequency. This is because it is necessary to accurately measure the influence of the interference signal having the removal frequency as the frequency on the intermediate frequency signal.

  FIG. 4 is a block diagram of a transceiver 60 that manually handles out-of-band jamming signals. The transceiver 60 includes a removal filter 61, a bandpass filter 62, an intermediate frequency signal level indicator 66, and a removal filter user operation member 67. The removal filter 61 outputs a signal in which the removal frequency is controlled by the first control signal and the signal corresponding to the removal frequency is attenuated from the received signal as the input signal. The bandpass filter 62 includes a specific reception frequency as a desired reception frequency in the pass frequency band, and passes only the signal in the pass frequency band from the output signal of the removal filter. The intermediate frequency signal generator 63 converts a signal component of the extracted frequency out of the output signal of the bandpass filter into an intermediate frequency signal. The intermediate frequency signal level indicator 66 displays the level of the intermediate frequency signal. The user operation member 67 for the removal filter adjusts the first control signal so that the removal frequency scans in a frequency band outside the pass frequency band while maintaining the extraction frequency at the specific reception frequency during the interference signal frequency detection period. In the reception period, the user can set the first control signal so that the removal frequency is set to an arbitrary value within the scanning range.

  The removal filter 61, the band pass filter 62, and the intermediate frequency signal generator 63 have the same configuration as the removal filter 41, the band pass filter 42, and the intermediate frequency signal generator 43 of the transceiver 40 (FIG. 3). In the interference signal frequency detection period, the user operates the removal filter user operation member 67 to maintain the extraction frequency of the intermediate frequency signal generator 63 at the specific reception frequency, while the removal frequency of the removal filter 61 passes. Scanned out of frequency band. During the scanning, the user visually observes the display of the intermediate frequency signal level indicator 66 and visually detects the removal frequency at which the level of the intermediate frequency signal is minimized. The detected removal frequency is set as an out-of-band interference signal frequency. In the reception period, the user operates the removal filter user operation member 67 again so that the removal frequency in the removal filter 61 becomes the out-of-band interference signal frequency. As a result, a high-quality intermediate frequency signal in which the influence from the out-of-band interference signal frequency is suppressed can be obtained.

  FIG. 5 is a configuration diagram of the transceiver 100. A radio wave as a reception signal is captured by the antenna 101 and input to the removal filter 102 as an electric signal. The removal filter 102 removes a signal portion having a predetermined removal frequency from the input signal and sends the remaining portion to the front end 103. The removal frequency of the removal filter 102 is controlled by a control signal Ca from the CPU 115. The front end 103 includes a frequency variable band pass filter (not shown) and a mixer 107. The frequency variable bandpass filter of the front end 103 is controlled by the control signal Cb from the CPU 115 for the center frequency of the pass frequency band. The local oscillator 108 is controlled in oscillation frequency by the CPU 115, and the mixer 107 mixes the output of the frequency variable bandpass filter and the oscillation signal of the local oscillator 108, and outputs an intermediate frequency signal as a mixed signal to IF (intermediate frequency). Output to the circuit 104. The IF circuit 104 detects the RSSI of the intermediate frequency signal and sends it to the CPU 115. Data is read from and written to the memories 118 and 119 by the CPU 115. The output of the IF circuit 104 is sent to a demodulation circuit (not shown), demodulated, and then appropriately amplified and output as a sound wave from a speaker (not shown).

  FIG. 6 is a detailed circuit diagram of the removal filter 102. The configuration itself of the input terminal 160 is well known. The input terminal 160 is connected to the output terminal 161 through capacitors 164 and 165. A connection point between the capacitor 164 and the capacitor 165 is grounded via a coil 166 and a varicap 167. The control terminal 162 is connected to a terminal on the non-ground side of the varicap 167 via a resistor 168. The control signal Ca from the CPU 115 is applied as a voltage to the control terminal 162, and the varicap 167 changes the capacitance according to the applied voltage of the control terminal 162.

  FIG. 7 shows the relationship between the RF level as the output of the removal filter 102 and its frequency. The cut-off frequency fc of the removal filter 102 increases / decreases depending on the capacitance of the varicap 167 and, therefore, the voltage applied to the control terminal 162. In FIG. 7, the RF level is lowered by 10 dB with respect to the non-attenuating frequency range at the cutoff frequency fc.

  FIG. 8 is a flowchart of a method for determining the cutoff frequency for the in-band jamming signal in the transceiver 100. In S180, the reception frequency fo is set. The transceiver 100 is equipped with a plurality of channels for transmitting and receiving radio waves with the counterpart transceiver, and the reception frequency fo corresponds to the frequency of one of the channels. In the transceiver 100, in S181, the center frequency of the frequency variable bandpass filter of the front end 103 is fixed to fo, and the extraction frequency of the front end 103 is changed from the frequency at one end of the pass frequency band of the frequency variable bandpass filter to the frequency at the other end. Scan. Specifically, the CPU 115 scans the oscillation frequency of the local oscillator 108 by changing the control voltage to the local oscillator 108, corresponding to the control signal Cb to be sent to the frequency variable bandpass filter of the front end 103. Let In S182, the oscillation frequency of the local oscillator 108 in the scanning process of S181, that is, the extracted frequency and RSSI data in the front end 103 is detected in association with each other and stored in the memory 118. In S183, the maximum RSSI is searched from the data stored in S182, and the extracted frequency associated with the maximum RSSI is searched for, and the extracted frequency is set as the in-band interference signal frequency. Note that the RSSI that is set to the maximum RSSI in S182 must have a frequency that is different from fo in the extracted frequency associated therewith. This is because fo must be extracted by the mixer 107 during the reception period and should not be removed as a removal frequency by the removal filter 102.

  In S184, the in-band jamming signal frequency found in S183 is determined as the cut-off frequency fc, and the control signal Ca is sent to the removal filter 102 so that the cut-off frequency fc in the removal filter 102 becomes the in-band jamming signal frequency. . In S184, the control signal Ca and the channel at this time are associated with each other and stored in the memory 119. The transceiver 100 has a plurality of channels, and the channel selected by the user is changed as appropriate, but this time, the channel associated with fc, which is the in-band jamming signal frequency, is the same time zone of the same day (example: : Daytime time zone and night time zone) and when it is used again in the same area, the corresponding cutoff from the channel based on the association information between the fc and the channel stored in the memory 119 By detecting the frequency fc and sending the control signal Ca corresponding to the cut-off frequency fc to the removal filter 102, the search for the in-band interference signal frequency again can be omitted.

  In S185, the cut-off frequency fc is finely adjusted. Specifically, at the front end 103, the extraction frequency and the center frequency of the frequency variable bandpass filter are fixed to fo, and the cutoff frequency fc of the removal filter 102 is moved within a predetermined narrow range including the initial fc. Then, the cutoff frequency fc at which the RSSI becomes the minimum value is used as the subsequent cutoff frequency fc.

  Each step of FIG. 8 is performed in an environment where the transceiver 100 does not receive a reception signal having the reception frequency fo from the counterpart transceiver.

  FIG. 9 is a flowchart of a method for automatically determining the cutoff frequency for the out-of-band jamming signal in the transceiver 100. In S200, the reception frequency fo is set. In S201, the center frequency of the frequency variable bandpass filter in the front end 103 and the extraction frequency of the mixer 107 are both fixed to fo, and the cutoff frequency fc of the removal filter 102 is scanned outside the pass frequency band of the frequency variable bandpass filter. To do. Specifically, the CPU 115 assumes that the control signal Cb sent to the frequency variable bandpass filter of the removal filter 102 corresponds to fo, the control voltage to the local oscillator 108 corresponds to fo, and supplies the control signal Cb to the removal filter 102. The control signal Ca is changed. In S202, each cutoff frequency fc and RSSI in the scanning process of S201 are detected in association with each other and stored in the memory 118.

  In S203, the cut-off frequency fc associated with the minimum RSSI is searched from the cut-off frequency fc stored in S202, and the cut-off frequency fc is set as an out-of-band interference signal frequency. In S204, the out-of-band interference signal frequency found in S203 is determined as the cutoff frequency fc, and the control signal Ca to the removal filter 102 is controlled so that the cutoff frequency fc in the removal filter 102 becomes the out-of-band interference signal frequency. To do. In S204, the out-of-band interference signal frequency and the channel at this time are associated with each other and stored in the memory 119. The transceiver 100 has a plurality of channels, and the channel selected by the user is changed as appropriate. However, the channel related to the out-of-band interference signal frequency detected this time is within the same area and is not much time from the survey time. When it is used again at a time that has not passed, the out-of-band jamming signal frequency is determined from the channel based on the association between the out-of-band jamming signal frequency stored in the memory 119 and the channel, and thereby the removal frequency scan is performed. The detection of the out-of-band interference signal frequency due to can be omitted.

  In S205, fine adjustment of the reception frequency fo is performed. Specifically, in the transceiver 100, fo is changed within a predetermined narrow range including the initial fo to search for the fo that minimizes the RSSI. Then, fo corresponding to the minimum RSSI is set to the subsequent fo.

  Note that S200 to S205 are performed in an environment where the transceiver 100 does not receive a reception signal of the reception frequency fo from the counterpart transceiver.

  FIG. 10 is a flowchart of a method for manually determining the cutoff frequency for out-of-band jamming signals in the transceiver 100. In order for the user to manually determine the cutoff frequency for the out-of-band interference signal, the transceiver 100 needs to be equipped with an fc adjustment operation member, an RSSI display, and an fo adjustment operation member. The fc scanning operation member manually changes the control signal Ca, and as a result, the removal frequency of the removal filter 102 changes. The RSSI display displays the RSSI measured in the IF circuit 104 to the user. The fo adjustment operating member manually changes the control signal Cb and the extraction frequency of the mixer 107. As a result, the center frequency of the frequency variable bandpass filter of the front end 103 and the extraction frequency of the mixer 107 change. Is.

  In S220, the user operates the fo adjustment operation member to set the reception frequency fo. Thereby, both the center frequency of the frequency variable bandpass filter and the extraction frequency of the mixer 107 are fixed to fo. In S221, the user operates the fc scanning operation member to scan the cutoff frequency fc of the removal filter 102 outside the pass frequency band of the frequency variable bandpass filter. In this scanning period, the user monitors the RSSI display and finds the position of the fc scanning operation member when the RSSI becomes maximum. In S222, the cutoff frequency fc corresponding to this operation position is determined as the out-of-band interference signal frequency. In S222, the user also operates another operation member, and associates the out-of-band interference signal frequency and the corresponding channel at this time with each other and stores them in the memory 119. Thereafter, the user operates the fc adjusting operation member to set the removal frequency of the removal filter 102 to the out-of-band interference signal frequency and to set the extraction frequency of the mixer 107 to the reception frequency fo. S223 is the same processing as S205 of FIG.

  Note that S220 to S223 are performed in an environment where the transceiver 100 does not receive a reception signal of the reception frequency fo from the counterpart transceiver.

It is a block diagram of the transmitter / receiver which copes with an in-band disturbance signal. It is a block diagram of another transmitter / receiver which copes with an in-band disturbance signal. It is a block diagram of a transceiver that automatically copes with out-of-band jamming signals. It is a block diagram of the transceiver which copes with an out-of-band disturbance signal manually. It is a block diagram of a transceiver. It is a detailed circuit diagram of a removal filter. It is a figure which shows the relationship between the RF level as an output of a removal filter, and its frequency. It is a flowchart of the determination method of the cut-off frequency for in-band jamming signals in a transceiver. It is a flowchart of the automatic determination method of the cut-off frequency for out-of-band interference signals in a transceiver. It is a flowchart of the manual determination method of the cut-off frequency for an out-of-band disturbance signal in a transceiver.

Explanation of symbols

10: transceiver, 11: removal filter, 12: band pass filter, 13: intermediate frequency signal generator, 17: intermediate frequency signal level detection means, 18: extraction frequency scanning means, 19: in-band jamming signal frequency detection means, 20: first control signal generation means, 21: extraction frequency setting means, 30: transceiver, 33: in-band jamming signal frequency storage means, 35: optimum control signal detection means, 40: transceiver, 41: removal filter, 42: band pass filter, 43: intermediate frequency signal generator, 47: intermediate frequency signal level detection means, 48: removal frequency scanning means, 49: out-of-band interference signal frequency detection means, 50: first X8 generation means, 51 : Extraction frequency setting means, 53: out-of-band interference signal frequency storage means, 55: optimum extraction frequency detection means, 60: transceiver, 61: removal filter, 2: bandpass filter, 63: intermediate frequency signal generator, 66: intermediate-frequency signal level indicator, 67: user operating member for removal filter.

Claims (9)

A removal filter for controlling the removal frequency by the first control signal and outputting a signal obtained by attenuating the signal component of the removal frequency from the received signal as an input signal;
A bandpass filter that includes a specific reception frequency as a desired reception frequency in a pass frequency band and passes only the signal in the pass frequency band from the output signal of the removal filter;
An intermediate frequency signal generator that converts a signal component of the extracted frequency into an intermediate frequency signal among the output signals of the bandpass filter,
Level detection means for detecting the level of the intermediate frequency signal;
Extraction frequency scanning means for scanning the extraction frequency over the pass frequency band of the bandpass filter while maintaining the removal filter in the non-operating state in the interference signal frequency detection period;
As a result of scanning of the extraction frequency in the interference signal frequency detection period, an extraction frequency having a frequency value different from the specific reception frequency and having the maximum intermediate frequency signal level is detected as an in-band interference signal frequency. Interference signal frequency detection means,
In the reception period, first control signal generating means for generating the first control signal so that the removal frequency becomes the in-band interference signal frequency, and in the reception period, the extraction frequency setting for setting the extraction frequency to a specific reception frequency means,
A transmitter / receiver characterized by comprising: The band pass filter is a frequency variable band pass filter in which a center frequency of a pass frequency band is controlled by a second control signal,
The extraction frequency scanning means scans the extraction frequency while sending the second control signal whose center frequency is the specific reception frequency to the frequency variable bandpass filter in the interference signal frequency detection period.
The transceiver according to claim 1. The specific reception frequency is the channel frequency of the transmitter / receiver, and the in-band interference signal frequency storage for storing the in-band interference signal frequency and the channel corresponding to the specific reception frequency when the in-band interference signal frequency is detected as a pair. And when the in-band jamming signal frequency corresponding to the channel selected by the user is stored in the in-band jamming signal frequency storage means during the reception period, the in-band jamming signal frequency is read out. The first control signal generating means for generating a first control signal corresponding to the in-band jamming signal frequency;
The transceiver according to claim 1, wherein the transmitter / receiver is provided. The in-band jamming signal frequency detecting means for detecting the in-band jamming signal frequency corresponding to the specific reception frequency of each channel for all channels in one jamming signal frequency detection period, and each channel for all channels The in-band jamming signal frequency storage means for storing a pair of in-band jamming signal frequencies for each channel;
The transmitter / receiver according to claim 3, further comprising: In the removal frequency fine adjustment period, the intermediate frequency generator that maintains the extraction frequency at a specific reception frequency,
In the removal frequency fine adjustment period, the first control for changing the first control signal within a predetermined level range including the level with respect to the level of the first control signal that sets the removal frequency to the in-band interference signal frequency. Signal generating means,
Optimal control signal detecting means for detecting, as an optimal control signal, the first control signal that minimizes the level of the intermediate frequency signal as a result of the change in the first control signal during the removal frequency fine adjustment period, and the optimal control signal during the reception period The first control signal generating means for generating the first control signal as a first control signal,
The transmitter / receiver according to claim 1, wherein the transmitter / receiver is provided. A removal filter for controlling the removal frequency by the first control signal and outputting a signal obtained by attenuating the signal component of the removal frequency from the received signal as an input signal;
A bandpass filter that includes a specific reception frequency as a desired reception frequency in a pass frequency band and passes only the signal in the pass frequency band from the output signal of the removal filter;
An intermediate frequency signal generator that converts a signal component of the extracted frequency into an intermediate frequency signal among the output signals of the bandpass filter,
Level detection means for detecting the level of the intermediate frequency signal;
A removal frequency scanning means for changing the first control signal so that the removal frequency is scanned in a frequency band outside the pass frequency band while setting the extraction frequency to a specific reception frequency in the interference signal frequency detection period;
Out-of-band jamming signal frequency detection means for detecting a removal frequency that minimizes the level of the intermediate frequency signal as an out-of-band jamming signal frequency as a result of scanning of the removal frequency in the jamming signal frequency detection period;
A first control signal generating means for generating a first control signal whose removal frequency becomes the out-of-band interference signal frequency in the reception period; and an extraction frequency setting means for setting the extraction frequency to a specific reception frequency in the reception period;
A transmitter / receiver characterized by comprising: The specific reception frequency is a channel frequency of the transmitter / receiver, and the out-of-band interference signal is stored by pairing the out-of-band interference signal frequency and the channel corresponding to the specific reception frequency when the out-of-band interference signal frequency is detected. And when the out-of-band jamming signal frequency corresponding to the channel selected by the user is stored in the out-of-band jamming signal frequency storing means during the reception period, the out-of-band jamming signal frequency is The first control signal generating means for reading and generating a first control signal corresponding to the out-of-band interference signal frequency;
The transmitter / receiver according to claim 6, further comprising: In the extraction frequency fine adjustment period, the first control signal generating means for maintaining the removal frequency at the out-of-band interference signal frequency,
In the extraction frequency fine adjustment period, the intermediate frequency signal generator that changes the extraction frequency in a predetermined range including a specific reception frequency,
Optimal control signal detection means that detects the extraction frequency that minimizes the level of the intermediate frequency signal as a result of changes in the extraction frequency during the extraction frequency fine adjustment period, and the extraction frequency is set to the optimal extraction frequency during the reception period The extraction frequency setting means
The transceiver according to claim 6 or 7, characterized by comprising: A removal filter for controlling the removal frequency by the first control signal and outputting a signal obtained by attenuating the signal component of the removal frequency from the received signal as an input signal;
A bandpass filter that includes a specific reception frequency as a desired reception frequency in a pass frequency band and passes only the signal in the pass frequency band from the output signal of the removal filter;
An intermediate frequency signal generator that converts a signal component of the extracted frequency into an intermediate frequency signal among the output signals of the bandpass filter,
An intermediate frequency signal level indicator that displays the level of the intermediate frequency signal, and the removal frequency scans in a frequency band outside the pass frequency band while maintaining the extraction frequency at a specific reception frequency in the interference signal frequency detection period. Allowing the user to adjust the first control signal, and allowing the user to set the first control signal so that the removal frequency is set to an arbitrary value in the scanning range during the reception period. Removal filter user operation member,
A transmitter / receiver characterized by comprising:

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