JP2006222819A - Adjacent band monitor device in radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always monitor and confirm an electric wave state like the occurrence of interfering or pileup in an adjacent band without influencing essential reception band signals in a radio receiver. <P>SOLUTION: A signal in the input side of a band filter 9 which sets a passband width (for example, 300 Hz) corresponding to an electric wave form (for example, CW) is branched and is filtered by a band filter 21 having a wider passband width (for example, 2.7 kHz) than the band filter 9, and a signal resulting from intermediate frequency amplification and detection of an output signal of the band filter 9 is subtracted from a signal resulting from intermediate frequency amplification and detection of an output signal of the band filter 21 by a differential amplifier 24 to obtain a difference signal, and an S meter 25 is deflected by the difference signal. Center frequencies of band filters 9 and 21 are set to a reception frequency, and the difference signal shows a radio field intensity of a band adjacent to a reception band, and therefore, the electric wave state of the adjacent band can be monitored and confirmed by the S meter 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a proximity band monitoring device in a radio receiver, and relates to a configuration for always monitoring and confirming a radio wave condition in a band close to an operation band.

In amateur radio communications, the dynamic range and selectivity in the performance of a radio receiver are more important because they are not operated at a pre-assigned frequency like commercial radio.
Here, the dynamic range indicates how much strong signal is present in a close band during reception of a weak signal, and cross modulation occurs, and selectivity is intended to be received. This indicates how far radio waves can be selectively separated and received, that is, how far away the frequencies of signals in adjacent bands are not disturbed.

According to the following Non-Patent Document 1, since the reception cannot be performed comfortably even if the selectivity is too narrow or too wide, the following values are likely to be appropriate for each communication method.
[SSB communication with local station: 3 kHz], [SSB communication with DX station: 2.2 kHz], [General CW communication: 500 Hz], [CW communication with DX station: 200 Hz], [RTTY communication: 250- 500Hz], [UHF FM communication: 15kHz]

Edited by Japan Amateur Radio Federation “JARL Amateur Radio Handbook” CQ Publishing Company April 20, 1997 p. 263

By the way, it is desirable for a radio receiver to demodulate and reproduce only the radio wave in the desired band without being disturbed by the radio wave in the near band as described above. There are many cases.
For example, if you want to check how much jamming signal is generated in the proximity band, or if you operate a radio station in a rare area and receive calls from a large number of stations, the pile-up You may want to monitor / confirm the situation.
Conventionally, in such a case, a method of empirically estimating from a change in voice output or an indication value of the S meter by widening the reception band or shifting the reception center frequency has been taken.
However, depending on the radio wave conditions in the adjacent band, significant interference occurs, and the signal level of the original reception band is attenuated. Therefore, a delicate knob operation is required, and the voice output and the indication value of the S meter are in the reception band. Since the signal is included, it is not easy to check the status of the adjacent band.
Therefore, in view of the above problems, the present invention has been created for the purpose of providing a wireless receiver that can always check a radio wave condition in a band close to the reception band from an indicator during reception.

  According to a first aspect of the present invention, in the wireless receiver, an input signal to a first band-pass filter unit provided at a subsequent stage of the frequency conversion unit and having a pass bandwidth corresponding to the selected radio wave format is input to the first band. A second band filter means for filtering with a wider pass bandwidth than the pass band width of the filter means; a set reception frequency; and a center of each pass bandwidth of the first band filter means and the second band filter means A filter control means for changing the frequency to be the same so as to be the same, and a difference for obtaining a difference obtained by subtracting a signal after filtering by the first band filter means from a signal after filtering by the second band filter means And a proximity band monitoring device in a radio receiver, comprising: an indicating means for indicating a radio wave intensity in a band close to a reception frequency band based on an output of the difference means According to the.

In general, in a radio receiver, a received signal input from an antenna is amplified by a high frequency amplification unit, frequency-converted by one stage or a plurality of stages, and then filtered by a band filter corresponding to the reception frequency band for detection. .
The first band filter means corresponds to the band filter. In the present invention, the received signal on the input side of the first band filter means is filtered by the second band filter means.
Here, the pass bandwidth of the second band filter means is set wider than the pass bandwidth of the first band filter means, and the reception frequency set by the filter control means and the first and second band filters. The central frequency of each pass bandwidth in the means is changed in conjunction so as to be the same.
Therefore, the output of the difference means corresponds to the intensity of the received signal in the adjacent band on both sides of the pass band of the first band filter means, and indicates this as the radio wave intensity by the instruction means, thereby affecting the original reception band. Without giving it, you can always check the radio wave condition in the proximity band.
The proximity band monitoring device of the present invention can be configured as an analog circuit, but it can also be configured by signal processing by a DSP (Digital Signal Processor) other than the instruction unit.

According to a second aspect of the present invention, in the wireless receiver having two systems from the high frequency amplifier to the final frequency converter, the circuit of one system is used for original reception and detection, and the frequency in the circuit is used. A filter having a pass bandwidth corresponding to the selected radio wave format is provided as a first band filter means provided at a subsequent stage of the conversion unit, and is provided at a subsequent stage of the frequency conversion unit in the circuit of the other system. Second bandpass filter means for filtering with a wider passband than the passbandwidth of the bandpass filter means;
A filter that changes the reception frequency set identically in the two systems of circuits and the center frequency of each pass bandwidth of the first band-pass filter means and the second band-filter means so as to be the same. A control means, a difference means for obtaining a difference obtained by subtracting a signal after filtering by the first band filter means from a signal after filtering by the second band filter means, and a reception frequency band based on the output of the difference means According to another aspect of the present invention, there is provided a proximity band monitoring device in a radio receiver, comprising: an instruction unit that indicates a radio wave intensity in a band adjacent to the wireless receiver.

This invention obtains the same function as the first invention by using one of the two circuits from the high frequency amplifier to the final frequency converter in the wireless receiver. It is.
In this case, the second band-pass filter means is provided at the subsequent stage of the frequency converter of the final stage in the circuit of the other system, and the two circuits are set to the same reception frequency, and the filter control means The only characteristic is that the reception frequency and the center frequency of the pass bandwidth in the first and second band filter means are changed so as to be the same, and other configurations and operating principles are as follows. This is similar to the first invention.

In each of the above inventions, the difference means obtains a difference obtained by subtracting the signal after filtering by the first band filter means from the signal after filtering by the second band filter means. Does not mean a direct output of each bandpass filter means, but also includes a signal that has been subjected to intermediate frequency amplification processing or a signal that has been subjected to detection processing.
Therefore, in each of the above-mentioned inventions, the signal after filtering by the first band-pass filter means is used as the output signal of the intermediate frequency amplifying means subsequent to the first band-pass filter means, and the signal after the second band-pass filter means. An intermediate frequency amplifying means is provided, and the difference means is subtracted from the output signal of the intermediate frequency amplifying means subsequent to the first band filter means from the output signal of the intermediate frequency amplifying means provided after the second band filter means. It may be a means for obtaining the difference.
The signal after the filtering by the first band-pass filter means is made a signal after being detected by the detecting means from the first band-pass filter means through the intermediate frequency amplifying means, and is intermediate in the subsequent stage of the second band-filter means. A frequency amplifier and a detection means are provided, and a difference obtained by subtracting the output signal of the detection means on the first band filter means side from the output signal of the detection means provided on the second band filter means side with the difference means is obtained. It may be a means.

  In each of the above inventions, an S meter can be applied as the indicating means, and the S meter and the S meter indicating the radio field intensity of the received signal based on the output signal of the first detecting means are provided on the operation panel surface. If it is provided side by side, it is possible to compare the radio field intensity of the original received radio wave with the radio field intensity of the adjacent band.

  The proximity band monitoring device in the wireless receiver of the present invention can always monitor and confirm the radio wave state such as the jamming radio wave and the occurrence of pile-up in the near band without affecting the original reception band signal.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, FIG. 1 is a block diagram of a radio receiver to which the proximity band monitoring device of the present invention is applied. 1 is an antenna, 2 is a high frequency amplifier, 3 is a PLL synthesizer, 4 is an input signal and a local oscillation signal of the PLL synthesizer 3. 5 is a band filter for selecting one of the two signals generated by the mixer 4, and 6 is an intermediate frequency amplifier for amplifying the signal that has passed through the band filter. 7 is a local oscillator, 8 is a mixer that mixes the output signal of the intermediate frequency amplifier 6 and the local oscillation signal of the local oscillator 7 to obtain a low frequency signal, and 9 is a bandpass filter that is switched according to the set radio wave type. 10 is an intermediate frequency amplifier that amplifies the signal that has passed through the bandpass filter 9, 11 is a detector, 12 is a low frequency amplifier, and 13 is a speaker. Reception and reproduction circuit version method is configured.

The feature of this radio receiver is that the output signal of the mixer 8 is also output to a circuit comprising a band filter 21, an intermediate frequency amplifier 22 and a detector 23 which are configured separately from the receiving / reproducing circuit. The output of the detector 23 and the output of the detector 11 on the receiving / reproducing circuit side are input to the differential amplifier 24, and the S meter 25 is activated by the output signal of the differential amplifier 24.
Here, the band filter 21 is switched according to the radio wave type in the same manner as the band filter 9, and the pass band width is set wider than the pass band width of the band filter 9.
The intermediate frequency amplifier 22 and the detector 23 have the same characteristics as the intermediate frequency amplifier 10 and the detector 11 on the receiving / reproducing circuit side, respectively.
Further, when the reception frequency is selected by operating the knob of the operation unit 14 or the like, the control unit 15 controls the local oscillation frequency of the PLL synthesizer to be tuned to the selected frequency as well as the normal receiver, and in the band filter 9 The center frequency of the pass band is set as the selected frequency. In this radio receiver, the center frequency of the pass band of the band filter 21 is also set as the selected frequency.
The output of the detector 11 on the receiving / reproducing circuit side is also input to another S meter 26.

Based on the above configuration, when the radio wave format: CW reception mode is set from the operation unit 14, the control unit 15 sets the band filter 9 as a filter having a pass bandwidth of 300 Hz and passes through the band filter 21. A filter with a bandwidth of 2.4 kHz is set.
2A and 2B show the frequency characteristics of the band filter 9 and the band filter 21, respectively. When the reception frequency is adjusted and set by the operation unit 14 and a tuned radio wave is received, the band filters 9, 21 are shown. Based on each frequency characteristic, a signal including frequency components distributed in a narrow bandwidth 300 Hz and a wide bandwidth 2.4 kHz around the set reception frequency Cf is passed.

Accordingly, the output signals are amplified by the intermediate frequency amplifiers 10 and 22 having the same characteristics, then detected by the detectors 11 and 23, and the signal output of the detector 23 by the differential amplifier 24 (on the band filter 21 side). When the output obtained by subtracting the output signal of the detector 11 (the signal on the band filter 9 side) from the signal) is obtained, the output signal is the same as that obtained by filtering with a band filter having frequency characteristics as shown in FIG. Is obtained.
In other words, if both signal bands are included in both outer bands (bandwidth: 1.05 kHz) of the bandwidth 300 Hz centered on the reception frequency Cf, the S meter 25 swings greatly, and when the signal component is small, the vibrations occur. Becomes smaller.

In other words, it is possible to constantly monitor the radio wave conditions of the both outer bands (close bands) when there is a high possibility that jamming radio waves are generated or calls from a large number of stations are received. Since the indicated value of the S meter shows a large value, the situation can be visually confirmed.
In particular, when the reception mode of the radio wave format: CW is set, since the reception state is as narrow as 300 Hz as described above, the radio wave condition in the near band is a concern. According to the bandwidth monitoring device, it is always possible to easily monitor and confirm.
In addition, since the reception / reproduction state of the signal in the original reception band is not affected at all, there is no inconvenience that it is difficult to hear the received sound.
If the S meter 25 and the S meter 26 are provided on the operation panel surface, it is possible to compare the radio wave intensities of the reception band and the near band, and to obtain monitoring information that is easier to understand.

In the radio receiver of FIG. 1, the output signals of the detectors 11 and 23 are input to the differential amplifier 24. As shown in FIGS. 3A and 3B, the intermediate frequency amplifiers 10 and 22 are input. Alternatively, the outputs of the band-pass filters 9 and 21 may be input to the differential amplifier 24. Similarly, the radio wave condition in the close band can be monitored and confirmed from the S meter 25.
In those cases, there is an advantage that the detector 23 and the intermediate frequency amplifier 22 which are necessary in the circuit of FIG.

Next, FIG. 4 is a block diagram when the proximity band monitoring apparatus of the present invention is applied to a radio receiver having a special configuration having two receivers.
This radio receiver has a sub-reception circuit in addition to the main circuit similar to the reception / reproduction circuit of FIG. 1, and the sub-reception circuit has the same configuration as the main circuit from the high-frequency amplifier 32 to the detector 41. However, as for the band filter 39, a filter having a wider pass bandwidth than the pass band width of the band filter 9 on the main circuit side set according to the selected radio wave format is selectively switched. For example, when the reception mode of the radio wave format: CW is selected as described above, a filter having a pass bandwidth of 300 Hz is selected as the band filter 9, and a pass bandwidth of 2.4 kHz is selected as the band filter 39. Are selected.
When a reception frequency is selected by operating the knob of the operation unit 14 or the like, the control unit 15 synchronizes the main circuit and the sub reception circuit to the reception frequency, and each of the pass bands in the band filters 9 and 39 is tuned. The center frequency is set to the reception frequency.

The output signals of the detectors 11 and 41 of the main circuit and the sub reception circuit are input to the differential amplifier 23. The differential amplifier 23 is a differential signal obtained by subtracting the output signal of the detector 11 from the output signal of the detector 41. And the signal is output to the S meter 25.
Therefore, compared with the wireless receiver of FIG. 1, the sub receiver circuit is merely used when there is a sub receiver circuit, and is functionally similar. I can confirm.
4, the output signals of the intermediate frequency amplifiers 10 and 40 and the output signals of the bandpass filters 9 and 39 are also received in the same manner as the circuits shown in FIGS. 3A and 3B. It may be configured to output to the differential amplifier 23.

It is a block diagram of the radio receiver to which the proximity band monitoring device of the present invention is applied. (A) is a frequency characteristic diagram of a bandpass filter (passband width: 300 Hz), (B) is a frequency characteristic diagram of a bandpass filter (passband bandwidth: 2.4 kHz), and (C) is a bandpass filter (passband bandwidth: 2). FIG. 4 is a frequency characteristic diagram of a virtual band filter having a filter function equivalent to a case where a differential signal obtained by subtracting a signal that has passed through a bandpass filter (passband width: 300 Hz) from a signal that has passed through .4 kHz is obtained. (A) is a block diagram showing a circuit portion when an output signal to the differential amplifier is obtained from the output side of the intermediate frequency amplifier, and (B) is a block diagram showing a circuit portion when obtained from the output side of each bandpass filter. is there. It is a block diagram at the time of applying the proximity band monitoring apparatus of this invention to the radio | wireless receiver of a special structure which has two receiving parts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... High frequency amplifier, 3 ... PLL synthesizer, 4 ... Mixer, 5 ... Band filter, 6 ... Intermediate frequency amplifier, 7 ... Local oscillator, 8 ... Mixer, 9 ... Band filter, 10 ... Intermediate frequency amplifier , 11 ... detector, 12 ... low frequency amplifier, 13 ... speaker, 14 ... operation part, 15 ... control part, 21 ... band filter, 22 ... intermediate frequency amplifier, 23 ... detector, 24 ... differential amplifier, 25 ... S meter, 26 ... S meter, 32 ... high frequency amplifier, 33 ... PLL synthesizer, 34 ... mixer, 35 ... band filter, 36 ... intermediate frequency amplifier, 37 ... local oscillator, 38 ... mixer, 39 ... band filter, 40 ... intermediate frequency amplifier, 41 ... detector.

Claims (5)

In the wireless receiver
An input signal to the first band filter means provided at the subsequent stage of the frequency conversion unit and having a pass band width corresponding to the selected radio wave format is wider than the pass band width of the first band filter means. Second bandpass filter means for filtering at;
Filter control means for changing the reception frequency to be set in conjunction with each other so that the center frequencies of the pass bandwidths of the first band filter means and the second band filter means are the same;
Difference means for obtaining a difference obtained by subtracting the signal after filtering by the first band filter means from the signal after filtering by the second band filter means;
A proximity band monitoring device in a radio receiver, comprising: an instruction unit that indicates a radio wave intensity in a band close to a reception frequency band based on an output of the difference unit. In a radio receiver having two systems from a high frequency amplifier to a final frequency converter,
The first band filter means uses a filter of one system for original reception / detection and a filter having a pass bandwidth corresponding to the selected radio wave format provided at the subsequent stage of the frequency converter in the circuit. age,
A second band filter means provided at a subsequent stage of the frequency conversion unit in the circuit of the other system, and filtering with a wider pass bandwidth than the pass band width of the first band filter means;
A filter that changes the reception frequency set identically in the two systems of circuits and the center frequency of each pass bandwidth of the first band-pass filter means and the second band-filter means so as to be the same. Control means;
Difference means for obtaining a difference obtained by subtracting the signal after filtering by the first band filter means from the signal after filtering by the second band filter means;
A proximity band monitoring device in a radio receiver, comprising: an instruction unit that indicates a radio wave intensity in a band close to a reception frequency band based on an output of the difference unit.   The signal after filtering by the first band filter means is an output signal of the intermediate frequency amplification means subsequent to the first band filter means, and the intermediate frequency amplification means is provided after the second band filter means, The difference means is a means for obtaining a difference obtained by subtracting the output signal of the intermediate frequency amplification means subsequent to the first band filter means from the output signal of the intermediate frequency amplification means provided downstream of the second band filter means. The proximity band monitoring apparatus in the radio receiver according to claim 1.   The signal after filtering by the first band-pass filter means is a signal that has been detected by the detection means from the first band-pass filter means through the intermediate-frequency amplification means, and has an intermediate frequency after the second band-pass filter means. An amplifier and detection means, and the difference means obtains a difference obtained by subtracting the output signal of the detection means on the first band filter means side from the output signal of the detection means provided on the second band filter means side The proximity band monitoring device in the radio receiver according to claim 1 or 2. The instructing means is an S meter, and the S meter and an S meter indicating the radio field intensity of the received signal based on the output signal of the first detecting means are provided on the operation panel surface. The proximity band monitoring apparatus in the radio receiver according to claim 2, 3 or 4.

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