JPH0264484A - Receiving apparatus - Google Patents

Abstract

PURPOSE:To detect frequency difference when a plurality of high frequency signals having a frequency interval of a channel dividing frequency width or less arrive simultaneously by providing a frequency difference/time difference converting means and a simultaneous arrival signal frequency difference judge means. CONSTITUTION:A plurality of signals approximate in frequency arriving at the same time are distributed to a frequency difference/time difference converting means 31 by a distributor 21 and multiplied by the output signal of a sweep oscillator 23 by a mixer 22 to become a chirp signal. The chirp signal passes through band-pass filters (BPF) 251-25n through a distributor 24 to be applied to a pulse compression filters 261-26n and the outputs of said pulse compression filters are detected by the detectors 271-27n of a simultaneous arrival signal frequency difference judge means 32 to be applied to pulse counters 291-29n through amplifiers 281-28n. The counters 291-29n count the number of compression pulses during one sweep period of the sweep oscillator 23 and the count values are supplied to a judge circuit 30 and, when the count values are 2, the frequency difference of a plurality of the simultaneously arriving signals can be detected from a time interval by time interval measuring circuits 351-35n.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a channel division receiving device for detecting parameters of a signal arriving from a radio wave source, and particularly relates to one used for detecting a plurality of radar signals arriving at the same time. .

[Conventional technology]

Channel division receivers have recently attracted attention as receivers that can simultaneously detect a large number of signals arriving simultaneously over a wide frequency band. For example, FIG. 5 is a block diagram showing the configuration of a conventional channel division receiving device disclosed in Japanese Patent Application No. 62-12819 developed by the present applicant. amplifier, 3
4 and 5 are tuners that convert the incoming signal that has passed through the receiving antenna 1 and preamplifier 2 into a predetermined intermediate frequency signal;
6 is a mixer and a variable local oscillator that constitute the tuner 3, respectively, and 6 is a tuning control circuit that controls the tuner 3. Further, 7 is a bandpass filter, 8 is an intermediate frequency amplifier, and 9 is a channel division receiver. In this channel division receiver 9, 1O211 is a channel division reception means, IO is a distributor, and 11 is a filter bank.

The filter bank 11 is a channel (hereinafter referred to as "ch").

If the number is n (n is a positive integer), it is composed of a channel division filter consisting of n bandpass filters, and 156. ..., 157 are each ch.

3. ..., ch,, l filter. The band characteristics of the filter bank 11 are as shown in FIG. 6, for example.

17I, . . . , 17.1 are amplifiers, 181 . . . , 187 are detectors, and these are provided for each channel.

19 is a pulse specification detection circuit, and a detector 181°...,
18. The detection video output of l is converted into analog/digital (A
/D) Convert the frequency of the incoming radar signal.

The signal level (if the arriving signal is a continuous wave or a pulse) is detected, and if the arriving signal is a pulse, the pulse specifications such as pulse width, pulse interval, and pulse arrival time are also detected. A buffer circuit (FIFO) 20 temporarily stores the digital data detected by the pulse specification detection circuit 19.

Next, the operation will be explained. In the channel division receiving apparatus shown in FIG. 5, a frequency band is divided into a plurality of continuous subdivisions (channels) by a distributor 10 and a filter bank 11, and reception is performed. Frequency measurement is performed by determining which channel has input. That is, the detector 18. .

18□,...,18. Depending on the signal level of the output video signal, a channel with band characteristics as shown in Fig. 6.
, ..., ch,, filter 15I, ..., 15
The amplitude (level) comparison circuit in the pulse specification detection circuit 19 compares the output response levels of 7 and detects the channel with the maximum response level, detects the signal (detects the presence), and calculates the approximate frequency corresponding to the channel number. (The accuracy is defined as the interval between the center frequencies of two adjacent channel division filters.) When measuring the detailed frequency, the amplitude comparison circuit in the pulse specification detection circuit 19 determines the signal level difference between channels, and the corresponding frequency is determined from the signal level difference, so-called frequency interpolation. Further, pulse specifications are detected by a pulse specifications detection circuit 19, and the detected pulse specifications and frequency are stored in a buffer circuit 20.

When a plurality of signals arrive at the same time at the channel division receiving device shown in FIG. Specifications are detected.

[Problem to be solved by the invention]

Since the conventional channel division receiving device is configured as described above, ch,...,ch,, filter 1
5. , . . . When multiple signals whose frequencies are close to each other at the same level or less than the frequency array spacing of 157 arrive at the same time, each filter in the filter bank 11 separates the signals and detects the presence of multiple waves and their frequency differences. difficult to detect,
To detect multiple waves, it is necessary to perform a special output response level comparison between channels assuming the composite signal level of multiple waves, which poses problems such as complex signal processing. Ta.

This invention has been made to solve the problems of the conventional ones as described above, and provides a receiving device that can easily detect signals with multiple frequencies arriving at the same time and that are close to each other, and can also determine the frequency difference between them. The purpose is to

[Means to solve the problem]

The receiving device according to the present invention converts the frequency difference between the simultaneously arriving multiple signals into a time difference when a plurality of high frequency signals whose frequency intervals are equal to or less than the channel dividing frequency width arrive at the same time within the reception frequency band of the channel division receiving device. Based on the time difference, it is detected that multiple signals with close frequencies arrive simultaneously, and the frequency difference is determined from the time difference.

[Effect]

In this invention, the receiving device determines the time difference based on the frequency difference between the plurality of waves using the simultaneous arrival signal determination means, and determines that the simultaneous arrival occurs when the plurality of high frequency signals whose frequency intervals are equal to or less than the channel division frequency width arrive at the same time. , and detect the frequency difference between the simultaneously arriving signals.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a receiving apparatus according to an embodiment of the present invention, in which l is a receiving antenna, 2 is a preamplifier, 3 is a receiving antenna 1. A tuner that converts an incoming signal that has passed through the preamplifier 2 into a predetermined intermediate frequency signal, and 4 and 5 are a mixer and a variable local oscillator that constitute the tuner 3, respectively;
6 is a tuning control circuit for controlling the tuner 3; 7
is a bandpass filter, 8 is an intermediate frequency amplifier, and 9 is a channel division receiver.

In this receiver 9, 10 and 11 are channel division receiving means, 10 is a distributor, and 11 is a filter bank. The filter bank 11 is composed of channel division filters consisting of n bandpass filters, where the number of channels (hereinafter also referred to as ch) is n (n is a positive integer), and 151. ...157 are respectively ch h,,,...
, ch, . The band characteristics of the filter bank 11 are as shown in FIG. 6, for example. 171
．． . . , 17, , are amplifiers, 185 . ...
, 18 are detectors, each of which is provided for each channel. 19 is a pulse specification detection circuit;
Detector 185. ..., the detection video output of 187 is converted to analog/digital (A/D) to obtain the frequency, signal level (if the arriving signal is continuous wave CW or pulse) of the arriving radar signal, and pulse specifications (of the arriving signal Cajalus). case) i.e. pulse width, pulse interval.

Detect the pulse arrival time. 20 is a banfa circuit (FI
FO), the digital data detected by the pulse specification detection circuit 19 is temporarily stored. 21 is a distributor which distributes the intermediate frequency signal to the channel division receiver 9 and the frequency difference/time difference conversion means 31 described below.

Further, 22 is a mixer, 23 is a sweep oscillator, -24 is a distributor, 25I, . . . , 257 is a bandpass filter, 261, .
..., 26. , is a pulse compression filter, which includes the mixer 22, the sweep oscillator 23, the distributor 24, and the bandpass filter 2.
5I,..., 25°, pulse compression filter 261.・
. . , 26 constitute the frequency difference time difference converting means 31. 27I,...,27. .

is a detector, 285. ..., 287 is an amplifier, 29. .

..., 29. , is a pulse counter, 30 is a judgment circuit,
351, . . . , 35fi are time interval measurement circuits,
This detector 271. ..., 27. , amplifier 28. .

..., 28. ,, pulse counter 298 . ...,,
29. , determination circuit 30, time interval measurement circuit 352.・・・
. , 359 constitute the simultaneously arriving signal frequency difference determining means 32.

Next, the operation will be explained. First, when one signal arrives at the receiving device in Fig. 1 and the frequency is ch1+ ``'+
ch, n filter 151, . . . , 15. l
When a plurality of signals separated by at least the same frequency array interval arrive at the same time, they are received using the filter bank 11, which is channel division reception means, and its operation is similar to that of the conventional channel division reception device shown in FIG. The operation is similar to that in .

Next, the receiving device shown in Fig. 1 receives the frequencies chl, . . .

ch, filter 151. ..., 15. The operation in the case where a plurality of signals that are close to each other at the frequency arrangement interval of , or less, arrive at the same time will be described.

In this case, the frequency difference/time difference converting means 31 and the simultaneously arriving signal frequency difference determining means 32 are used for reception. The above-mentioned simultaneously arriving multiple signals with close frequencies are distributed by the distributor 21 to the frequency difference/time difference conversion means 31, and are combined with the frequency sweep signal output from the sweep oscillator 23 by the mixer 22 to be frequency converted. This is a so-called chilb signal. Figure 2 (al) shows the human input signal waveform when the incoming signal is one wave, and Figure 2 (b) shows the chirp waveform of this signal. . . , ch, , '. The chirp signal distributed to each channel is passed through band filters 251 . . . , 2 having rectangular passband characteristics.
5. , pass through. Bandpass filter 250. ...25,
The passband is based on the signal distributed by the distributor 21 when an arbitrary incoming signal passes through the channel i filter (i is any integer from 1 to n) in the channel division receiver 9. The chirp signals formed in the above are selected so as to pass through the channel and i' bandpass filters in the frequency difference/time difference conversion means 31, respectively. Bandpass filter 253. ...
, 25fi are passed through pulse compression filters 261, . . . , 26. , and undergoes pulse compression processing, which is the same as in the case of a radar device, and the pulse compression filter 261 . ..., 26
, the operating band of the bandpass filters 25I, . . . , 25. l
The operating band is the same as that of In Fig. 2 (C1 shows the output signal waveform of the pulse compression filter, Fig. 10), the horizontal axis, that is, the time axis, means the frequency axis, and the position on the time axis, that is, the time, indicates the frequency. . This relationship is shown in Figure 2 (dl
The output of the pulse compression filter shown in FIG.・・・
, 277, and the amplifier 292 . ..., 297
After being amplified by the pulse counters 291, . . . , 29.
Added to 1. Pulse counter 291. ..., 29
7 is the number of compressed video pulses that are the amplifier output,
Counting is performed during one sweep period of the sweep oscillator 23. The count value is reset to O every time the sweep period ends. This count value is transmitted to the determination circuit 30, and the determination circuit 30 determines whether the count value of each channel is less than 1 or more than 2.8 Multiple signals that arrive simultaneously with close frequencies are not directly aligned on the time axis. At the same time, the amplifiers 281,...
In the 28fi output, there are multiple compressed video pulses with different time positions depending on the frequency, so
If the count value is 2 or more, it can be seen that there are multiple simultaneously arriving signals with close frequencies. When the count value is 2, the time interval measurement circuit 353. If the time interval between a plurality of compressed video pulses is measured by .

With the above operation, the frequency that could not be detected by the channel division receiver 9 using the filter bank 11 is changed to chl.
,...,ch,,filter 151. . . 15, the presence of a plurality of simultaneously arriving signals close to each other at a frequency array interval Fb or less and the frequency difference thereof can be detected simultaneously and easily.

In the above embodiment, the frequency difference/time difference converting means and the simultaneously arriving signal frequency difference determining means are provided for each channel over the entire receiving frequency band of the channel division receiving apparatus, but since these means are provided for each channel, The circuit scale becomes larger. A channel division receiving device according to another embodiment of the present invention is shown in FIG. It is a divisional receiving device.

In FIG. 3, 25 is a bandpass filter, 26 is a pulse compression filter, 27 is a detector, 28 is an amplifier, 33 is a timing generation circuit, 343. ..., 34, l is a gate circuit. The passband of the bandpass filter 25 is such that any incoming signal is
When passing through an arbitrary band filter among the band filters h, , , the chirp signal formed based on the signal distributed by the distributor 21 passes through the band filter 25 in the frequency difference time difference conversion means 31. chosen to pass. Further, the operating band of the pulse compression filter 26 is the same as that of the bandpass filter 25. Timing creation circuit 33
out of the compressed video pulse which is the output of the amplifier 28 shown in FIG. 4(a), the gate circuit 34. .

..., 34. In l, respectively ch h, ,...
Bandpass filter 151 .ch for each channel of h, .・・・
・, period B on the time axis corresponding to the passing frequency of 15° (
A gate signal (shown in FIG. 4 (C1)) is created to pass only the compressed video pulses present in the compressed video pulses present in the video pulses (shown in FIG. 4(b)). , that is, the inputs of the pulse counters 293, . . . , 29° are as shown in FIG. 4 (dl), for example.

With the above configuration, the frequency c that could not be detected by the channel division receiver 9 using the filter bank 11 is
h,...,ch,, filter 157. ...15
The existence of a plurality of simultaneously arriving signals close to each other at a frequency arrangement interval Fb of 7 or less and the frequency difference thereof can be detected using a detection means having a relatively small circuit scale. The detection operation and detection principle are the same as in the embodiment shown in FIG.

〔Effect of the invention〕

As described above, according to the receiving device according to the present invention, since the frequency difference time difference converting means and the simultaneously arriving signal frequency difference determining means are provided, a plurality of high frequency signals whose frequency intervals are equal to or less than the channel division frequency width arrive at the same time. In this case, the simultaneous arrival and the frequency difference can be easily detected.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing a receiving device according to an embodiment of the invention, FIG. 2 is a diagram showing waveforms of each part of the device in FIG. 1, and FIG. 3 is a configuration showing another embodiment of the invention. Block diagram; Figure 4 is a diagram showing waveforms of each part of the device in Figure 3;
FIG. 6 is a block diagram showing a conventional channel division receiver, and FIG. 6 is a diagram showing bandpass characteristics of a filter bank. In the figure, 21 is a distributor, 22 is a mixer, 23 is a sweep oscillator, 24 is a distributor, 258 . ..., 25 is a bandpass filter, 263. . . , 267 is a pulse compression filter, 271 . ..., 27° is a detector, 281, ...
, 287 are amplifiers, 291 . , 297 is a pulse counter, 30 is a determination circuit, 31 is a frequency difference time difference conversion circuit, 32 is simultaneous arrival signal frequency difference determination means, 353.・
..., 35o is a time interval measuring circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts. Figure 7 IF, IFJ- Figure

Claims (1)

[Claims] (1) In a receiving device that divides the receiving frequency band into multiple small continuous frequency bands for reception, when multiple high-frequency signals within the receiving frequency band and whose frequency interval is less than the channel dividing frequency width arrive at the same time. , a receiving device comprising a frequency difference/time difference converting means for converting a frequency difference between a plurality of simultaneously arriving signals into a time difference, and a simultaneously arriving signal frequency difference determining means for determining a frequency difference between the simultaneously arriving signals from the time difference. .