JP2001267971A - Frequency hopping signal searching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency hopping signal searching device that can confirm the presence of a frequency hopping wave among various space radio waves, detect a hopping rate and a frequency switching timing or the like. SOLUTION: The frequency hopping signal searching unit uses a micro scan reception section and a difference circuit employing a delay circuit to convert a signal received from an antenna into a signal on time base, analyzes the periodicity of a pulse train signal obtained thereby to detect the presence of a frequency hopping wave and a hopping rate and also a frequency switching timing or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency hopping signal detecting device for detecting a frequency hopping signal.

[0002]

2. Description of the Related Art FIG. 12 is a diagram showing a circuit configuration of a conventional device. In the conventional device, during the period from the antenna 1 to the output 18, the high-speed running receiver 11, the threshold comparator 12, the stimulus intensity adder 14, the stimulus intensity memory 15, the signal processor 16,
Are connected, and a threshold setting unit 13 for setting a comparison value to the threshold comparator 12, a controller 17 for controlling the high-speed running receiver 11, the threshold setting unit 13, and the signal processor 16
Are added.

Next, the operation will be described. Space radio waves are captured from the antenna 1 to the high-speed running receiver 3. The high-speed running receiver 11 runs the running band specified by the controller 17 for a short period of time equal to or less than half of one dwell time of the frequency hopping wave, and reduces the reception intensity of each frequency channel by one.
Output continuously for each channel. The reception intensity of each channel is compared with a threshold value by the threshold value comparison circuit 12, and the reception intensity is output only when the reception intensity is larger than a predetermined threshold value. In the impression intensity adder 14, the reception intensity obtained by one run is added and stored in the impression intensity memory 15. The above operations are repeated a specified number of times (N times),
By executing the N times, a change in the integrated reception intensity P (n), which is the sum of one reception run of each reception intensity P, is obtained. When this time is repeated at one fixed period, it is determined that the frequency hopping wave has been received, and the output signal from the signal processor 16 is output from the output 18.

[0004]

Since the conventional apparatus is configured as described above, when a plurality of frequency hopping waves are present at the same time, the change time of the integrated value of the integrated reception intensity is switched to the frequency hopping wave. It's shorter than the time and I can't find a hopping rate. In addition, when there are a large number of radio waves or when there is a radio wave with a large reception intensity, a change in the frequency hopping wave is small, so that a high-speed running receiver capable of detecting the reception intensity with high resolution is required. And so on.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and includes a method of determining the presence or absence of a frequency hopping wave in the presence of a plurality of frequency hopping waves and various types of spatial radio waves, detecting a hopping rate, and It is an object of the present invention to provide a frequency hopping wave detection device capable of detecting a switching point of frequency hopping.

[0006]

In order to solve the above-mentioned problem, an input signal is repeatedly scanned at a constant period at a high speed.
A chirp expanding section for converting this into a scanning signal expanded on the frequency axis, and outputting the signal converted to the scanning signal via a different delay line according to each frequency of the scanning signal, and outputting the signal on the time axis. A microscan receiver comprising a chirp compressor for converting the signal into a compressed signal; a signal having a delay time of one cycle of the scanning, the output of which is delayed from the microscan receiver; A difference extraction unit for extracting a difference from the output of the unit, and a pulse generation frequency of an output pulse train signal of the difference extraction unit is analyzed, and a pulse repetition period included in the output pulse train of the difference extraction unit is detected from the periodicity thereof. There is a pulse repetition period detector and a pulse train in which the frequency of occurrence of this periodic pulse is larger than a preset value The case, in which a frequency hopping signal detecting unit to detect this as frequency hopping signal exists in the received signal.

A hop rate detecting unit for detecting a hop rate of a frequency hopping signal included in a received signal with a repetition period when a pulse train signal whose frequency of occurrence of a periodic pulse train signal is larger than a preset value is present. It is provided with.

Further, a pulse train signal, which has been converted into a desired frequency hopping signal by the pulse repetition period detecting unit, is extracted from the pulse train signal output from the difference extracting unit, and a switching timing signal synchronized with the frequency switching timing of the frequency hopping signal is extracted. It is generated.

Also, a receiving section comprising a plurality of channel receivers provided corresponding to each frequency channel of the frequency hopping signal, a rising edge of an input signal to the receiving section is detected, converted into a pulse signal and output. A rising edge detector, a signal synthesizing unit for synthesizing an output signal of the rising edge detector for each frequency channel, and a pulse generation frequency of an output pulse train signal of the signal synthesizing unit are analyzed. A pulse repetition period detecting unit for detecting a contained pulse repetition period, and, when there is a pulse train in which the frequency of occurrence of this periodic pulse is larger than a preset value, detecting that a frequency hopping signal is present in the received signal. And a frequency hopping signal detection unit.

A hop-rate detecting section for detecting, as a hop rate of a frequency hopping signal included in a received signal, a repetition period when a pulse-train signal having a periodic pulse-train signal occurrence frequency greater than a preset value exists. The frequency hopping signal detecting device according to claim 4, comprising:

[0011] A pulse train signal, which has been converted into a desired frequency hopping signal by the pulse repetition cycle detecting unit, is extracted from the output pulse train signal of the signal synthesizing unit, and a switching timing signal synchronized with the frequency switching timing of the frequency hopping signal is extracted. It is generated.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, and 5.
A description will be given based on FIG. 6, and FIGS. 7 and 8. Note that, based on the configuration diagram shown in FIG. 1, some of the components are different between FIGS. 7 and 8. 1, 2, 4, 6, 7, and 8, 1 is an antenna, 2 is a microscan receiver, 3 is a one-scan delay circuit 31 and a subtraction circuit 32, each having a delay time equal to one scan. , A pulse repetition period detector,
Reference numeral 5 denotes a hopping signal detection unit, 6 denotes a hopping rate detection unit, and 7 denotes a switching timing signal generation unit. In the configuration diagram of the microscan receiver 2 shown in FIG.
21 is a chirp signal generator, 22 is a mixer, 23 is a dispersion delay circuit, and 24 is a logarithmic amplifier.

Next, the operation of the microscan receiver 2 will be described first. The input signal of the frequency popping wave (hereinafter, referred to as FH wave) shown in FIG. 3A is scanned by the mixer 22 so that the frequency increases with time at a period earlier than the duration of one chip of the FH wave. The signal from the chirp signal generator 21 is chirp-converted, and this chirp-converted signal is passed through a dispersion delay circuit 23 having a characteristic inverse to the frequency characteristic of the chirp signal generator 21 and having a delay time shorter with frequency. In this way, as shown in FIG. 3B, the input signal is output as a pulse-shaped compressed signal at a position on the time axis determined for each frequency. This compressed signal is output through the logarithmic amplifier 24 and guided to the difference extracting unit 3. The pulse signal input to the difference extraction unit 3 is guided to a one-scan delay circuit 31 and a subtraction circuit 32 having the same time length as the scanning cycle of the chirp signal generator 21. FIG. 3 (b)
Appear at the same position on the time axis within the time width of one scan time during the duration of one chip of the FH wave. When this is passed through the difference extracting unit 3, the pulse group appearing at the same position is differentiated from the signal one scan before, and as shown in FIG. 3 (c), the frequency of the FH wave is switched. Only the first pulse can be extracted.

The above is the case where one set of FH waves is input. Next, the case where two sets of FH waves are input will be described with reference to FIG. When two sets of FH waves shown in FIG. 5 (a) are input, a pulse train signal compressed at a position corresponding to the frequency of the FH wave at that time is obtained at the output of the microscan receiver 2, As a whole, two types of pulse train signals shown in FIG. 5B are obtained. This pulse train signal appears at the same position within the time width of one scan time during the duration of one chip of the FH wave. 5 is different from the signal before one scan,
As shown in (c), only the first pulse of the frequency switching of each FH wave can be extracted.

The pulse train for each FH wave obtained in this way is guided to the pulse repetition period detecting section 4 and its appearance frequency is analyzed to detect the pulse repetition period. In the case of the FH wave, a pulse train signal shown in FIGS. 3C and 5C is obtained every time the frequency is switched, and the pulse repetition cycle is FH.
It becomes the frequency switching cycle of the wave (hop rate of the FH wave). When the pulse repetition period is detected by such a method, the pulse train obtained by the FH wave has periodicity and has a high frequency of occurrence, and can be distinguished from other signals. FIG. 4D shows the case where one set of FH waves is used.
FIG. 6D shows the relationship between the periodicity and the occurrence frequency when there are two sets of FH waves. As can be seen from this figure, the pulse train obtained by the FH wave has a specific period and is generated at a high frequency, so that it can be distinguished from those generated by other signals. Reference numeral 5 denotes a hopping signal detection unit for detecting an FH wave by applying such a concept. FIG. 7 shows a hop rate detection unit that detects the hopping rate of the FH wave by applying the above concept.

The switching timing signal generator 7 in FIG. 8 generates a signal having desired FH wave switching timing information and uses it for various controls. That is, the pulse repetition period detection unit 4 specifies a desired FH wave from a large number of pulse signals, and selects a pulse train signal at the output of the difference extraction unit 3 generated by the FH wave. Obtain the desired FH wave switching timing information,
Based on this information, a pulse train signal of a required form can be generated.

Embodiment 2 FIG. Next, a second embodiment. Will be described. 9, 10, and 11 are configuration diagrams according to the second embodiment. The second embodiment is based on the configuration diagram shown in FIG. 9, and some components are different between FIGS. 10 and 11. 9, 10, and 11, those denoted by the same reference numerals as those denoted in FIG. 1, FIG. 7, or FIG. 8 indicate those having the same contents or functions. 8 is
Channel receiver 81 corresponding to each channel of FH wave
To 8n, 9 is a receiver for each channel.
This is a rise detection unit composed of rise detectors 91 to 9n provided for every 8n. This rising detector detects the rising of the input signal of the channel receiver and outputs it as a pulse signal. Reference numeral 10 denotes a signal combining unit that combines the pulse signals from the rising detectors 91 to 9n to generate a pulse train signal. In the configuration in this embodiment, the rising detector corresponding to the channel receiver that receives a new frequency to which the FH wave hops every time the FH wave hops detects this and outputs a pulse signal.
A pulse train similar to the output of the difference extracting unit 2 in the first embodiment is obtained from the output of the signal synthesizing unit 10.

Next, the operation will be described. FIG. 9 corresponds to FIG. 1 of the first embodiment, and a pulse train similar to the output of the difference extraction unit 2 in the first embodiment is obtained at the output of the signal combining unit 10 as described above. In response to this, the hopping signal is detected using the pulse repetition detection unit 4 and the hopping signal detection unit 5 in the same manner as in the case of FIG. 1 of the first embodiment. In the configuration shown in FIG. 10, the hop rate is detected by using the hop rate detection unit 6 in the same manner as in the case of FIG. 7 of the first embodiment. Further, in the configuration of FIG. 11, the switching timing signal is generated by using the switching timing signal generator 7 in the same manner as in the case of FIG. 8 of the first embodiment.

[0019]

As described above, in the frequency hopping signal detecting apparatus according to the present invention, a chirp expanding section for repeatedly scanning an input signal at a high speed with a constant period and converting the input signal into a scanning signal expanded on the frequency axis. And a chirp compression unit configured to output the signal converted to the scanning signal through a delay line having a delay time different according to each frequency of the scanning signal, and to convert the signal into a signal compressed on a time axis. A scan receiving unit;
A difference extracting unit that has a delay time of one cycle of the scanning and extracts a difference between a signal obtained by delaying the output of the microscan receiving unit and the output of the microscan receiving unit, and an output pulse train of the difference extracting unit A pulse repetition period detection unit that analyzes a pulse generation frequency of a signal and detects a pulse repetition period included in an output pulse train of the difference extraction unit from the generation frequency of the periodic pulse, and the periodicity is larger than a preset value. If there is a pulse train,
Since the frequency hopping signal is provided in the received signal and the frequency hopping signal detection unit for detecting the frequency hopping signal is provided, the FH wave can be reliably detected.

In addition, a hopping rate detecting unit is provided for detecting, as a hopping rate of a frequency hopping signal included in a received signal, a repetition period when a pulse train whose frequency of occurrence of a periodic pulse signal is larger than a preset value exists. Therefore, the hopping rate can be reliably detected.

A pulse sequence signal, which is determined as a desired frequency hopping signal by the pulse repetition period detecting unit, is extracted from the output pulse sequence signal of the difference extracting unit, and a switching timing signal synchronized with the frequency switching timing of the frequency hopping signal is generated. Thus, there is an effect that a signal synchronized with frequency hopping can be generated and used for control.

Also, a receiving section provided corresponding to each frequency channel of the frequency hopping signal, a rising detecting section for detecting a rising edge of an input signal to the receiving section, converting the signal into a pulse signal and outputting the pulse signal, Analyzing the pulse generation frequency of the output pulse train signal of the synthesis circuit and the synthesis circuit that synthesizes the output signal of the rise detection unit for each channel,
A pulse repetition period detection unit that detects a pulse repetition period included in the output signal of the rising detection unit based on the periodicity; and, when a pulse train in which the frequency of occurrence of the periodicity is larger than a predetermined value exists, the frequency of the received signal is Since a frequency hopping signal detection unit for detecting a hopping signal is provided if the hopping signal is present, there is an effect that the FH wave can be reliably detected.

Also, a hop rate detecting unit is provided which detects a pulse train whose frequency of occurrence of the periodic pulse signal is larger than a preset value is detected as a hop rate of a frequency hopping signal included in the received signal with the repetition period. Therefore, the hopping rate can be reliably detected.

Further, a pulse train signal, which has been converted into a desired frequency hopping signal by the pulse repetition period detecting unit, is extracted from the output pulse train signal of the signal synthesizing unit, and a switching timing signal synchronized with the frequency switching timing of the frequency hopping signal is extracted. Since the signal is generated, a signal synchronized with frequency hopping can be generated and used for control.

[Brief description of the drawings]

FIG. 1 is a configuration diagram according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a microscan receiver.

FIG. 3 is an explanatory diagram of a signal of each unit when one FH wave is used.

FIG. 4 is a diagram illustrating a relationship between a pulse repetition cycle and an occurrence frequency when one FH wave is used.

FIG. 5 is an explanatory diagram of a signal of each unit when two FH waves are used.

FIG. 6 is a diagram illustrating the relationship between the pulse repetition period and the frequency of occurrence when two FH waves are used.

FIG. 7 is a configuration diagram according to the first embodiment.

FIG. 8 is a configuration diagram according to the first embodiment.

FIG. 9 is a configuration diagram according to a second embodiment of the present invention.

FIG. 10 is a configuration diagram according to a second embodiment.

FIG. 11 is a configuration diagram according to a second embodiment.

FIG. 12 is a configuration diagram according to a conventional example.

[Explanation of symbols]

1 antenna, 2 microscan receiver, 21
Chirp signal generator, 22 mixer, 23 dispersion delay circuit, 24 logarithmic amplifier, 3 difference extractor, 4
Pulse repetition period detector, 5 hopping signal detector, 6 hop rate detector, 7 switching timing signal generator, 8 receiver, 81 to 8n channel receiver, 9 rising detector, 91 to 9n rising detector, 10 signals Synthetic unit.

Claims (6)

[Claims] 1. A chirp expanding section for repeatedly scanning a received signal at a predetermined constant cycle and converting the signal into a scanning signal expanded on a frequency axis, and a signal converted to the scanning signal, the delay time of which A micro-scan receiver comprising a chirp compressor for outputting via a different delay line according to each frequency of the scanning signal and converting the signal into a signal compressed on the time axis, and a delay time for one cycle of the scanning. A difference extraction unit for extracting a difference between a signal obtained by delaying the output signal of the microscan reception unit by the one-scan delay circuit and an output signal of the microscan reception unit, and a pulse of an output pulse train signal of the difference extraction unit A pulse for analyzing the occurrence frequency and detecting the pulse repetition period included in the output pulse train of the difference extraction unit from the periodicity thereof A repetition period detection unit, and a frequency hopping signal detection unit that detects the presence of a frequency hopping signal in a received signal when there is a pulse train in which the frequency of occurrence of the periodic pulse is greater than a preset value. Frequency hopping signal detecting device. 2. An output pulse train signal of a difference extraction unit,
A hop rate detection unit that detects a pulse train signal having a periodicity greater than a predetermined frequency and generates a hop rate of a frequency hopping signal included in a received signal with a repetition period of the pulse train signal. The frequency hopping signal detection device according to claim 1. 3. An output pulse train signal of a difference extraction unit,
A switching timing signal generating unit that extracts a periodic pulse train signal that has been set as a desired frequency hopping signal in the pulse repetition period detecting unit and generates a switching timing signal synchronized with the frequency switching timing of the frequency hopping signal. The frequency hopping signal detecting device according to claim 1 or 2, wherein: 4. A receiving section comprising a plurality of channel receivers provided corresponding to each frequency channel of the frequency hopping signal, and detecting rising edges of input signals to the plurality of channel receivers to generate a pulse signal. A rising detector provided for each channel receiver for conversion and output, a signal combining unit for combining output signals of the rising detector for each frequency channel, and a pulse generation frequency of an output pulse train signal of the signal combining unit is analyzed. A pulse repetition period detection unit that detects a pulse repetition period included in the output signal of the signal synthesis unit from the periodicity, and a pulse train in which the frequency of occurrence of the periodic pulse is larger than a preset value is present. And a frequency hopping signal detecting section for detecting that a frequency hopping signal is present in the received signal. A frequency hopping signal detection device characterized by the above-mentioned. 5. An output pulse train signal of a signal synthesizing section,
A hop rate detection unit for detecting a pulse train signal having a frequency of occurrence greater than a predetermined value and using the repetition period as a hop rate of a frequency hopping signal included in the received signal. 5. The frequency hopping signal detection device according to 4. 6. An output pulse train signal of a signal synthesizing unit.
A switching timing signal generating unit that extracts a periodic pulse train signal that has been set as a desired frequency hopping signal in the pulse repetition period detecting unit and generates a switching timing signal synchronized with the frequency switching timing of the frequency hopping signal. The frequency hopping signal detection device according to claim 4 or claim 5, wherein