JP3182454B2 - Variable period correlation type detection device and variable period correlation type signal detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correlation detection type detection device for obtaining a required detection signal by correlating using a promised waveform at the time of transmission, and to detect a required signal from a received signal by a similar configuration. The present invention relates to a correlation type signal detection device.

[0002]

2. Description of the Related Art There are a reflection type detection device and a transmission type detection device in this type of detection device, and the reflection type detection device includes a land condition, a ship navigation condition, a relative distance condition and the like by a reflected wave of an electromagnetic wave. Underwater objects, airborne objects, and relatives are reflected by sound waves or ultrasonic waves, such as radars for ships that detect objects, underground surveys that detect conditions of buried objects under the ground surface, changes in strata, and relative distances. There are fish finder and sonar etc. that detect the distance situation, etc., and as the transmission type detection device, the buried object situation and the stratum change situation etc. in the underground route between the required points by the transmitted wave (also called the passing wave) of the electromagnetic wave There are transmission / reception opposed detection radars and borehole radars that detect by transmitted waves, and transmission / reception opposed detection sonars that detect underwater and airborne objects by sound waves and ultrasonic waves.

In this type of detection device, a device provided with a correlation function in order to increase the detection capability, that is, as a correlation detection type detection device, a plurality of reception signals obtained in each detection cycle are superimposed. A configuration that takes a correlation is used.

[0004] This configuration is based on the signals R1, R2, R3 shown in FIG.
By superimposing a plurality of reception signals of each detection period T obtained by transmitting a single pulse transmission signal X1 and performing a logical sum or an average as shown in FIG. In this configuration, the received signals S1 and S2 that are commonly present at the same phase point of each detection cycle T are detected as detection signals.

[0005] In addition, as a device provided with a correlation function, for example, a communication signal transmitted from a communication device or a monitoring device, or an information signal in which a monitoring signal in a facility is multiplexed is repeated at a required period. A correlation signal detection device configured to obtain a required detection signal by correlating the signal with a correlation signal having a promised waveform at each time of the cycle, the signal being a signal including a waveform signal. Can be considered.

In order to make such a correlation effective, the transmission waveform may be a stepped amplitude form in which a specific promise is made for amplitude change, frequency change, phase change, number of pulses, pulse interval, etc., an equal waveform repetition form, or the like. In the former, the step-shaped amplitude type, in which the amplitude is changed stepwise, the latter, in which the waveform is repetitive, the half-sinusoidal pulse or the rectangular pulse is applied in the positive direction. 7 or repeated by a predetermined number in both the positive and negative directions. The simplest waveform is a single one as shown in FIG.
Cycle (referred to as monocycle in the present invention),
There is a unipolar pulse corresponding to a single サ イ ク ル cycle as shown in FIG.

The reason why the correlation function is provided in the detection device is mainly that a detection signal having a good S / N is obtained by removing interference interference and environmental noise from a weak reception signal having a low S / N, and obtaining a detection signal having a good S / N. Even if the power peak value is small, the detection distance can be increased. Similarly, even if the transmission signal has a small power peak value, the function using the pulse compression technique is a function that can increase the detection distance. There is a configuration in which pulse compression is performed using waveforms such as stepped frequency modulation format, linear frequency modulation format, code phase modulation format, and code carrier modulation format. Technology (2) ".

Here, the step frequency modulation type is
As shown in the waveform (a) of FIG. 7, the frequency is changed as f1, f2, f3, f4, f5 for each small unit time Ta.
As shown in the waveform (a) of FIG.

In the code phase modulation type, as shown in a waveform (c) of FIG. 7, a signal of each cycle having a constant cycle Tb is set as a pulse signal of one unit. A code whose phase starts from the 0 ° position is set to “+” and a signal whose phase starts from the 180 ° position is set to “−”, and the code is modulated by the code carrier modulation type. , The frequencies f1 to f5 of the signal in the stepped frequency modulation type are changed to carrier signals of the same frequency, and the carrier wave in each unit time Ta is changed to 1 in the code phase modulation type of the waveform (c) in FIG.
Each unit pulse is encoded in the same manner as the unit pulse.

It is needless to say that the waveforms in each of these formats can be used as promised waveforms for the above-mentioned correlation function. In the present invention, the promised waveform is
It indicates a waveform in each of these formats.

[0011]

In the above-described correlation configuration in which a plurality of periods are superimposed and a logical sum or an average is obtained, as shown in FIG. However, if the signal exists at the same location, that is, at the same phase point, there is a disadvantage that the signal is detected regardless of the noise signal or the interference signal.

For this reason, there is a problem that provision of a simple and inexpensive configuration free of such inconveniences is desired.

[0013]

According to the present invention, there is provided a reflected wave obtained by transmitting a transmission signal having a bundled waveform having a time length shorter than the period repeated at a required period as described above. Or in a correlation detection type detection device that obtains a required detection signal by correlating a received signal of a transmitted wave with a promised waveform, a variable period means for obtaining a variable period by sequentially extending the above period by a small amount of time each time, A fixed-delay transmission means for performing the above-mentioned transmission at each time when a predetermined fixed delay amount is added to each variable period, a variable-period correlation signal means for obtaining the signal of the above-mentioned promised waveform as a correlation signal for each variable period, Multiplication means for obtaining a detection signal based on a multiplication signal obtained by multiplying the received signal as a correlated signal by the above-described correlation signal, or the above-described cycle is sequentially performed by a small amount of time each time. Short A variable period means for obtaining the variable period, a variable period transmitting means for performing the transmission according to the variable period, and correlating the signal of the promised waveform each time a predetermined fixed delay is added to each variable period. The above problem is solved by a configuration in which fixed delay correlation signal means obtained as a signal and multiplication means for obtaining a detection signal based on a multiplication signal obtained by multiplying the reception signal by the above correlation signal as a correlated signal are provided. This cycle to solve and repeat at the required cycle
The above-mentioned problem is solved by providing a similar configuration in a correlation-type signal detection apparatus that obtains a required detection signal by correlating a reception signal including a signal having a promised waveform with a time length shorter than a period with a promised waveform. It is something that can be solved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment will be described below with reference to FIG. The embodiment of FIG. 1 relates to an underground exploration radar for exploring the underground from the air, as shown in FIG.
The waveform of a cycle, that is, the waveform of a monocycle is correlated as the simplest promised waveform, and the signals of each section are shown in FIG. Note that FIG.
And the waveform of the monocycle with the time length TPX is
Promised waveform with a shorter time length than this cycle
ing.

The variable period circuit 1X converts a variable period signal 1XA of a pulse signal having a variable period TE, which is sequentially extended by a small amount of time Δt, into the initial period T, that is, the initial period T each time, into the fixed delay circuit 12 And a correlation signal circuit 13.

The variable period circuit 1X is, for example, a pulse generating circuit combining a clock circuit of Δt and a counting circuit. When T = Δt × n, n is a fixed amount.
n + 1, n + 2, n + 3... n + r, n + (r + 1),
n + (r + 2) ... n + (n-2), n + (n-1),
By counting up to n + n and obtaining each cycle, T ~
A pulse signal of a variable period that is sequentially extended by a small amount of time Δt within a period of (T + Δt × n) is generated, where Δt is a transmission waveform circuit 21 and a correlation signal circuit 13 described later. , The transmission signal 2X
The time length TPX between A and the correlation signal 13XA is selected to be 1 / m, for example, 1/10.

The correlation signal circuit 13X includes a variable period signal 1X.
A circuit for generating a signal having a promised waveform of a monocycle waveform having a time length TPX for each A as a correlation signal 13XA. The generated correlation signal 13XA is supplied to one multiplication input of a multiplication circuit 11.

The fixed delay line 12 is a circuit for delaying the variable period signal 1XA by a predetermined fixed delay amount FD.
This is a delay circuit including a monostable multivibrator, and applies a delayed fixed delay signal 12XA to the transmission circuit 2.

In the case of the first embodiment shown in FIG.
Is set to a fixed delay amount FD corresponding to one period of the initial period T. Therefore, the fixed delay signal 12XA given to the transmission circuit 2 is always a promised waveform delayed by the same fixed delay amount FD as the initial period T from the time of the variable period signal 1XA for each variable period TE. Appears as a cycle signal.

The correlation signal 13XA applied to one input of the multiplication circuit 11 appears as a promised waveform, that is, a monocycle signal for each variable period TE.

In other words, the transmission signal 2XA is supplied to the transmission antenna 3 with a signal of a promised waveform delayed by the same fixed delay amount FD as the initial period T while sequentially extending the detection period by Δt each time. Similarly, the received signal 10XA (noise signal is omitted) obtained from the signal 9XA appears as a signal delayed by Δt each time.
The correlation signal 13XA is always delayed by the initial period T.

Therefore, the promised waveform signal given to one input side of the multiplication circuit 11, that is, the correlation signal 13XA
From the viewpoint, the received signal 10XA given as the correlated signal to the other multiplication input becomes a signal delayed by a time corresponding to the initial period T for each variable period TE, so that the correlation signal after the second time of the variable period TE The signal 13XA is delayed first, and the received signal 10XA is received at a time that is sequentially carried up by Δt at each time of the variable period TE. And signals 10a and 1 from underground objects 7A, 7B and 7C
0b and 10c appear at times sequentially advanced by Δt.

For this reason, the multiplication signal 11XA is obtained by shifting the correlation signal 13XA backward by the variable period TE, that is, by Δt for each detection period with respect to the reception signal 10XA.
Since it is obtained as a signal having an amplitude value obtained by multiplying the amplitude value of each signal, the multiplication signal 11XA, the integration signal 14XA,
As the detection signal 15XA, a detection signal obtained by performing the correlation detection processing and the pulse compression processing is obtained.

The variable period TE is the first fixed period T
When the cycle becomes twice as large as the above, the correlation detection processing and the pulse compression processing for the detection distance range corresponding to the first fixed cycle T are completed.

In the first embodiment shown in FIG.
Is provided between the variable period circuit 1X and the transmission circuit 2 so as to perform a fixed delay. However, the fixed delay circuit 12 is removed, and the fixed delay circuit 12 is disposed between the reception antenna 9 and the amplification circuit 10. Alternatively, even if the reception signal 9XA or the reception signal 10XA is provided with a fixed delay by being provided between the amplification circuit 10 and the multiplication circuit 11, the correlation signal, that is, the reception signal 10XA given to the multiplication circuit 11 is obtained. The time relationship between the correlation signal 13XA and the correlation signal 13XA is the same as that in the embodiment of FIG. 1, and a detection signal obtained by performing the same correlation detection processing and pulse compression processing can be obtained.

In the case of a detection device for performing underground exploration using transmitted waves as shown in FIG.
The correlation signal 1 is provided by the variable period circuit 1X, the correlation signal circuit 13, and the fixed delay line 12 provided in any of the display circuit units 70.
3XA and the fixed delay signal 12XA are obtained, and the multiplication signal 11XA is obtained by the multiplication circuit 11 provided in the reception side circuit unit 60 or the control / display unit 70. Is obtained, or the fixed delay line 12 is connected to the receiving antenna 9 and the receiving side circuit unit 6 in the same configuration.
0, or between the receiving circuit 10 and the multiplying circuit 11 provided in the receiving circuit unit 60 or the control / display circuit unit 70, thereby achieving the same correlation detection processing. A detection signal that has been subjected to the pulse compression processing can be obtained.

Further, in the case of the above-mentioned correlation type signal detector, the correlated signal including the signal of the promised waveform is converted into the correlated signal having the above-mentioned variable period TE, and is given to the above-mentioned fixed delay circuit 12 to be fixed. By providing the delayed delayed correlated signal and the correlation signal with the promised waveform having the variable period TE to the multiplication circuit 11 to obtain a signal corresponding to the multiplication signal 11XA, the correlation detection processing and the pulse compression processing can be performed. Can be obtained.

Next, a description will be given of a second embodiment in which the variable period TE of the variable period circuit 1X in the above-described first embodiment is sequentially shortened by a small amount of time Δt with reference to FIG.

In the case of the second embodiment shown in FIG. 3, the variable period circuit 1X is replaced with a variable period circuit 1Y for generating a shortened change type variable period signal 1YA, as compared with the first embodiment shown in FIG. While providing the periodic signal 1YA to the transmission circuit 2,
The fixed delay circuit 12 includes a variable period circuit 1Y and a correlation signal circuit 1
3 is different from that of the first embodiment shown in FIG.

The variable period signal 1YA has an initial period TS of T + Δt × n as shown in FIG. 4, and a change in the portion of Δt × n starts from Δt × n, and t × (n−1) , Δt × (n−
2), Δt × (n−3)..., Which gradually reduces and shortens the variable period TE. Further, the fixed delay amount FD of the fixed delay circuit 12 is set to T + Δt which is the same as the initial period TS.
× n.

Therefore, the transmission signal 2YA output from the transmission circuit 2 and the reception signal 1YA output from the reception circuit 10
0YA and the correlation signal 13 output from the correlation signal circuit 13
The relative time relationship with YA is shown in FIG.
In this case, the time relationship is as if the fixed delay time FD was simply changed to T + Δt × n.
1 multiplication signal 11YA, integration signal 14Y of integration circuit 14
A, since the detection signal 15YA of the sample holding circuit 15 has a similar time relationship, when T = △ t × n, a signal similar to the detection signal 15XA in FIG. 2 is obtained as the detection signal 15YA. become.

Further, the same correlation detection configuration as that of the second embodiment is used in the case of the above-described configuration based on the transmission / reception opposite detection, or
It goes without saying that the present invention can be applied to the above-described correlation type signal detection device.

[Modified Implementation] The present invention can be implemented with the following modifications. (1) The promised waveform is changed in amplitude, frequency, phase, pulse number, pulse interval, etc. as described in the section of the prior art. Waveforms with specific promises, such as staircase amplitude format / equal waveform repetition format, or staircase frequency modulation format / linear frequency modulation format / code phase modulation format / code carrier modulation format And the like, using any of the waveforms.

(2) A pulse wave obtained by modulating a signal of a promised waveform into a single high-frequency rectangular wave used in a general radar or fish finder, that is, an f1 portion of the waveform of FIG. Only the waveform is configured.

(3) The initial period T of the variable period TE and the fixed delay amount FD of the fixed delay circuit 12 in the first embodiment of FIG.
Is set to N × T, which is a multiple of N times, to perform the same correlation detection processing and pulse compression processing as in the embodiment of FIG.

(4) T + Δt × n of the initial period TS of the variable period TE and the fixed delay amount FD in the second embodiment of FIG. 3 is N × T + Δt × The configuration is such that correlation detection processing and pulse compression processing similar to those in the embodiment of FIG.

(5) Instead of the initial period T of the variable period TE in the first embodiment of FIG. 1, an amount of time obtained by adding an arbitrary amount of time T or less to the initial period T, or any amount of time equal to or less than T. By setting the amount of time as the initial period, a so-called detection range shift is performed, and a correlation detection process is performed from a time point corresponding to the target detection target, for example, the underground buried object 7B. The detection signal 15XA for the underground objects 7B and 7C is configured to be obtained.

(6) The same operation as the shift of the detection range in (5) above, except that the portion of T or Δt × n in the initial period TS in the second embodiment of FIG. Is performed.

(7) Fixed delay amount FD of fixed delay circuit 12
Is set to an initial period T or TS and an arbitrary amount of time equal to or less than T or Δt × n, or a delay amount obtained by adding an arbitrary amount of time equal to or less than T or Δt × n, for example, as shown in FIG. By setting a fixed delay amount corresponding to the delay amount of T × 0.6, a so-called shift of the detection range is performed, and the correlation is started from the time corresponding to the target detection target, for example, the underground buried object 7B. For example, the detection signal 15XA for the underground objects 7B and 7C is obtained by performing the detection processing.

(8) Correlation signal 13 given to multiplication circuit 11
The XA waveform is changed to a waveform close to a model that is deformed while the promised waveform on the transmission side passes through the path of the transmission circuit 2, the transmission antenna 3, the transmission electromagnetic wave 4, the underground, the reflected electromagnetic wave 8, and the reception antenna 9. For the purpose, a circuit corresponding to the waveform, for example, a combination of a resonance circuit having a low Q and a phase shift circuit is interposed in the correlation signal circuit 13 or between the correlation circuit 13 and the multiplication circuit 11.

(9) The integration circuit 14 is an operation type integration circuit, and the sampling and holding time of the sample holding circuit 15 is performed at each time of the variable period signal 1XA or 1YA. In this case, it is needless to say that the operation needs to be reset after sampling.

(10) In the configuration of the above (9), the digital value obtained by A / D conversion of the amplitude value obtained at each sampling time is stored in a storage circuit such as a memory or a shift register at an address or a shift at each sampling time. Are stored in the next order, and the stored contents are obtained based on a digital value read out by a clock at a predetermined constant speed, so that the detection signal 15XA or 15YA is obtained.
XA or 15YA waveform distortion can be corrected. When the detection signal or the detection signal is obtained in the reverse time series, the reading of the stored contents is performed in the reverse order to obtain a signal in a normal time series.

(11) The integration signal 14 and the sample holding circuit 15 are eliminated, and the multiplication signal 1 is output by the low-pass filtering circuit.
The detection signal 1 is obtained by filtering 1XA or 11YA.
5XA or 15YA is obtained. In this case, the variable period TE
Corresponding to the initial period T, that is, (1 / T) H
It is desirable to constitute a filtering circuit that passes a frequency of about z or less.

(12) The amount of the small time Δt is configured in another analog form, for example, the time to the clip level point of the rising or falling ramp is made by changing the unit clip level.

(13) Form of Promised Waveform and Small Time △
The quantity of t, or either, is constituted by a signal in digital form, for example a serial pulse signal or a parallel pulse representing a binary value.

(14) Form of Promised Waveform and Small Time △
An amount of t or any one of them is converted into an analog signal and converted into a digital signal to perform correlation.

(15) Form of Promised Waveform and Small Time △
The amount of t or any one of them is converted into a signal in a digital form and converted into a signal in an analog form to perform correlation.

(16) Received signal 10XA or 10Y
A, the correlation signal 13XA or 13YA is A / D converted and digitized, and the variable period circuit 1X or 1
Y, multiplication circuit 11, integration circuit 14, sample holding circuit 1
Processing such as 5 is performed by a digital computer, for example, a microcomputer.

(17) The reception signal 10XA or 10YA input to the multiplication circuit 11 and the correlation signal 13XA or 1
An adjustment circuit, such as a variable attenuation circuit, for variably adjusting the amplitude and ensuring the multiplication function is provided in both or any one of the 3YA circuits.

(17) Correlation signal 13XA or 13YA
Is a signal having a low frequency component, the multiplication circuit 11 is configured by a combination of operational amplifier circuits, for example, a multiplication IC or the like.

[0051]

According to the present invention, a received signal including a promised waveform is used as a correlated signal, and a promised waveform shifted sequentially by a small amount of time at each time of a cycle in which the received signal is obtained is multiplied as a correlation signal. Based on the obtained signal, a correlation detection process and a pulse compression process are performed to obtain a target detection signal or correlation detection signal. Therefore, the detection signal or the correlation detection signal having a high S / N ratio and high accuracy is obtained. There is such a feature that the obtained one can be provided by a simple configuration in which only a variable period circuit and a fixed delay circuit are provided.

[Brief description of the drawings]

 The figure shows an embodiment, and the contents of each figure are as follows.

FIG. 1 is a block diagram of a first embodiment of the present invention;

FIG. 2 is an operation waveform diagram of a main part of the first embodiment of the present invention.

FIG. 3 is a block diagram showing a second embodiment of the present invention;

FIG. 4 is an operation waveform diagram of a main part according to a second embodiment of the present invention;

FIG. 5 is an operation waveform diagram of a main part of a modified embodiment of the present invention.

FIG. 6 is a block diagram of a conventional technology.

FIG. 7 is a signal waveform diagram of a main part of a conventional technique.

FIG. 8 is a signal waveform diagram of a conventional technique.

[Explanation of symbols]

 1X detection period circuit 1XA detection period signal 1Y detection period circuit 1YA detection period signal 2 transmission circuit 21 transmission waveform circuit 22 power amplification circuit 2XA transmission signal 2YA transmission signal 3 transmission antenna 4 transmission electromagnetic wave 5 ground surface 6 underground 7A, 7B, 7C Underground object 8 Reflected electromagnetic wave 9 Receiving antenna 9XA Received signal 9YA Received signal 10 Amplifier circuit 10XA Received signal 10YA Received signal 11 Multiplication circuit 11XA Multiplied signal 11YA Multiplied signal 12 Variable delay circuit 12XA Delayed signal 12YA Delayed signal 13 Correlation signal 13XA correlation signal 13YA correlation signal 14 integration circuit 14XA integration signal 14YA integration signal 15 low-pass filtering circuit 15XA detection signal 15YA detection signal 16 display circuit 50 transmission side circuit unit 60 reception side circuit unit 70 control / display circuit unit 100 underground exploration Radar

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 5-240943 (JP, A) JP 5-288844 (JP, A) JP 5-288834 (JP, A) JP 2- 165086 (JP, A) JP-A-2-27285 (JP, A) JP-A-3-142392 (JP, A) JP-A-2-44277 (JP, A) JP-A 1-282490 (JP, A) JP-A-1-280279 (JP, A) JP-A-63-174082 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S ⁷ /00-7/42 G01S 13/00 -13/95

Claims (8)

(57) [Claims] 1. A short than the cycle repeats at a required period
A correlation-type detection device that obtains a required detection signal by correlating a reception signal of a reflected wave or a transmitted wave obtained by transmitting a transmission signal having a promised waveform of a long time with the promised waveform, Variable period means for obtaining a variable period sequentially extended by a small amount of time each time; fixed delay transmission means for performing transmission at each time when a predetermined fixed delay amount is added to each variable period; each of said variable periods Variable period correlation signal means for obtaining the signal of the promised waveform as a correlation signal every time, and multiplication means for obtaining the detection signal based on a multiplication signal obtained by multiplying the correlation signal with the reception signal as a signal to be correlated. A variable period correlation type detection device, comprising: 2. A cycle shorter than the cycle repeated at a required cycle.
A correlation-type detection device that obtains a required detection signal by correlating a reception signal of a reflected wave or a transmitted wave obtained by transmitting a transmission signal having a promised waveform of a long time with the promised waveform, A variable period means for obtaining a variable period sequentially reduced by a small amount of time each time; a variable period transmitting means for performing the transmission according to the variable period; and each time a predetermined fixed delay amount is added to each of the variable periods. Fixed delay correlation signal means for obtaining the signal of the promised waveform as a correlation signal; and multiplication means for obtaining the detection signal based on a multiplication signal obtained by multiplying the correlation signal with the reception signal as a signal to be correlated. A variable period correlation type detection device characterized by the above-mentioned. 3. A process according to claim 1 or請 characterized by including the multiplication means for performing an analog value the hanging calculated
The correlation detection type detection device according to claim 2. 4. The method of claim 1, characterized in that it comprises the multiplication means for performing the digital value of the hanging calculation or
The variable period correlation type detection device according to claim 2 . 5. A cycle shorter than the cycle repeated at a required cycle.
A correlated signal detection device that correlates a received signal including a signal having a promised waveform of a long time with the promised waveform to obtain a required detection signal, wherein the cycle is sequentially reduced by a small amount of time each time. Variable period means for obtaining an expanded variable period; fixed delay receiving means for obtaining the received signal having a start point of a period at which a predetermined fixed delay amount is added to each of the variable periods; and Variable period correlation signal means for obtaining a signal of a promised waveform as a correlation signal; and multiplication means for obtaining the detection signal based on a multiplication signal obtained by multiplying the reception signal as a signal to be correlated with the correlation signal. A variable period correlation type signal detection device characterized by the above-mentioned. 6. A cycle shorter than the cycle repeated at a required cycle.
A correlated signal detection device that correlates a received signal including a signal having a promised waveform of a long time with the promised waveform to obtain a required detection signal, wherein the cycle is sequentially reduced by a small amount of time each time. Variable period means for obtaining a shortened variable period; variable period reception signal means for obtaining the received signal having the variable period; and a signal of the promised waveform each time a predetermined fixed delay is added to each of the variable periods. And a multiplying means for obtaining the detection signal based on a multiplied signal obtained by multiplying the received signal as a correlated signal by multiplying the correlation signal by the received signal. Variable period correlation type signal detection device. 7. The method of claim 5 or請 characterized by including the multiplication means for performing an analog value the hanging calculated
The variable period correlation type signal detection device according to claim 6. 8. The method of claim 5 or, characterized in that it comprises the multiplication means for performing the digital value of the hanging calculated
The variable period correlation type signal detection device according to claim 6 .