SU1406609A1 - Correlation meter - Google Patents

Abstract

The invention relates to automation and radio engineering, is intended to measure the complex function of the mutual correlation of weak radio signals and can be used in radio astronomy, in studying random vibrations in distributed oscillatory systems, etc. The invention makes it possible to expand the class of problems to be solved by separating the quadrature components and the module of the complex cross-correlation function. The functions of mutual correlation of intensities and to expand the functionality by normalizing the output parameters. Introduction to the correlator phase shifter, low frequency filter, phase detector, quadrature phase shifter, synchronous detector, two integrators, two mixers, an adder, an amplitude detector, three bandpass amplifiers, as well as three quadrants, three additional intermediate frequency amplifiers and an additional band amplifier and mixer It does not identify quadrature components and the modulus of the complex cross-correlation function and the cross-correlation intensity functions; VAVO Wuxi divisor with adjustable gain factor, the two additional low-pass filters, two synchronous detectors and the two amplitude detectors allows normalized output parameters. 3 з.п, ф-л, 4 Il. with (L

Description

Odd

The invention relates to computing, is intended to measure the complex function of the mutual correlation of weak radio signals and can be used in radio astronomy, in the study of random vibrations in distributed oscillatory systems, etc.

The aim of the invention is to expand the class of tasks solved by allocating quadrature components and a module of a complex cross-correlation function, a function of mutual correlation of intensities, and an increase in functionality due to the normalization of output parameters.

Fig. 1-A shows a correlometer schematically.

The correlometer (FIG. 1) contains receiving channels 1 and 2. The receiving channels include a mixer 3, an intermediate frequency amplifier A, the local oscillator 5 and a mixer 6, an intermediate frequency amplifier 7, the local oscillator 8c. The correlometer also contains a mixer 9, a bandpass amplifier 10, a phase shifter 11, quadrature phase shifter 12, multiplier 13, band amplifier 1A, synchronous detectors 15 and 16, integrators 17 and 18, mixers 19 and 20, band amplifiers 2 and 22, adder 23, band amplifier 24, amplitude detector 25, phase detector 26 and filter 27 low frequencies.

The correlometer of FIG. 2 compared to the correlometer of FIG. Further comprises a quad 28, an intermediate frequency amplifier 29, a quad 30, an intermediate frequency amplifier 31, a quad 32, and a band amplifier 33.

The correlometer of FIG. 3 as compared with the correlometer of FIG. L further comprises a quadr 28, an intermediate frequency amplifier 29, a quad 30, an intermediate frequency amplifier 31, a bandpass amplifier 34 and a 35 ”mixer.

In the correlometer of FIG. 4, as compared with the correlometer of FIG. 1, an amplifier 36 with adjustable gain, amplitude detectors 37 and 38, synchronous detectors 39 and AO, and low-frequency filters 41 and 42 are additionally introduced.

The local oscillators 5 and B are tuned to the frequencies f, f, respectively.

1 f-2 fo-Fj,

where fg is the central part of the spectrum

input signals;

F RL, respectively, detuning frequencies of the local oscillators 5 and 8 from the frequency f (|.

Center frequencies f, f bandwidths of amplifiers 4 and 7

fj about 1 f about 1

Center frequencies fj, f bandwidths of amplifiers 29 and 31

f 2f j; f 2f ,. Center frequency of the pro-amp 10 amplifier band.

F IF, -.

5 o

Q

g

0

Center bandwidth of amplifiers 33 and 34

f7 2F.

In the correlometer of FIG. 2, the central frequency of the passband of the amplifiers 14, 21, 22 and 24 is 2F. In the correlometer of FIG. 3, the central frequency of the passband of the amplifiers 14, 21, 22 and 24 is equal to F. Quadrature phase detector 12 is made frequency-sensitive heterodyne 5 made tunable in frequency.

The correlometer works as follows.

The inputs of the receiving channels 1 and 2 signals

V, (t) A, (t) cos G + cf, (t) -, V, (t) A (t) cos + t / 5 (t),

where A, (t), A (t) are the amplitudes of the signals at the inputs of the receiving channels; fg is the central frequency of the spectra of the signals at the inputs of the receiving channels 1 and 2;

H (t), Cf (t) - phase signals at the inputs of the receiving channels 1 and 2

Mixers 3 and 6 and local oscillators 5 and 8 convert the corresponding input signals into intermediate frequency signals.

fo - ffJ F

ffl g

where f I, f are the frequencies of the signals of the local oscillators 5 and 8, respectively.

After amplification in amplifiers 4 and 7 of the intermediate frequency, the signals of the frequencies F, Fj are fed to the inputs of the multiplier 13, which selects the signal at the difference frequency

IF, - F, i If, -

amplitudes --A, (t) A (t).

This signal is amplified by a bandpass amplifier A and is fed to the information inputs of the synchronous detectors 15 and 16. The reference inputs of the synchronous detectors 15 and 16 receive reference signals, which are formed in the following way.

The mixer 9 converts the signals of the local oscillators 5 and 8 into the difference frequency signal;

F I F, -.

After the bandwidth amplifier 10 cig

The difference frequency F is fed to the input of the phase shifter 11, which introduces a phase shift into this signal. This ensures the balancing of the signals from the local oscillators 5 and B in phase

The output signal of the tunable phase shifter 11 is fed to the reference input of the synchronous detector 15 and to the input of the quadrature phase of the rotator .12, the output signal of which is the reference for the synchronous detector 16.

Synchronous detectors 15 and 16 and integrators 17 and 18 carry out you

division of quadrature components of the complex function of mutual correlation of signals. In this case, the signals on the first and second outputs of the correlometer have

view:

Ui (t) A / t)) c. (T) Uj (t) A, (t) -Ai (t), (t) (t) -u,

five

0

five

about

five

d

g

where), Aj (t) is the amplitude of the signals at the inputs of the receiving channels 1 and 2 ;,

I / (t), t /, (t) -phases of signals at the inputs of receiving channels 1 and 2; I is the time constant of integrators 17 and 18;

/ c is the phase shift introduced by the phase shifter 1 1.

Signals that carry information about the quadrature components of the complex cross-correlation function from the outputs of the integrators 17 and 18 are fed to the inputs of the corresponding mixers 19 and 20. The reference input of the mixer 19 receives a signal from the output of the phase shifter 11, and the reference input of the mixer 20 receives a signal from the output of the quadratures - phase shifter 12; Mixers 19 and 20 provide the transfer of the spectrum of low-frequency signals carrying information about the quadrature components of the complex cross-correlation function to the frequency

F | F ,.

The band amplifiers 21 and 22 provide amplification of the signal at the difference frequency F.

The adder 23 performs. summing the output signals of the bandpass amplifiers 21 and 22. As a result, the output of the adder 23 is a difference frequency signal F, This signal is amplified by a bandpass amplifier. 24 and detected by the amplitude detector 2Т, carries information about the module of the complex mutual correlation function of the input signals.

U (t) - A, (t) -A (t)

The frequency signals F from the outputs of the phase shifter 11 and the quadrature phase shifter 12 are fed to the inputs of the phase detector 26, the output signal of which is proportional to the deviation flF of the different frequency F from the nominal frequency F of the setting of the quadrature phase shifter 12, goes through the filter 27 to the control input of the local oscillator 5 The frequency of the local oscillator 5 is changed in such a way that the difference frequency of the signal from the output of the mixer 9 is given

to the frequency F of the setting of the frequency-sensitive quadrature phase shifter 12. This ensures the stabilization of the difference frequency of the local oscillators 5 and 8, as well as the orthogonality condition of the quadrature components of the complex cross-correlation function.

Quad 32, which converts a signal of frequency F to a signal of frequency 2F. The frequency signal 2F, amplified by a bandpass amplifier 33, is fed to the input of the phase shifter 11, which introduces a phase shift to this signal and (. The output signal of the phase shifter 11 is fed to the synchronous reference input

The correlometer in fig2 works on the detector detector 15 and on the quadrature input

blowing way. Mixers 3 and 6 and the local oscillators 5 and 8 convert the corresponding input signals into intermediate signals.

frequencies

fo

Where

- center frequency spectrum.

F

ditch signals at the inputs of receiving channels 1 and 2; the frequency of the signals, respectively, the local oscillators 5 and 8;

the frequency of the detuning of the corresponding-25 of the local oscillators 5 and 8 from the frequency f ..

15

20

These signals are amplified by the corresponding amplifiers 4 and 7 of the intermediate frequency and are fed to the inputs of the quadrs 28 and 30. The quadratures 28 and 30 convert the input signals.

frequency signals F doubled

1 frequency 2 F

F, in

signals

, and 2 F, which are then amplified by the corresponding amplifiers 29 and 31 of the intermediate frequency and fed to the inputs of the multiplier 13o. The multiplier 13 performs the selection of the difference frequency signal equal to

2F

2 / F ,, g,

the amplitudes of / - A (t) -A (t).

This signal is amplified by a band-pass amplifier 14 and fed to the signal inputs of the synchronous detectors 15 and 16. Signals input to the reference inputs of the synchronous detectors 15 and 16 are formed as follows. I

The mixer 9 converts the signals of the local oscillators 5 and 8 into the frequency signal

fr

This signal is amplified by a bandpass amplifier 10 and is fed to the input

a phase shifter 12, the output of which is a reference for the synchronous detector 16,

The operation of blocks 15-27 in the correlometer of FIG. 2 is carried out similarly to the operation of these blocks in the correlometer of FIG. 1. The first and second outputs of the correlometer of FIG. 2 are signals that carry information about the quadrature components of the complex cross-correlation function. - Sivnosti

"

) .. A (t) -Aj (t), (t) -2q j (t) -4lf,

UjCt) - A, (t) -Ai (t) sin 2 (t) -2i / j (t) -dV.

The signal at the third output of the correlometer of FIG. 2 carries information about the module of the complex function of mutual correlation of intensities.

35

)

A; (t) -A (t)

The operation of the correlometer of FIG. 3 is carried out similarly to the operation of the correlometer of FIG.

that the operation of blocks 14-27 is carried out at a difference frequency F. For this, the signal from the output of the multiplier 13 is amplified at a frequency of 2F by a bandpass amplifier 34 and transferred to the difference frequency F by a mixer 35.

In the correlometer of FIG. 4, the signal from the output of the adder 23 is fed to the input of the bandpass amplifier 36 with an adjustable gain factor, which provides amplification of this signal at frequency F with normalizing amplitude control.

the normalization is determined by the amplitude of the signal at which the automatic gain control system, consisting of a band amplifier 36 and an amplitude

detector 37 The output signal of the bandpass amplifier 36, detected by the amplitude detector 38, is proportional to the module of the normalized complex function of mutual correlation of signals

and, .a,

where a is the conditional level adopted as the unit of measurement.

By allocating the normalized modulus of the complex cross-correlation function, it is possible to detect weak correlation dependences between the two input signals. In addition, it is established that these dependences are present while weakening the fading effect, and also eliminates the influence of phase fluctuations of the complex cross-correlation function.

The frequency signal F, which carries information about the module of the normalized complex cross-correlation function, arrives at the signal inputs of synchronous detectors 39 and 40, whose reference inputs receive signals from the outputs of the phase shifter 11 and the quadrature phase shifter 12, respectively. The output signals of the synchronous detectors 39 and 40, simpler, through the corresponding low-pass filters 41 and 42, carry information about the quadratic components of the normalized complex cross-correlation function.

L

U (t) aVosfc Ct) - c (t), UjCt) i sin r4), (t) - g j (t) -L (.

Claims (1)

1. A correlometer containing two receiving channels, each of which consists of an intermediate-frequency amplifier, a local oscillator, and a mixer, whose information input in each receiving channel is the corresponding information input of the correlometer, and the output of each mixer is connected to the input of the corresponding amplifier the intermediate frequency of its receiving capacitive channel, the third mixer, whose inputs are combined respectively with the reference inputs of the mixers of the first and second receiving channels and sub0 50 5 0 g 0 five 0 c respectively connected to the outputs of the oscillators of the receiving channels, the output of the third mixer is connected to the input of the first bandpass amplifier, and the outputs of the first and second amplifiers of the intermediate frequency of the receiving channels are connected respectively to the first and second inputs of the multiplier, whose output is connected to the input of the second bandpass amplifier, the output of which is connected to the information input of the first synchronous detector, characterized in that, in order to expand the class of problems to be solved by separating quadrature components and modes l complex correlation function, it contains a phase shifter, a low frequency filter, a phase detector, a quadrature phase shifter, a second synchronous detector, a first and a second integrator, a fourth and fifth mixers, an adder, an amplitude detector, a third, fourth and fifth fifths amplifiers, with This output of the first bandpass amplifier is connected to the input of the phase shifter, the output of which is connected to the first input of the phase detector, the reference inputs of the first synchronous detector and the fourth mixer and to the input of the quadrature phase shifter Ate, the output of which is connected to the reference inputs of the second synchronous detector, fifth mixer and to the second input of the phase detector, the output of which is connected via a low-frequency filter to the control input of the local oscillator of the first receiving channel, is connected to the output of the second synchronous detector the second band amplifier, the output of the first and second synchronous detectors are connected respectively to the inputs of the first and second integrators, the outputs of which are respectively the outputs of the quadrature components of the com correlation correlation function and are connected to information inputs of the fourth and fifth mixers, respectively, the outputs of which are connected to the third and fourth band amplifiers, respectively, connected to the first and second inputs of the adder, the output of which is connected to the amplitude detector input through the fifth amplitude detector whose output is the output of the modulus of the complex cross-correlation function, 2, the correlometer according to claim 1, about tl and - reading c. the fact that, in order to expand the class of problems solved by separating the quadrature components and the module of the complex function of mutual correlation of intensities, the output of the intermediate amplifier is often TYPES of the first receiving channel through the first quad and the first additional intermediate frequency amplifier inputted in series are connected to the first multiplier input, the intermediate frequency amplifier output of the second reception channel through the second quadrant newly inputted serially connected and the second additional intermediate frequency amplifier is connected to the second multiplier input, the output of the first one band amplifier through the newly introduced series-connected third quad and supplement ny bandpass amplifier connected to the input of the phase shifter 3, a pop correlometer, 1, distinguished by the fact that, in order to isolate quadrature components and a complex cross-correlation intensity function module, the output of the intermediate frequency amplifier of the first receiving channel through the serially connected first quad and the first additional the intermediate frequency amplifier is connected to the first input of the multiplier, the output of the intermediate frequency amplifier of the second receiving channel through the newly introduced series-connected second quad and the second additional y intermediate frequency silicon is connected to the second input of the multiplier, the output of which is through five Q 5 about " five A further additional bandpass amplifier and mixer are connected to the input of the second bandpass amplifier, the second input of the additional mixer is connected to the output of the first bandpass amplifier. A. Correlometer on PP - 3, о t - which is characterized by the fact that, in order to expand the functionality due to the normalization of the output parameters, it contains a band-pass amplifier with adjustable gain, the first and second additional low-pass filters, additional first and second synchronous detectors, additional first and second amplitude detectors, while the information inputs of the first and second additional synchronous detectors and the inputs of the first and second additional 1x amplitude detectors are connected to the output of the bandpass amplifier with adjustable amplification factor, an information input coupled to an output of the adder and controlling koeffip cient gain input coupled; with the output of the first additional amplitude detector, the reference inputs of the first and second additional synchronous detectors are connected to the outputs of the phase shifter and the quadrature phase shifter, respectively, and the outputs of the first and second additional synchronous detectors are connected to the inputs of the first and second additional low-pass filters, the outputs of which are respectively outputs the normalized components of the complex correlation function of the correlometer, and the output of the second additional amplitude An effective detector is the output of the normalized modulus of the correlometer of the complex function of mutual correlation. 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