SU1406506A1 - Device for measuring frequency of input signal of panoramic radio receiver - Google Patents

Abstract

A device for measuring the frequency of the input signal of a panoramic radio receiver contains antenna 1, input circuit 2, high-frequency amplifier 3, mixer 4, intermediate-frequency amplifiers 5j, amplitudes Hbie detectors 7, -7, elements 9-9. matches, delay lines, narrow-band filters, oscillographic indicators 11 i- C, the device has a wide range of frequency signal search, 2 Il.

Description

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The invention relates to a radio-measuring technique and can be used in panoramic radio receivers i-vacTOTOMepaji.

The purpose of the invention is to expand the range of frequency search signals without expanding the range of the frequency tuning of the local oscillator.

Fig, 1 shows a structural diagram of the proposed device; 2 shows timing diagrams for the operation of the device.

The device contains serially connected receiving antenna I, input circuit 2, high-frequency amplifier 3, mixer 4, intermediate-frequency amplifiers 5 and 5, to the output of which two signal processing paths are connected, each of which consists of a series-connected narrow-band filter (BDB), amplitude detector 7 (7 ,,), line 18 (83), delay, element 9 (9), coincidence, the second input of which through a series-connected narrow-band filter 6 (6) and amplitude detector 7 (7) is connected to the output amplifier 5 (5) intermediate frequency ideoamplifier 10, (S) and the vertical electrode of the oscillograph - kecKoro indicator 11 (11 ,,), To the output of the amplitude detector 7 (7j) | sequentially. delay lines (8), element 9 (9) coincidence, video amplifier) and a vertical oscillograph electrode - jecKoro indorsator 1 1, (114). The outputs 15 of the control unit 12 are connected to the upstream inputs of the input circuit 2, the high-frequency amplifier 3, the hetero-Kwa 13 whose output is connected to the second input of the mixer and the frequency sweep formation unit 14, the output of which is connected to the horizontal electrodes of the oscillographic indicators llj , P, P and 11.

The device works as follows.

Viewing the specified frequency range Df is determined by the control unit 12, which periodically with the period Tj changes the input circuit 2, the high frequency amplifier 3 and the local oscillator 13, according to the law, and through the horizontal frequency shaping unit 14 scanning the oscillographic indicators 11,

s 0 5 0 s d 5

0

five

II, j, 11, and 1 l, while the indicator sweep line is used as a frequency axis, the length of which corresponds to the range of viewed frequencies.

The received pulse signal from the output of the receiving antenna 1 through the input circuit 2 and the high frequency amplifier 3 is fed to the first input of the mixer 4, to the second input of which is supplied the voltage Ut, (t) of the heterodyne 13 of the linearly varying frequency:

Ur (t) Ur-cos (2 (Tj- t - + if),

Df where) i is the rate of change of the hourf then you are the ff-heterodyne, (f is its phase.

At the output of the mixer 4, signals of the following frequency are formed:

 z +), t - f, -f, p + t;

 fi fc where the second index denotes the harmonic frequency number of the local oscillator, which participates in the frequency conversion of the received signal, d the first index denotes the channel on which the signal is received;

 the rate of change of the second harmonic of the heterodyne frequency.

The tuning frequency f and the band d, the passband of the intermediate frequency amplifier 5 are equal to

f - 3 f И1 2 Р

i3f, fnp

The tuning frequency f and the passband Jfj of the amplifier 5 intermediate: frequency are equal to

12

  etc

The bandwidth of the transmission of narrowband filters 6 and 6 is equal to f ,, and narrowband filters 6 1 and dB - / I f.

However, only the converted signal at frequency f, falls into the Jf band, the transmission of amplifier 5 of the intermediate frequency. The specified signal from the output of amplifier 5, (Fig. 2a) is fed to the input of narrow-band filters 6, and 6, in which it is converted into two radio pulses (Figs. 26 and 2c) with a duration of T --- and a time shift

gom between them equal to T pi - Y

(where /) f p is the frequency separation between the tuning frequencies of narrow-band filters 6 (6) and 6 (6), df f f 4 f ((, 2). These radio pulses are converted to video pulses (figs, 2d and 2d) in amplitude detectors 7 and 7. JS video output (Fig. 2d) from the output of the amplitude detector 7 is fed to the input of delay lines 8 and 8. The delay time of delay lines 8 and 8 j is chosen to be 3 Tr1, and delay lines 8 and

H

 Tr. Output video signals

line 8, delay (figure 2) and the output line 8-2. delays (Fig.2z) are received respectively at the first inputs of the elements 9: and 9 matches, the second inputs of which receive the video signal (Fig.2) from the output of the amplitude detector 7j. Since the pulses arriving at the two inputs of the element 9 /, coincidence (fig. 2d and 2e) coincide in time, the element 9 of coincidence triggers. Its output video impulse (Fig. .2g) through video amplifier 10 ;, is fed to the vertical trode of the oscillographic indicator 11, where a frequency label is formed, the position of which on the horizontal scan uniquely identifies the carrier frequency fj of the received signal.

The above operation of the device corresponds to the case of receiving a signal on the main channel at a frequency f.

If the signal is received in the mirror channel at the frequency fj, then in mixer 4 it is converted into signals of the following frequencies;

f

31

3fr f np-r, t;

3

31 2f, + - t

However, only the converted signal at the frequency f 3 falls into the passband ufi of the passband of the intermediate frequency amplifier 5. This signal is fed to the inputs of the narrow-band filters 6j and 6, the outputs of which form radio pulses of duration T and a time shift between them equal to T p ,. These radio pulses are converted into amplitude detectors 7j and 7 into video pulses. In this case, the coincidence element 9j is triggered and the carrier frequency f of the received signal is evaluated on the oscillographic indicator screen.

iiv

0

If the signal is received on the first combinational channel at a frequency f, then in mixer 4 it is converted to signals of the following frequencies:

 K1 fp -I

17 2fr, t.- f ,, fnp +.

However, only the converted signal at frequency f. falls into the bandwidth / Ifi bandwidth of the amplifier 5 ;, intermediate frequency. At the output of the narrowband filters 6 and 6j, radio pulses are formed (Fig. 26 and 2c) long

/ if - and temporal shift Jfp

5 T,

gom between them, equal to T p,

Yy

0

five

In this case, a coincidence element 9 is triggered, the output video pulse (Fig.2i) of which forms a frequency mark on the oscillographic indicator screen, whose position on the horizontal scan uniquely determines the carrier frequency fc of the received signal.

If the signal is received on the second combinational channel at frequency fx, then in mixer 4 it is converted to signals of the following frequencies:

0

f 11 -f

0

("G -2fr -

-ll- L K1 f g J l

However, only the converted signal at the frequency fii falls into the 4f bandwidth of the intermediate frequency amplifier 5. In this case, the frequency f of the received signal is estimated on the screen of the oscillographic indicator 1 C.

If signals are simultaneously received on the main, mirror, and combinational channels, all units of the device participate in the operation.

Thus, the proposed device (as compared to the known ones) provides for expanding the frequency search range of signals without extending the frequency tuning range of the local oscillator, which is achieved by separate reception of signals along the main mirror and combinational channels, and separate reception of signals through the indicated channels

tuning and bandwidth of the intermediate frequency amplifiers and narrowband filters, as well as the delay time of the delay lines.

0

five

gain formula

one

A device for measuring the frequency of the input signal of a panoramic radio receiver, containing a series-connected antenna, an input circuit, a high-frequency amplifier, a mixer, in (the second input of which is connected to a high-frequency oscillator, an amplifier of an exact frequency, as well as the first am- P | power detector, the first element with | falling, the first video amplifier, the output of which is connected to a vertical electrode of an oscillographic indicator, the horizontal electrode of which is connected to the output of a frequency sweep shaping unit, a control unit The first, second, third and fourth outputs of which are connected respectively to the control inputs of the input circuit, a high frequency amplifier, a local oscillator, and a frequency sweep shaping unit, characterized in that, in order to expand the frequency range of searching for signals, a second intermediate amplifier is introduced into it hf / M

14065066

the first and second filters, the second amplitude detector, the first and second delay lines, the second matching element, the second video amplifier and the second oscillographic indicator, the first narrow-band filter, the amplitude detector, the delay line, the matching element connected to the output of the AFC, video amplifier, connected in series to the output of the first amplitude detector are a second delay line, a second coincidence element, a second video amplifier, and vertical plates of the second axis An illographic indicator, the horizontal plates of which are connected to the output of the frequency scanner forcing unit, the second inputs of the first and second coincidence elements are combined and connected to the output of the second amplitude detector, whose input is connected to the output of the second narrowband filter, its input connected to the output of the second amplifier intermediate often you.

Claims (1)

Claim) A device for measuring the frequency of the input signal of a panoramic radio receiver, comprising a series-connected antenna, an input circuit, a high-frequency amplifier, a mixer, the input of which is connected to the local oscillator output, an intermediate frequency amplifier, as well as a first amplitude detector, a first matching element, a first video amplifier, the code of which is connected to the vertical electrode of the oscilloscope indicator, the horizontal electrode of which is connected to the output of the frequency scanning unit eniya first Tille and fourth outputs of which are connected respectively to the control inputs of the input circuit of a high frequency sweep of the frequency of formation of a N <) of the search signal has been entered in a second amplifier of intermediate h> , the second, tre, amplifier, local oscillator and the unit is characterized by the fact that, in order to expand the frequency range of 10 amperes, the first and second filters, the second amplitude detector, the first and second delay lines, the second coincidence element, the second video amplifier and the second oscillographic indicator, and to the output AFC connected in series with the first narrow-band filter, amplitude detector, delay line, matching element, video amplifier, connected to the output of the first amplitude detector in series with the second line of the rear LCD, the second coincidence element, the second video amplifier and the vertical plates of the second oscilloscope indicator, the horizontal plates of which are connected to the output of the frequency sweep generation unit, the second inputs of the first and second coincidence elements are combined and connected to the output of the second amplitude detector, the input of which is connected to the output of the second narrow-band filter , your input connected to the output of the second amplifier of the intermediate frequency you. Subscription VNIIIPI Order 3187/40 Circulation 772_____ Prod ..- polygr. ave, city of Uzhhorod, st. Project, 4