SU1569737A2 - Apparatus for measuring frequency of input signal of panoramic radio receiver - Google Patents

Abstract

The device is for radio measuring equipment and can be used in panoramic radio receivers and frequency meters. The aim of the invention is to expand the functionality. In order to achieve the goal, a frequency detector 6, a differentiating link 9, a video amplifier 25, an adder 13, are introduced into the device, which allows receiving and indicating signals with an intra-pulse linear modulation frequency. The device also includes an antenna 1, an input circuit 2, a high-frequency amplifier 3, a control unit 4, a frequency sweep generator 5, a mixer 7, an oscillator 8, an intermediate frequency amplifier 10, a frequency detector 11, a differentiator 12, a delay line 14, amplitude detectors 15 , 22 element 16 coincidence, rectifier 17, multiplier 18, video amplifier 19, keys 20, 23, narrowband filter 21, oscillographic indicator 24. 2 Il.

Description

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Stock J Stock Nl

The invention relates to radio metering technology, can be used in panoramic radio receivers and frequency meters and is an improvement to the device according to the author. No. 1272266.

The purpose of the invention is to expand the functionality.

On figi presents the block diagram of the device; 2 shows timing diagrams of the device operation for an input signal with and without linear frequency modulation.

The device (Fig. 1) contains antenna 1, input circuit 2, high frequency amplifier 3, control unit 4, frequency sweep generator 5, frequency detector 6, mixer 7, local oscillator 8, differentiator 9, intermediate amplifier 10 frequency, frequency detector 11, differentiating link 12, adder 13, delay line 14, amplitude detector 15, coincidence element 16, rectifier 17, multiplier 8 video amplifier 19, key 20, narrowband filter 21, amplitude detector 22, key 23, oscillographic indicator 24, video amplifier 25.

In the device, antenna 1, input circuit 2, high-frequency amplifier 3, mixer 7, the second input of which is connected to the output of the local oscillator 8, intermediate-frequency amplifier 10, amplitude

A difficult detector 15, video amplifier 19 key 20 and key 23. Frequency detector 6, differentiator 9, video amplifier 25 are connected to the output of high-frequency amplifier 3, video amplifier 25 is connected to the output of intermediate-frequency amplifier 10, differentiation link 12, sum- gor 13, the inverting input of which is connected to the output of differentiating even 9, rectifier 17, coincidence element 16, the second input of which is connected to the output of the amplitude detector 15, and the output connected to the control input of the switch 20. The output of amplifier 10 of the intermediate frequency is successively connected to delay line 14, multiplier 18, narrowband filter 21, the control input of which is connected to the output of differentiating element 9, amplitude detector 22, the output of which is connected to

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, 50 55 to the control input of the key 23. The outputs of the control unit 4 are connected to the control inputs of the input circuit 2, the high-frequency amplifier 3, the id 8, the generator 5, the output of which is connected to the horizontal plates of the oscillographic indicator. The vertical plates of the oscillographic indicator are connected to the output of the key 23, and the brightness modulation electrode to the output of the amplitude detector 25.

The device works as follows.

Viewing the specified frequency range is carried out using control unit 4, which periodically, with a period Tp, measures the tuning of input circuit 2, high-frequency amplifier 3 and local oscillator 8. At the same time, this unit controls the horizontal scanning of the beam on the oscillographic indicator 24, which used as a frequency axis.

The received signal after passing through the antenna 1, the input circuit 2, the high frequency amplifier 3 is fed to the first input of the mixer 7, to the second input of which the voltage of the local oscillator 8 of the linearly varying frequency is applied.

The output of the mixer 7 generates the voltage of the combination frequencies. The intermediate frequency amplifiers 10 separate the voltage, which simultaneously enters the inputs of the amplitude 15 and frequency 11 detectors. An amplitude detector extracts a pulse envelope with an intra-pulse frequency

modulation (Fig.2, U J, which is according to 1Li,

steps on the first input of element 16

match and through the video amplifier 19 to the first input of the key 20. The keys 20 and 23 in the initial state are always closed. The signal is at the output of the frequency detector 11 (FIG. 2, 11). After passing through the differentiating link 12, the voltage has the form (Fig. 2 and). The signal at the output of the adder 13 (Figures 2, 13) is the same for both the chirp signal and the signal without modulation. This voltage through the rectifier 17 is fed to the input of the coincidence element. In the case of the coincidence in time of the positive pulses from the outputs of the amplitude detector 15 and the rectifier 17, the element 16 coincides and

opens the key with its output voltage 20.

The voltage U (s) of the intermediate frequency from the output of the amplifier 10 of the intermediate frequency is fed to the two inputs of the multiplier 18 directly and through the delay line 14. The output of multiplier 18 produces two components of the signal: total and differential. Allocating a differential frequency voltage using a narrowband filter 21 produces a voltage at its output, which in both cases is a monochromatic oscillation, but at different frequencies.

Using the voltage from the output of the frequency detector 6 (Fig. 2, and) after the differentiator 9 to control the frequency tuning of the narrowband filter 21, the device allows fine tuning of the narrowband filter 21 to the difference frequency as in the case of a simple pulse signal, and in the case of a chirp pulse signal with different parameters of its modulation (Fig. 2, Ug,). The signal extracted by the narrowband filter 21 is detected by the amplitude detector 22. From the output of the amplitude detector 22, the voltage in the case of a signal at the output of the narrowband filter 21 is fed to the control input of the key 23 and opens it. In this case, the video output from the output of the video amplifier 19 through the public keys 20 and 23 enters the vertical plates of the oscillographic indicator 24, as a result of which the frequency mark is formed on the screen of the latter, the position of which on the horizontal scan uniquely identifies the received signal on the main channel. In the case of intra-pulse chirp, the signal from the output of differentiating element 9 (Fig. 2, Ug) is amplified by video amplifier 25 and is fed to the luminance modulation electrode of oscillographic indicator 24, increasing the luminance frequency of the frequency mark in proportion to the rate of change of the frequency inside the pulse.

In the case of receiving a pulse signal in the mirror channel, the voltage at the output of the adder 13, both without intra-chirp, and in the presence of

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intrapulse modulation has a polarity opposite to that which occurs when a signal is received on the main channel, since the rate of change of the frequency of the local oscillator 8 relative to the frequency of the received signal changes its sign to the opposite. The voltage at the output of the rectifier 17 is missing, the element 16 does not work, the key 20 does not open, and the signal from the output of the video amplifier 23 to the input of the key 23 does not pass. In the case of receiving a pulse signal on the first combination channel, the resulting difference frequencies do not fall into the passbands of the narrowband filters and are suppressed, the key 23 remains closed and the signal from

0, the output of the key 20 on the vertical deflecting plates of the oscillographic indicator 24 is not received. When a signal is received on the second combinational channel, an analogue of the 5 situation arises, the keys 20 and 23 remain closed.

The proposed device in comparison with the known allows you to receive and display pulsed signals with

Q is the intrapulse linear frequency modulated by excluding the possibility of skipping them in a fast frequency search. This is achieved by compensating for the effect of the change in the carrier frequency of the signal inside the pulse on the algorithm of the device operation in the signal processing cycle.

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Claims (1)

Invention Formula A device for measuring the frequency of the input signal of a panoramic radio receiver by auth.St. No. 1272266, characterized in that, in order to expand its functionality, an adder and a second frequency detector, a second differentiating link and a second video amplifier, are inputted in series to the high frequency amplifier output, and the second differentiator output is connected to the control input of the narrowband filter, the output of the video amplifier is connected to the luminance modulating electrode of the oscillographic indicator, the adder is connected between the differentiating link and the rectifier, and the second input is the summator The ora is connected to the output of the second differentiating link. Figg