SU907456A1 - Generator signal frequency fluctuation meter - Google Patents

Description

This invention relates to radio measurements. A device for measuring oscillator frequency fluctuations is known, comprising two mixers, a traveling wave tube connected through a phase shifter to a generator and through a delay line to a measured oscillator, a local oscillator with an automatic frequency control system (AFC), an indicator, an electron counter frequency meter, a sawtooth generator p. The disadvantage of this device is its complexity. The closest to the invention to the technical essence is a meter that contains a reference oscillator, the output of which is connected to one input of the phase detector, the second input of which is connected to the output of the generator being tested, and the output of the phase detector is connected to the input of the spectrum analyzer and the amplifier the reference oscillator through a series-connected DC amplifier and the first low-pass filter, the second low-pass filter and the indicator 12. The disadvantage of this device is the length noe measurement time due to the necessity of a long calibration process. The purpose of the invention is to reduce the measurement time. The goal is achieved by connecting the oscillator frequency signal to the oscillator signal, which contains a reference oscillator, the output of which is connected to one input of the phase detector, the second input of which is connected to the output of the checked oscillator, and the output of the phase detector is connected to the input of the spectrum analyzer through an amplifier the control input of the reference oscillator through a series-connected DC amplifier and the first low-pass filter, the second low-pass filter

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and an indicator, a calibration signal generator, two signal ratio meters and a synchronous detector are entered, one input of which is connected to the amplifier output, the second input is connected to the output of the calibration signal generator and the second input of the reference generator, and the output of the synchronous detector is connected to the first low-pass filter the inputs of the meters relate the signals, the second input of the first of which is connected to the amplifier input, and its output is connected to the generator output of the calibration signal, and the output of the spectrum analyzer is Inonii to a second input of the second meter relationship signals, and its output is connected to vhoyU indicator.

The drawing shows a structural electrical circuit of the device.

The device contains a reference generator 1, a phase detector 2, a DC amplifier 3, k and 5 low-pass filters, amplifier 6, a spectrum analyzer 7, an indicator 8, a calibration signal generator 9, 10 and 1 signal ratio meters, a synchronous detector 12, Generator 13, the meter operates as follows.

The signals of the generators 1 and 13 are simultaneously fed to the inputs of the phase detector 2. The signal of the generator 13 with respect to the signal of the generator 1 is squared to suppress the amplitude fluctuations of the signals. This is achieved by using a phase locked loop (PLL) which consists of a low pass filter k and a DC amplifier 3. The PLL band is chosen narrow enough so that the fluctuations of the oscillators in the analyzed band are mutually independent. At the same time, in the PLL band, the frequency of the oscillator 1 is adjusted to the frequency of the oscillator 13. In this case, the output of the phase detector 2 separates a noise signal proportional to the frequency noise of the oscillators. The signal from the output of the phase detector through the amplifier 6 is fed to the spectrum analyzer. The result of the analysis is recorded using indicator 8. For calibration, the meter at the input of generator 1 is supplied with a modulating signal of generator 9. The level of the modulating signal

is controlled by the output signal of meter 10. Due to the modulation in the spectrum of the signal from generator 1, a pilot signal appears, which is extracted by the synchronous detector 12. 8 as a reference voltage, the generator signal 9- Constant voltage Uf is supplied to the input of the synchronous detector, . proportional to the level of the pilot signal, from the output of the low-pass filter 5 is fed to the first input of the meter 10. Its second input from the output of the phase detector 2 receives a constant voltage, the level of which is K and., (i (where 1) and UQ amplitude oscillator signals, respectively, K is the conversion factor of the phase detector. The meter 10 does not provide a control / 1 signal a to the generator 9 only in one case, when - A, where A is a constant value, is determined

In the remaining 8 cases, the output signal of the meter 10 controls (decreases or increases) the level of the modulating signal until the ratio A is reached, i.e. The level of piUn-o lot signal depends on the levels of CI -

generator generators and the conversion ratio of the phase detector,

and

and the relationship is maintained by standing. in this case, the output

amplifier 6, there is a pilot signal with a calibrated level, against which the noise level of the generators is measured using a spectrum analyzer. Accuracy of maintenance of the displayed level of the pilot signal is determined by the stability of the channel conversion coefficient: amplifier 6, synchronous detector 12, low pass filter 5 and meter 10, and can reach 3-5. A signal proportional to the calibrated level of the pilot signal from the output of the low pass filter 5 is fed to the first input of the meter 11, the second input of which receives a signal proportional to the level of the measured fluctuations. At the output of this meter, a signal is formed that is proportional to the ratio of the input signals. This signal is fed to an indicator that directly counts the measured order.

Claims (2)

Invention Formula A generator of frequency oscillations of the generator signal, containing a reference oscillator, the output of which is connected to one input of the phase detector, the second input of which is connected to the output of the generator being tested, and the output of the phase detector is connected to the input of the spectrum analyzer via an amplifier of the first filter a low pass, the input of which is connected to the output of a dc amplifier, a second low pass filter and an indicator, characterized in that, in order to reduce the measurement time , a calibration signal generator is inserted into it; two signal relationship meters and an synchronous detector, one input of which is connected to the amplifier output, the second input is connected to the output of the calibration signal generator and the second input of the reference oscillator, and the output of the synchronous detector is connected to the first inputs through the second low-pass filter signal ratio meters, the second input of the first of which is connected to the output of the amplifier, and its output is connected to the input of the calibration signal generator, with the output of the spectrum analyzer connected with the second input of the second meter relationship of the signals, and its output is connected to the input of the indicator. Sources of information taken into account in the examination 1. USSR Author's Certificate No. 665278, class G 01 R 27/06, Acc.12.76. 2. Galin A.S. The range of quartz stabilization of the microwave. M., Holy Hail 1976, p. 160