SU665278A1 - Device for measuring mean rate of variation of frequency and linearity of modulation characteristics of frequency-manipulated generators - Google Patents

Description

A traveling wave tube, an additional intermediate frequency amplifier, a frequency detector and an integrator connected in series between the multiplier output and a video amplifier input are given, as well as a low-pass filter, an amplifier and a frequency controller connected in series between the integrator output and the heterodyne control input, and a traveling wave lamp connected between the output of the delay lynn and the second input of the mixer, the spiral of the traveling wave tube is connected to the output of the high-frequency generator, and the first anode of the bulb is running th wave phase shifter connected to the output of the attenuator.

The structural electrical circuit of the described device is shown in the drawing.

The device contains a sawtooth voltage generator 1, a mixer 2, a delay line 3, a traveling wave tube 4, a high frequency generator 5, a phase shifter-attenuator 6, an intermediate frequency amplifier 7, a multiplier 8, an additional 9 intermediate frequency amplifier, frequency detector 10 , integrator I, video amplifier 12, oscillographic indicator 13, local oscillator 14, electronic counter frequency meter 15, frequency divider 16, frequency ruler 17, amplifier 18, low-pass filter 19. The drawing also shows the generator 20 under investigation.

The principle of operation of the device is as follows.

The extension of the range of measured frequency deviations from the linear law is due to the frequency shift in TWT 4 of the delayed signal in line 3. This shift is accomplished by applying to the slow-wave system (not shown) of the TWT 4 a high-frequency voltage of the high-frequency generator 5. In this case, a multi-frequency signal is produced at the output of the TWT 4 with the frequency

(+ "Z ±" / sd,

where / sd - frequency generator 5;

/ o - frequency generator 20;

, 2, ...;

Tz - Delay time in line 3 delay;

Ko - average speed coefficient

frequency changes.

The harmonic with the frequency / ОЧ-- оТ.з- /ДС is compensated for by applying a high-frequency generator 5 signal to the spiral and the first TWT anode 4. The indicated signal to the TWT spiral 4 is fed directly, and to the first anode through the rotator rotator 6, which provides adjustment amplitude and phase shift of the generator signal by l / 2. Filtering the higher harmonics of the output signal of the mixer 2 is carried out by the intermediate frequency amplifier 7. So the signal frequency on

the output of the intermediate-frequency amplifier 7 is equal to / (oTz + / sd. Decreasing Tz will measure large deviations from the linear law and will not cause beats of the delayed and non-delayed signals. For this same device, frequency detector 10 is included with the integrator 11. the frequency shift in TWT 4, and the transformation in multiplier 8 increase the transition frequency of the frequency detector, hence the linear portion of its discriminatory response is expanded.

The corresponding reduction and expansion of the frequency detector bandwidth, the decrease in the slope of the overall discriminatory characteristics of the device are compensated by increasing the gain in the path of the video amplifier 12 and the additional amplifier 9 intermediate frequency.

The frequency at the output of the intermediate-frequency amplifier 7 is equal to KoTz - (- / cf. B and does not multiply 8, and the additional intermediate-frequency amplifier 9 uses a local oscillator 14 to convert this

frequencies so that it is equal to the transition frequency of the frequency detector.

The frequency tuning rate can be determined from the known frequency of the local oscillator 14 by fixing the zero discrimination characteristic of the frequency detector 10 at a constant frequency of the high frequency generator 5.

The limit of change in the average frequency tuning rate is determined only by the band of the intermediate frequency amplifier 7 and the frequency tuning range of the local oscillator 14.

Reducing the number of operations and improving the accuracy of measuring the average speed is achieved by connecting the frequency controller 17 to the integrator output through the amplifier 18 and the low frequency filter 19. In this case, the frequency deviation at the input of the frequency detector, caused by a change in the average

the frequency tuning rate leads to a change in the constant component at the output of the low-pass filter 19. This change in constant component is amplified in amplifier 18 and fed to the input

The governor is 17 frequencies. Changes in the frequency of the local oscillator, proportional to the change in the average tuning rate / Co, are recorded by an electron-counting frequency meter 15. The accuracy of determining the average speed

frequency tuning of the oscillator 20 is increased by eliminating subjective measurement errors, better fixing the zero of the transient response, and using an electron-counting frequency meter.

Claims (1)

Invention Formula A device for measuring the average rate of change of frequency and linearity of the modulation characteristics of frequency-modulated oscillators, comprising a sawtooth generator, a voltage whose output is connected to the control input of the generator being studied, one output of which is connected to the first input of the mixer and the second , high-frequency generator, the output of which is connected to the input of the phase shifter of the attenuator, the local oscillator, the output of which is connected to the input of the electron-counting frequency meter and divides through The frequency is connected to the input of the sawtooth voltage generator and the oscillographic indicator, the second input of which is connected to the output of the video amplifier, and the output of the mixer is connected to the first input of the multiplier through the intermediate frequency amplifier, which, in order to expand frequency range and increased measurement accuracy, a traveling-wave tube, an additional intermediate frequency amplifier, a frequency detector and an integrator, included in it between the multiplier output and the video amplifier input, as well as a low-pass filter, an amplifier and a frequency controller, connected in series between the integrator's output and the local oscillator control input, the traveling wave tube connected between the output of the delay line and the second input the mixer, its coil is connected to the output of the high-frequency generator, and the first anode is connected to the output of the phase-shifter.