SU828104A1 - Device for measuring average variation rate of frequency-modulated generator modulation characteristic linearity and frequency - Google Patents

Description

through the phase shifter - with the third input of the traveling-wave tube, the first and second switches, an additional mixer and an additional intermediate frequency amplifier, a frequency multiplier and an additional frequency detector, the output of which is connected to the first inputs of the first and second switches, are entered in series, the second inputs which are connected to the output of the main frequency detector, while the output of the first switch is connected to the input of the low-pass filter, the output of the second breakers connected to the input of the integrator, a first input of an additional mixer connected to the input of the frequency, the second input of the additional mixer connected to the output of the high frequency generator, an additional amplifier of the intermediate frequency output is connected to the second input of the second main mixer, and the input frequency multiplier connected to the input of the main frequency detector.

The drawing shows a structural electrical circuit of the device.

The diagram shows mixer 1, intermediate frequency amplifier 2, mixer 3, intermediate frequency amplifier 4, delay unit 5, traveling wave tube 6, phase shifter 7, frequency detector 8, frequency divider 9, high frequency generator 10, FM oscillator I, frequency meter 12 , local oscillator 13, lowpass filter 14, integrator 15, sawtooth voltage generator 16, indicator 17, control unit 18, error signal amplifier 19, video amplifier 20, frequency multiplier 21, unit 22, frequency detector 23, mixer 24, switches 25 and 26.

The operation of the device is as follows.

The voltage of the FCAB frequency from the output of the generator 10 is supplied to the frequency divider 9, which generates the start-up pulses of the FCN 16 and the indicator 17. From the output of the GPN 16, the control voltage is applied to the input of the FM oscillator I. The FM oscillator generates a signal with a linear-varying frequency arrives at the input of the wideband differentiating quadrupole. The differentiating quadrupole contains a mixer 1, a delay unit 5 with a delay time T3 and a single-band frequency converter on TWT 6. Compensation of one of the sidebands is achieved by modulating TWT 6 on two electrodes with an output voltage of generator 10 with a frequency of one. From the output signal of the differentiating quadripole amplifier 2, the component of the first intermediate frequency fnp is extracted, which is fed to the input of the mixer 3. The second input signal of the mixer 3 is fed to the signal of the difference frequency Pp Pt-FCAB

generator 10 and the local oscillator 13. From the output of the mixer 3, the amplifier 4 extracts the signal with the frequency

, / g + dt + (/). (1)

Analysis of expression (1) shows that Fffp does not depend on / dvd and its instabilities. The signal of the second intermediate frequency is fed to the frequency detector 8 and through the frequency multiplier 21 with the multiplication factor L to the frequency detector 23. The frequency detectors 8, 23 have transition frequencies FU, respectively

F,:, to F NF, at + C () O

From the outputs of the frequency detectors 8, 23, the voltage proportional to ft3 + (t) and Л 7т; з + Ц0, arrive respectively at the first and second inputs of switches 25 and 26. The output of switch 25 is connected

through a serially connected low-pass filter 14, an error signal amplifier 19, and a block 18 to the local oscillator 13, forming a feedback circuit of a pulse frequency auto-tuning system. In the filter

14 low frequency integrates the pulse error signal. Therefore, a pulse frequency control system monitors frequency changes proportional only to the average tuning rate of the frequency-modulated oscillator I. Changes in the frequency of the local oscillator 13 are recorded by an electronically counting frequency meter 12. The rate of the frequency tuning Y is determined by the frequency of the local oscillator 13.

The output of switch 26 is connected via a serially connected integrator 15 and video amplifier 20 to an oscillographic indicator 17, by which frequency deviations from a linear law are measured. The impulse-controlled frequency-tuning system performs variations / pr due to the average frequency tuning frequency of the frequency-modulated oscillator I. Therefore, the output voltage of the frequency detector 8 (23) is determined by the non-linearity of the modulation characteristic of the frequency-modulated oscillator 11 ((0) Application of frequency multiplier 21 and frequency detector 23 extends the lower limit of the range of measured values

g

in mNraz, where -

amplitude-frequency characteristics of frequency detectors 23 and 8.

Using the switches 25, 26 selects the required range of measured

quantities Depending on the position of the switches 25, 26, the device measures the characteristics of frequency-modulated oscillators: - with a high frequency tuning speed and pronounced non-linearity of the modulation characteristic, which is achieved by connecting the frequency detector 8 to the integrator 15 and the low-pass filter 14 (switches 25 and 26 position

one);

- with a high frequency tuning rate and a slight non-linearity of the modulation characteristic, which is carried out by expanding the lower limit of the linearity measurement range of the modulation characteristics by mN times by connecting the output of the frequency detector 23 to the integrator 15 (switch 25, position 1, switch 26, position 2) ;

-with a low frequency tuning rate and a pronounced non-linearity of the modulation characteristic, which is achieved by expanding the lower limit of the measurement range of the average frequency tuning rate tpl times by connecting the output of the frequency detector 23 to the low-pass filter (switch 25, position 2, switch 26, position 1 );

- with a low frequency tuning rate and a slight non-linearity of the modulation characteristic, which is achieved by expanding the lower limit of the range of measured values rnN times by connecting the output of the private detector 23 to the integrator 15 and the low-pass filter 14 (switches 25 and 26, position 2).

Technically, frequency multiplication is simply implemented in times. Therefore, using a frequency detector of 23 seconds, extends the lower limit of the range of measured values by 10 times.

The formation of start-up pulses from the voltage of the generators 10 increases the stability of the pulse-locked frequency control system in the range of measured values and, accordingly, increases the measurement accuracy.

Claims (2)

1. Movshovich ME Semiconductor frequency converters. L., “Energie, 1974, p. 23. 2. Application No. 2426194 dated June 30, 1997, according to which a positive decision was made. (prototype). G G1 one/ -and / 7