SU1035531A1 - Device for checking frequency deviation meters - Google Patents

Abstract

A DEVICE FOR DEVELOPING FREQUENCY MEASURING MEASURES, containing an index sensor, a modulating voltage generator, the output is connected to the first frequency divider and to a controllable attenuator connected to the generator of frequency-modulated signals, and an spectrum analyzer that is equipped with an attenuator connected to the frequency-modulated signal generator, and an spectrum analyzer equipped with an attenuator connected to a frequency-modulated signal generator, and an spectrum analyzer equipped with an oscillator, which is connected to an frequency generator in order to differentiate the range of modulating frequencies and deviations, a second frequency divider, a reference oscillator, a third frequency divider, a selector, a counter, a code dividing unit and a frequency deviation indicator were introduced, the second frequency divider connected to a frequency modulated signal generator and a spectrum analyzer, a reference oscillator through the third frequency divider is connected to the first input of the selector, the second input of which is connected to the output of the first frequency divider, and the output through the counter is connected to the first input of the block divider s, a second input coupled to an F setter indices, and output is connected to kodoupravl emym attenuator and frequency deviation indicator. AND

Description

This invention relates to radio electronics, in particular to radio measuring equipment.

A device for calibrating frequency deviation meters (IDCs) is known, which contains series-connected modulators of a modulating voltage and frequency-modulated (FM) signal, and | A spectrum analyzer fixing zero values of the carrier frequency at the corresponding C13 modulation indices.

A disadvantage of this device is the considerable laboriousness of verification and the limited range of calibrated modulation indices, 2.405 (20-30).

The closest to the present invention is a device for calibrating frequency deviation meters, which reduces the laboriousness of the calibration and allows you to calibrate the modulation indices p 2.405. The device contains a modulating voltage generator, the output of which is connected to the first frequency divider, a code-controlled attenuator, an FM signal generator, an FM frequency signal multiplier, a spectrum analyzer, a frequency divider, an electron-counting frequency meter, a frequency divider signal and an index setter 2}.

A disadvantage of the known device is the limited range of indices in the range of large values (B730), which are clipped on zeroes (L730), which is associated with insufficient speed with large modulation indices and difficulties in visual indication of the zero-spectral component with the carrier frequency.

The purpose of the invention is to expand the range of modulating frequencies and deviations.

The goal is achieved in that a device for calibrating frequency de-frequency meters, containing an index sensor, a modulating voltage generator, the output of which is connected to the first frequency divider and to a kodo controlled attenuator connected to a generator of frequency modulated signals, and a spectrum analyzer, A second frequency divider, a reference oscillator, a third frequency divider, a selector, a counter, a code division unit, and a frequency deviation indicator were introduced, the second frequency divider being connected to the FM signal generator and analysis. ore of the spectrum, the reference generator through the third frequency divider is connected to the first input of the selector, the second input of which is connected to the output of the first frequency divider, and the output through the counter is connected to the first input of the code division unit, the second input of which is connected to the index setting device, and the output is connected to coding control attenuator and frequency deviation indicator.

The drawing shows a block diagram of the device.

The device comprises a modulating voltage generator 1, an attenuator 2, a code control generator

3WM signal, second divider 4 frequency FM signal, spectrum analyzer 5, quartz reference oscillator b, first divider 7 baseband frequency, third divider 8 frequency reference quartz oscillator, selector 9, counter 10, sensor 11 indices, block 12 dividing codes and indicator 13 deviations.

The device works as follows.

The modulating voltage from generator 2 is fed to the generator 3 of the FM signal through a code-controlled attenuator 2. The frequency deviation is proportional to the transmission coefficient of the code-controlled attenuator, i.e. code.

The signal from the output of the 3 FM signal generator is fed to the TURB checked and, through the divider 4, the frequency of the FM signal to the spectrum analyzer 5. By setting the division ratio of the divider

4 FM signal frequencies equal to 1. By adjusting the level of the modulating voltage, the first zero of the Bessel function i 2.405 is detected using the spectrum analyzer 5, the frequency deviation is equal to D- 2.405F

Voltage. Generator 1 is fed to a period meter formed by a crystal oscillator 6, frequency divider 7 and 8, selector 9 and counter 10. Code L-j at the output of counter 10 is proportional to the period of the modulating frequency F and is related to it by the ratio

s-531b., t-pu

where € Q is the frequency of the reference crystal oscillator;

And - the division factor of the divider 7 frequency modulating voltage

VI is the division factor of the divider 8 frequency of the reference crystal oscillator.

In the setting unit of 11 indices, the zeros of the BesseL function are stored as binary equivalents of numbers (| C 2.405, Pa, fj, 30.6), which are fed to the input of block 12 for dividing the codes as a dividend, and the input of the divider is the code Mt

At the output of the block 12 division of the codes is the result

"6" -

.t

When the frequency of the crystal oscillator is 1 50 MHz, Hd 20E, by setting m - 20, h 1, we get P "P In this case, the device works like a prototype, the Wu code goes to the code-control attenuator, which allows the carrier to keep zero when changing and f .

Perelyuchyu divider 4 frequency division ratio K and setting

205

K, we get a deviation of frequency

You are a FM generator that is used for IDH calibration. At the output of the 4 frequency divider, the de viati ji is obtained. f on the carrier to.

Rebuilding the spectrum analyzer on the frequency imgen watching spectrum

The FM signal with an index of 2, 30.634, which is easily monitored by a spectrum analyzer, and the deviation value is counted by indicator 13. Consequently, the range of calibrated indices is expanded K times.

The installation time of the deviation is determined by the ieTCH value where time

calculations in block 12 division of codes and at R | c 30 Hz and the use of modern arithmetic devices does not exceed 1s.

o The device is operational with modulation index A 2.405. In this case, the division factor of divider 4 is set to 1 and its output pulses are applied to a spectrum analyzer. By rearranging the last to the P-th harmonic of the carrier of the FM signal, where the modulation index is equal to ft

R;

AT

get on carrier index

In this case, the coefficients vn and and must be chosen from the ratio

W p

 Thus, paoiming of the range of frequency deviation indices calibrated by zero Bessel function is ensured and the shortening is shortened.

Claims (1)

DEVICE FOR TESTING FREQUENCY DEVIATION MEASUREMENTS, comprising an index adjuster, a modulating voltage generator, the output of which is connected to the first frequency divider and to a code-controlled attenuator connected to a frequency-modulated signal generator, and a spectrum analyzer, characterized in that. in order to expand the range of modulating frequencies and deviations, a second frequency divider, a reference oscillator, a third frequency divider, a selector, a counter, a code division unit and a frequency deviation indicator are introduced, the second frequency divider connected to a frequency-modulated signal generator and a spectrum analyzer, a reference the generator through the third frequency divider is connected to the first input of the selector, the second input of which is connected to the output of the first frequency divider, and the output through the counter is connected to the first input of the code division unit, sec whose input is connected to the index setter, and the output is connected to a code-controlled attenuator and a frequency deviation indicator. >