SU1352614A1 - Arrangement for visual matching of frequencies in radio channel - Google Patents

Abstract

The invention relates to radio measurements and can be used in metrology and single-time systems for calibrating means of measuring frequency and time. The purpose of the invention is to expand the functionality by providing a comparison of the frequency of the local oscillator with the exemplary carrier frequency of the radio station, which is pulsing. The device contains a receiver 1, a Schmitt trigger 2, an oscilloscope 3, a key 4 connected in series to the second Schmitt trigger 5 and a generator 6 of stepwise varying voltage. The device allows you to turn the local oscillator on the exemplary carrier frequency of the radio station, leading the transmission in a pulsed mode, as well as to make a comparison of frequencies in the event of a short disruption of the radio frequency transmission channels. 1 il. § L

Description

The invention relates to radio engineering, namely to radio measurements, and can be used in metrology and a single time system for calibrating means of measuring frequency and time.

The purpose of the invention is to expand the functionality by providing a comparison of the frequency of the local oscillator with the exemplary carrier frequency of the radio station, which is pulsing.

The drawing shows a structural

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The scheme of the device for visual eligibility is 15 kilograms, expressed in frequency transfer over the radio channel.

The device for visual comparison of frequencies over the radio channel contains a receiver 1 connected to the Schmitt trigger 2 input, the output of which is connected to the first external synchronization input of the oscilloscope 3 and the control key 4, and the second trigger 5 connected in series and the generator 6 (GSIN), the output of which through the key 4 is connected to the signal input of the oscilloscope 3.

The device works as follows.

In the initial state, receiver 1 receives a sequence of radio pulses with an exemplary carrier frequency f. The amplified pulses with radio-frequency filling are fed to the input of a Schmitt trigger 2, where a part of the periods of radio-frequency filling is converted into packs of rectangular pulses. These pulses are applied to the first input of the oscilloscope 3, a linear sweep trigger. The local generator signal with the nominal frequency f -Sh Pc (where η is the sample frequency; n 1,2,3, ...) is input to the Schmitt trigger 5, where the square wave is converted to the waveform signal, and then fed to the input of the GSIN 6 The output signal of GSIN 6 is a stepwise varying periodic voltage with a practically unchanged height of each step and with a strictly Constant number of steps {period in a period and the analog input of the analog switch 4 is fed to the signal. with the output of the Schmitt trigger 2, then the output is an analog trunk key 4 pass only those parts of stepwise varying voltage, which in time

The research institutes stepwise varying voltage in a certain constant zone of the oscillogram. As the difference between 10 P-c increases, the rate of change of the image increases. When the sign of this difference changes, the direction of movement of the step-changing voltage changes. A change in the velocity and direction of movement of the stepwise varying voltage is used to determine the sign and magnitude of the divergence of the frequencies to be compared.

The process of frequency comparison using the proposed device is as follows.

Select on the screen some characteristic part of the moving periodic signal, for example, the front of a single pulse, or the amplitude value of one of the periods of the sinusoidal signal or the capacitance mark of one g

From periods, if this voltage Modulates the image by brightness, etc. Constantly following the selected label, for a certain time interval, the magnitude and direction of movement of this label relative to the characteristic point of the reference signal dc (defined by the start of the sweep) is determined. Then, according to the magnitude and direction of the shift, the magnitude and sign of the frequency divergence are calculated.

The proposed device allows the local generator to be tested at the exemplary carrier frequency of radio stations transmitting in pulsed mode, and provides frequency comparisons in the event of a brief disruption of the radio frequency transmission channels. The constant height of each step makes it possible to calculate the number of such steps (and, consequently, the number of periods to be compared

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coincide with pack pulses. Images of these parts of stepwise varying voltages are displayed on the screen of an oscilloscope 3,

Due to the pulse nature of the exemplary frequency source operation, the image on the screen appears periodically.

Since the frequency f in the general case differs from the value of lO-n-f, then with quite frequent reproduction on the screen of a step-wise voltage

cylinders expressed in

The research institutes stepwise varying voltage in a certain constant zone of the oscillogram. As the difference between 10 P-c increases, the rate of change of the image increases. When the sign of this difference changes, the direction of movement of the step-changing voltage changes. A change in the velocity and direction of movement of the stepwise varying voltage is used to determine the sign and magnitude of the divergence of the frequencies to be compared.

The process of frequency comparison using the proposed device is as follows.

Select on the screen some characteristic part of the moving periodic signal, for example, the front of a single pulse, or the amplitude value of one of the periods of the sinusoidal signal or the capacitance mark of one g

From periods, if this voltage Modulates the image by brightness, etc. Constantly following the selected label, the magnitude and direction of movement of this label relative to the characteristic point of the reference signal (defined by the start of the sweep) is determined over a certain time interval. Then, according to the magnitude and direction of the shift, the magnitude and sign of the frequency divergence are calculated.

The proposed device allows the local generator to be tested at the exemplary carrier frequency of radio stations transmitting in pulsed mode, and provides frequency comparisons in the event of a brief disruption of the radio frequency transmission channels. The constant height of each step makes it possible to calculate the number of such steps (and, consequently, the number of periods to be compared

frequencies) if the numbers of the steps passing through the characteristic sweep point at the beginning and end of the disturbance interval of the radio channel are known, and the number of these steps does not exceed the total number of steps in one period of stepwise varying voltage.

Claims (1)

Invention Formula A device for visual comparison of frequencies by radio channel, containing serially connected receiver of exemplary frequency and Schmitt trigger, The channel for generating pulse signals, an oscilloscope, characterized in that, in order to expand the functionality, the channel for the formation of pulse signals, the input of which is an input of the device, is fulfilled in the form of serially connected second Schmitt trigger, a generator of stepwise voltage and voltage. key, the control input of which is connected to the external synchronization input of the oscilloscope and the output of the first IITit trigger, and the output of the key is connected to the signal input (oscilloscope.