SU1619198A1 - Device for measuring modulus of gain ratio of four-terminal networks - Google Patents

Abstract

The invention relates to a radio measuring technique. The purpose of the invention is to improve the measurement accuracy by introducing into the device an amplitude detector 3, a DC amplifier 4, a logarithmic converter 8, a decoder 11 and a block of 7 n two-input elements I. The device also contains 1 signal generator, analog-to-digital converter 6, register 9 and control units 5, subtraction 10 and indications 12, 1, or 2.

Description

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about with

This invention relates to a radio metering technique and is intended to measure a four-terminal transmission coefficient module.

The aim of the invention is to increase the measurement accuracy.

The drawing shows a block diagram of a device for measuring the modulus of the transmission coefficient of four

POLES.

A device for measuring the quadrupole transmission coefficient module contains a signal generator 1, a quadrupole 2 under study, an amplitude detector 3, a DC amplifier 4, a control unit 5, an analog-to-digital converter 6, a block 7 of two input elements And, a logarithm converter 8, n - bit register 9, subtraction unit 10, decoder 11 and display unit 12.

The output of the signal generator 1 is connected to the input of the four-pole 2 under study, the output of which is connected to the input of the amplitude detector 3, the output of which is connected to the input of the DC amplifier 4, the output of which is connected to the input of the analog-digital converter 6, the output of which is connected to the input logarithmic converter 8, the output of which is connected to the first input of the decremented subtraction unit 10 and the first input of the block 7 n two-input elements And, the second input of which is connected to the output of the control unit 5, and the output to the input -bit register 9, the output of which is connected to the second input (subtrahend) subtracting unit 10. The output of the subtraction unit 10 is connected to the input of the decoder 11, the output of which is connected to the (pN) -discharge unit 12 of the display of the result in digital form with a sign bit. Each of the output bits of the logarithmic converter 8 is connected to the first input of each of the two-input logic elements H (first input of block 7), the second inputs of which are combined and represent the second input of block 7, the outputs n of the two-input elements And represent the output of block 7.

A device for measuring the modulus of the transfer coefficient of a four-pole operates as follows.

In the calibration mode, which is set from the control side 5, to block 7

,,

five

to

thirty

ps.,

40

50

n two-input elements AND; a resolution level is supplied for recording information from the output of a logarithmic trans- generator 8 to register 9. At the same time, the signal from generator 1, the passage through the quadrupole 2 under study, whose magnitude of the transmission coefficient is set to one or in decibels, zero decibels (or excluded from the circuit, and the output of generator 1 is connected to the input of the amplitude detector 3), detected by the amplitude detector 3. The detected voltage, which is the input voltage of the quadrupole, is amplified and smoothed by the direct current amplifier 4 and converted by the analog converter 6 into a pair the allelic binary-decimal code, and then the logarithmic converter 8 is transformed according to the law of the decimal logarithm, and here it is multiplied by a constant factor 20. The result goes to the first input of the decremented subtraction unit 10 and simultaneously writes to the 9S register from the input of which goes to the second input (subtracted) block 10 subtraction. The difference of two identical numbers is zero, which is decrypted and displayed by the result indication unit 12 in the form: 0 ... 0; 0 ... 0 decibels. In this way, the presetting for zero values is eliminated. In the measurement mode, which is set by control block 5, block 7 of the two-element elements is supplied to AND, the course is prohibited, which prohibits writing information to the register 9. On the studied quadrupole 2, a measured transfer coefficient module or quadranct 2 is set is switched off, it is turned on between generator 1 and amplitude detector 3. The output voltage of the quadrupole 2 is transformed as in the calibration mode, the input voltage of the quadrupole 2, post goes to the first input of the (decremented) subtraction unit 10.

The output of block 10 subtraction Formed the result of subtraction

s.,

55

(Sign |. (2018atvykh- 201gUmB,)

(Um x

 Sign

201g

which is the value of the modulus kg transmission efficiency quadrupolar

5. 161

2, expressed in decibels. The digital result code is fed through the decoder 11 to the display unit 12, where it is displayed in decimal code in decibels and with a sign corresponding to what is measured - attenuation or gain.

The use of the logarithmic ratio method and the elimination of systematic error arising due to the imperfection of the shielding of the high-frequency path, reduces the maximum measurement error by a factor of 2 to 3.

Claims (1)

Invention Formula A device for measuring a quadrupole transmission coefficient module, comprising a signal generator, the output of which is connected to terminals for connecting a quadrupole input, an analog-to-digital converter, a register, a subtraction unit, a control unit, a display unit, and terminals connecting a quadrupole output is characterized in that, in order to improve measurement accuracy, a series-connected amplitude detector and a direct current amplifier, a logarithmic converter, a decoder and a block n of two-input elements, are inputted into it, the terminals for connecting the four-pole output are connected to the input of the amplitude detector, output which through a DC amplifier and analog-to-digital converter is connected to the input of a logarithmic converter, the output of which is connected to the first input The subtractor unit and the first input unit n of the two-input elements I, the second input of which is connected to the output of the control unit, and the output to the input of the register, the output of which is connected to the second input of the subtraction unit, the output of which through the decoder is connected to the input of the display unit.