SU781711A1 - Automatic four-detector meter of complex parameters - Google Patents

Description

(54) AUTOMATIC FOUR-DETECTOR METER OF COMPLEX PARAMETERS

This invention relates to a radio metering technique and may be used. . It is used to measure the impedances and complex transfer coefficients of electrical signal transducers, as well as to measure the amplitude-phase-frequency characteristics of mechanical signal transducers in the low- and infra-low frequency bands.

An analog meter for quadrupole complex transfer coefficient is known, which contains a reference generator and a multiplying device on operational amplifiers, equipped with thermal converters, an amplitude detector, magnetoelectric logometers and a switch, and the thermal converters are connected to the outputs of operational amplifiers, and their thermocouples connected pairwise and counter, connected to the inputs of differential amplifiers, the output of each of which through 25 low-pass filter connects ene with one of the windings magnetoelectric ratiometer and the input amplitude detector connected to the reference input of the unit and its output -c heater

A thermocouple transducer whose thermocouple is connected via an amplifier with the second windings of the magnetoelectric logometers and through a switch to the converter heater I.

The disadvantages of the meter. the non-automatic nature of the measurements, which leads to the need for additional calculations to determine the module and phase of the complex four-port transmission coefficients, limited functionality, which makes it impossible to measure impedances of two-pole networks, the relative complexity of the design and the long measurement time at infra-low frequencies, determined by constant nnoy lowpass filters.

The closest technical solution to this invention is em-. with automatic chip detector of complex parameters of the microwave path, contents tunable frequency generator, bridge measuring unit, phase-shifting units based on double waveguide tees and WAVEGUIDE segments, four adders of the reference and measured signals, four detector quadrs, four low-pass filters, two differential amplifier and electron-beam indicator 2.

The disadvantages of this device are a large measurement time in the low and infra-low frequency range, determined by the constant time of the low-pass filters of detection boxes, a small overlap of the frequency range not exceeding 10, determined by the properties of phase-shifting chains, the complexity of the circuit and design.

The purpose of the invention is to increase the speed and increase the broadband range of low and infra-low frequencies.

The goal is achieved by the fact that the automatic four-detector measuring instrument of complex parameters contains a tunable frequency generator, the first output of which is connected to the input of the measuring unit, the output of which is connected to the measurement inputs of four adders, the outputs of which are connected respectively to four quad detectors, electron beam indicator , two differential amplifiers, the outputs of which are connected respectively with two deflecting plates of the electron-beam indicator a, four blocks of storing amplitude values of signals with memory dumping are introduced, the inputs of which are connected to the outputs of four quad detectors, and the outputs are connected to the inputs of two differential amplifiers, four additional outputs of the tunable frequency generator are connected respectively to the reference inputs of four adders.

 The drawing shows a block diagram of the device in the mode of measuring the complex reflection coefficients of two-terminal networks (impedances

The device contains a tunable frequency generator 1, for example of type Gb-26, with main output 2 and additional outputs 3-6, a measuring unit 7 of bridge type with a two-half alarm 8 under investigation, adders 9-12 quad detectors 13-16, blocks 1720 for storing amplitude Signals values with automatic or manual memory reset, differential amplifiers 21 and 22, electron beam indicator 23.

The device works as follows. .

The signal of the U sinuut type (UQ -, amplitude, C) is the circular frequency, t is the time) from the main output 2 of the generator 1 is fed to the bridge measuring unit 7 with the two-terminal device under study 8. With the output of the measuring unit .7 the signal is

 sin tot + if),

where k is the transmission coefficient of the measuring unit 7; p is the modulus of the reflection coefficient of the two-port 8 under study;

H is the phase of the reflection coefficient of the two-port 8 under study,

arrives at the measuring inputs of adders 9-12.

With additional outputs 3-6 gene {) ator 1 tunable frequency with phase 0 °, 90 °, 180 °, are sent to the reference outputs of adders 9-12 signals of the form

UQ S i nvwt,

90 °),

and s i n (cyt + 180 °)

i n (oyt

% 270) i n (isrt o

Voltages arriving at the inputs of quadrants 13-16 have ID

Ug, k i n ((Ot + 4) + k, UoS i nuwt,

.1.rl ./.-. Ti.

UQ s i n (“ut + q) +

and

g

6Xl4

+ k2, UoSin (uDt + 180 °),

0

(sh. t | m) +

ik pUpSin (u TjUpSinCuot +).

B) (16 (“+)

k Ugsin (uut + 2700), de k is the transfer coefficient of the adder for the measured signal;

k is the transfer coefficient of the adder for the reference signal.

You can take kj k, k, and k 1

At the outputs of quad detectors, 13-16 voltage amplitudes are described by the expressions j

U5, .. ,,., Kn Uo (1 P: J2fcosЧ), Cx; с№ (, - 2pcos.), iVa5 k | kAUMHfV2psin4) (UJ) - 2psin4), 0 gDb l, the signal transfer coefficient of the detector-quad. Similar expressions describe constant voltages that occur at the outputs of blocks 17-20 for storing the amplitude values of the signals.

As a result of the pairwise subtraction of these constant stresses by differential forces, we obtain

 Y.YosCh,

 kj k k ujiipsin, where ku is the gain of the differential amplifier.

After giving the signals (i tssh and Uo, tt ,, “on the electron beam indicator.

torus 23 we get a light spot on the screen, the radius of deviation of which from the center of the tube R characterizes the modulus of the reflection coefficient, and the angle of deviation of the radius vector from the vertical V

phase reflection coefficient

1 TO

11Vs 21) with cVM% f

where k is the indicator sensitivity

H and GS to and meas --- tg. and

This automatic complex parameter meter provides measurements at infrared frequencies over a time period of no more than one signal period in a wide frequency range. Resetting the memory allows repeated measurements.

Using this device, one can also measure the complex transmission coefficients of electrical signal transducers (two-port networks), as well as the complex transmission coefficients of mechanical signal transducers (seismic receivers, microphones, hydrophones, etc.), only the constructive performance of the measuring unit 7.

Claims (2)

1. USSR author's certificate  432427, cl. G 01 R 29/00, 10.02.72. 2. Bondarenko I.K., Deinega G.A., 5 Magrachev Z.V. Automation of measurements, parameters of microwave paths. M., Soviet Radio, 1969, p. 24-26 (prototype).