SU691783A1 - Apparatus for measuring non-uniformity of amplitude frequency response - Google Patents

Description

(54) DEVICE FOR MEASURING THE UNEVENESSITY OF AMPLITUDE-FREQUENCY CHARACTERISTICS

 I. .

The invention relates to a technique for measuring the amplitude-frequency characteristics (AFC) of two and quadrupoles,.

A meter of amplitude-frequency characteristics is known that contains a modular voltage generator connected in series, a oscillating frequency generator, a quadrupole under study and a logarithm device, an oscillographic indicator, the signal input of which is connected to the output of a logarithmic device, and a horizontal deflection signal input to the generator output modulating voltage series-connected standby multivibrator, control circuit, key scheme, integrating device, computer Arator and reversible counter as well as the source of the reference voltage and the generator of the reference pulses l.

A disadvantage of the known meter is the impossibility of directly measuring the unevenness of the frequency response.

It is also known a device for measuring and reproducing, in particular, an oscillographic, amplitude-frequency characteristic of two or four. lusnpkov, which contains a tunable frequency generator connected in series with the object under study, an amplifier and a detector, a source of supports, voltage, connected through an adjustable divider and through closed contacts of the switch to the measuring device 2

The drawback of the device is the dependence of the measurement result 1a on the instability of the magnitude of the transmission coefficient of the object under study, which leads to ambiguity. The result of the measurement when comparing the frequency characteristics of several objects,

The purpose of the invention is to improve the accuracy and simplify the measurement process.

For this, the amplitude-frequency-irregularity measurement device

characteristics, containing a tunable frequency generator, the input of which is connected to the input terminal, a detector, whose output is connected to the output terminal, an adjustable voltage divider, an amplifier, a key, a voltage source and a measuring device, a memory unit and a subtracting element are inserted, and the output of the unit the signal is connected to the control input of an adjustable voltage divider, the signal input of which is connected to the detector output, and the output is connected to one of the inputs of the subtracting element, the other input of which is The sources of the reference voltage are connected to the output, and the output of the subtracting element is connected directly to the input of the measuring device and, through the series-connected amplifier and CLN, to the input of the memory unit. ; . V -, / / / ....:.

On: The drawing shows a structural electrical circuit of the device for measuring uneven frequency response. g

It contains tunable frequency generator 1, object under study 2, detector 3, adjustable voltage divider 4, subtractive element 5 ,. reference voltage source 6 measuring device 7, amplifier 8, cln 9 and memory unit 1O. The device works as follows. . ...-. ,: -:; -, Measurement of non-uniformity of amplitude; the frequency response of the object under investigation is more than two cycles. In the first measurement cycle, the key 9 is closed. The object under study 2 is supplied from the tunable frequency generator 1 with a constant amplitude voltage Ug.Q with frequency Q, which is taken as; the reference EFI is nominal. Detector 3 detected by the detector Ug | ,, oC of the output of the object under study 2 is measured by level in adjustable divider 4 and subtracted in element 5 from the reference voltage U the reference voltage source b, the difference signal is amplified by the amplifier 8 and through the closed key 9 and the unit memory 10 acts on the control input of an adjustable divider 4, automatically changing the transfer coefficient K. to the last until the voltage at its output becomes equal in BP to the reference voltage

BblXQ-V o- (1)

In the second cycle, the key 9 is open; in the storage unit Yu, the signal proportional to the transmission coefficient Cd of the adjustable divider 4 (in the first cycle) is memorized. On the object under study 2, the tunable frequency 1 is supplied from Ienertor with the voltage of one of the controlled frequencies Ug UBHO ® ™. The signal and at the input of the measuring device 7 can be represented by the expression

 D-O and-ivyh

(2)

In view of expression (1), we obtain in Yoida

,, ,, l

t1 ollj)

H out /

or

DK

(3)

that is, the signal at the output of the subtracting element 5, the incoming Hai measuring device 7, is proportional to the relative non-uniformity of the amplitude-frequency characteristic of the object under study 2. Formulatizing device a detector whose input is connected to the upstream terminal, an adjustable voltage divider, an amplifier, a switch, a reference voltage source and a measuring device This is so that, in order to improve accuracy and simplify the measurement process, a memory unit, a readout element is inserted into it, with this output of the memory unit connected to the control input of the variable voltage divider, the signal input which is connected to the detector output, and the output is connected to one of the inputs of the readout element, the other input of which is connected to the output source of the reference voltage, and the output of the connecting element directly to the input of the Measuring device and through the successor on the connected amplifier and the key - to the input of storage unit. Sources of information taken into account during the examination 601 7836 1. USSR author's certificate No. 476521, cl. Q 01 R 27/28, O5.07.75. 2. The patent of Germany Nb 13О38И, 5 cl. 21 e 27/30, 04.01.73.