SU1293495A2 - Device for measuring logarithmic decrement - Google Patents

Abstract

The invention relates to a measurement technique and can be used to study the physical properties of various objects. The aim of the invention is to increase the efficiency of the measurement process by automatically setting threshold voltages of a two-threshold discriminator. The device contains a sensor 1, an amplifier 2, a divider 3, a peak detector 4, a divider 5, an amplifier 6 with variable gain, a two-threshold discriminator 7, a counter 8, a block 9 of circuits And, a block 10 of registration, a program register 11, the first pulse shaper 12 , inhibit circuit 13, delay circuit 14, trigger 15, the second pulse generator 16. The logarithmic decrement of attenuation of the oscillations under study is determined from IT0 and POR (,, R = 6 1n, where N and POR are the number of periods of the input signal, when its amplitude U is between the pores by means of the introduction of the automatic installation of the threshold threshold voltage setting Upopi, the porg, consisting of amplifier 2, dividers 3.5, detector 4, allows the device to remove the dependence of the logarithmic decrement on the oscillation amplitude during one damped oscillatory process without initial setting of the threshold voltage values when replacing the sample under study or when changing the amplitude of oscillations, which increases the speed of the device. silt AT

Description

The invention relates to a measuring technique, can be used to study the physical properties of various objects, and is an improvement to the basic author. No. 474696. The purpose of the invention is to increase the speed of the measurement process by automatically generating threshold voltages determining the controlled range of variation of the amplitude of the oscillation under study.

The drawing shows a block diagram of the device.

The device comprises a sensor, the output of which is connected to the input of the block for the formation of threshold voltages j consisting of amplifier 2, divider 3j of peak detector 4 and second divider 5 connected; after -significantly among themselves. The output of the sensor is also connected to the input of the amplifier 6 with a variable gain. The output of amplifier 6 is connected to the first input of the two-threshold discriminator 7, the second and third inputs of which are connected respectively to the outputs of the peak detector 4 and divider 5. The output of the two-threshold discriminator 7 is connected to the input of the counter 8, the output of which is connected to the first input of block 9 of the circuits And, and the output of block 9 of the circuits And is connected to the block 10 of the registration. The output of the software register 1 is connected to the amplifier 6 and to the second input of the block 9 of the circuits I. The input of the first pulse shaper 2 is connected to the output of the amplifier 6, and its output is connected to the first input of the inhibit circuit 13, the second input of this circuit is connected to the output of the discriminator 7. The output delay circuit 14 with the reset input of the counter 8 and with the input of the software register 11. The trigger input 15 is connected to the discriminator 7 output, and the output to the second pulse driver 16, the output of which is connected to the delay circuit input and the reset input of the 9 I. Trigg The ep 15 is transferred to another state by pulses from the output of the prohibition circuit 13.

The device works as follows

In the initial state, the gain factor of amplifier 6 is minimal and is set by the signal arriving at its

five

0

five

0

0

five

0

five

the first control input from the output of the first bit of software register 11 (counter 8 and trigger 15 are reset to O). After the oscillations of the sample are excited, the electrical signal from the output of sensor 1 begins to flow through amplifier 2 to divider 3j which, together with peak detector 4, which rectifies the electric signal, forms a threshold voltage UPQP,. Divider 5 forms the threshold voltage Uf, op. . These threshold voltages are applied to discriminator 7.

The electrical signal from the sensor also enters through the amplifier 6 to the input of the discriminator 7 and through the driver 12 and the prohibition circuit 13 to the reset input of trigger 15. Since the trigger is reset to O, its state will not change. When the amplitude of the 11K signal is reduced to a value, pulses begin to appear at the output of the discriminator 7, which are considered to be counter 8 and fed to the control input of the inhibitor circuit 13, prohibiting the arrival of pulses from the driver 12 to the trigger reset input. In addition, these pulses are fed to the record 1 input of this trigger, the first of which is transferred to state 1. When the amplitude of the input signal of the discriminator 7 compares;

with CO value U

since then 2

arrival

pulses from the discriminator are terminated. The counter 8 will calculate the number of periods of the input signal N, the amplitudes of which Ug are between threshold voltages.

Unop., UB ,,, 6 Unop ..

The logarithmic damping decrement of the studied oscillations is determined from the equation

§ 1 j, U101M N Unop. 2

After the output pulses of the discriminator 7 stop, the reset input of the trigger 15 again starts to receive pulses from the prohibition circuit 13, the first of which is flip-flop to the state O, and the driver 16 generates a pulse arriving at the input of the block 9 of the circuit I. Since The second input of this block is given signals from

the corresponding bit outputs of the program register and the counter, the measurement number is input to the input of the registration unit 10, and the number N is recorded therein. The output pulse of the imaging unit 16, in addition, enters through the delay circuit 14 to the reset input of the counter 8, sets its initial state, and to the input of the movement of the program register 11, the movement 1 from the first register to the second. The output of the second bit of the register, which arrives at the corresponding control input of the amplifier 6, changes its gain so that

and.

K.2 Unop.,

input amplitude

amplifier;

new gain factor.

as soon as the amplitude entered the discriminator compare Editor M.Tovtin Order 372/42

Compiled by A. Sharovatov

Tehred M. Hodankch M. Samborska Proofreader

Circulation 5UOsigned

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

1293495

with with

Unop.i from the output of the discriminator appears pulses and the process proceeds as described.

Claims (1)

Invention Formula A device for measuring the logarithmic decrement of oscillation damping according to auth.St. No. 474696, characterized in that ,. in order to increase speed by automatically setting threshold voltages of a two-threshold discriminator, it is equipped with a threshold voltage shaping unit consisting of an amplifier, two voltage dividers and a peak detector, the amplifier input is connected to the sensor, the output of the amplifier is connected to the input through the first voltage divider peak detector and peak detector output connected to the first input of the two-threshold fSfiCK- and through the second voltage divider to the second input of the two-threshold discriminator.