SU1405122A1 - Device for measuring logarithmic attenuation decrement - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to increase the measurement accuracy. The device contains a trigger (T) 1, electronic keys (eq) 2 and 13, amplifier-shaper 3, differential. circuit 4, counter (C) 5 pulses, amplitude detectors 6 and 7, block 8 logarithmization, block 12 registration. An amplifier 9, a sampling and storage unit 10, an adder 11, EC 14 are input. At the 1st input T1 a pulse signal is received, the leading edge of which sets T1 to the state that at its 1st 2nd outputs permitting and inhibiting potentials are established, under which the EC 2 and 14 are closed. The amplifier 9 operates in a voltage repeater mode. Block 10 samples the value of the logarithm of the children voltage. Torah 7 and the subsequent storage of this level during the time T.Logarifmich. the damping factor is changed by the box 12.EC13 is disconnected. The signal of the impulse transition function io (t) passes through EC2 to amplifier 3, which forms from the pos. and neg. signal half-wave pulses are similar in shape to rectangular. A series of short pulses is generated at the C 5 output. From 5, T 1 is thrown as soon as the passing of the pos. and neg. half wave EC 13 closes, EC 2 and 14 opens. Amplifier 9 is in inverted mode. 1 il. (L

Description

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The invention relates to measurement technology, automation and can {Be used in any industry where measurement of the 5 decay of structures is required.

The purpose of the invention is to improve the measurement accuracy,

The drawing shows a structural electrical circuit of the proposed device.

A device for measuring the logarithmic decrement of flouser contains trigger 1, first electronic switch 2, amplifier shaper 3, differential circuit 4, pulse counter 5, first 6 and second 7 amplitude detectors, logarithm unit 8, amplifier 9, sampling unit 10 and storage, the adder 11, block 12 registration About the second 13 and third 14 electronic keys.

The device works as follows

I at once.

I At the first input of trigger 1 is input (I W is an input pulse signal), whose leading edge sets trigger 1 to such a state that its first and second outputs are set, respectively, to enabling inhibitory Q potentials, under the action of which the first 2 and the third 14 electronic switches are closed, the amplifier 9 operates in the voltage repeater mode, the sampling unit 10 and the I storage selects the logarithm of the voltage from the output I of the second amplitude detector 7 and I then stores this level for Yemeni T, measurement of the logarithmic decrement Registering unit 12, and a second electronic switch 13 is opened. The signal of the pulse transition function co (t), represented as a voltage, passes through the first electronic switch 2 to the input of the amplifier-former 3, which forms pulses from the positive and negative half-waves of the signal of the pulsed transition characteristic mogonnym.

The differentiating circuit 4 differentiates 3 pulses arriving at its input from the output of the amplifier-former, resulting in a series of short pulses at the input of the counter 5 pulses.

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5 o

five

0 5 0 5 O

pulses. Pulse counter 5 flips trigger 1 as soon as the passage of the positive and negative half-waves of the pulse transient function signal ends. As a result, the second electronic switch 13 closes, and the first 2 and second 14 electronic switches are opened, the amplifier 9 operates in voltage inversion mode, and the sampling and storage unit 10 transfers the logarithm value from the output of the second amplitude detector 7 to the second adder 11, the first input of which receives the value of the logarithm of the voltage - from the output of the first amplitude detector 6. As a result, the output of the adder 11 has a signal and, equal to the difference of the logarithms of the voltages from the outputs of the first 6 and second 7 amplitude detectors, which is fed to the input of the registration unit 12, i.e. the output of the adder 11 has a signal equal to

and, 1pi, - 1pi, 1pu1ch

those. logarithmic decrement, decay.

Claims (1)

Formula invented and A device for measuring the logarithmic damping decrement containing a trigger, the first input of which is an input of a pulse signal, serially connected a first electronic switch, the control input of which is connected to the first output of the trigger, amplifier j, tel, differentiating circuit and pulse counter,. the output of which is connected to the second trigger input, the second electronic key, the control input of which is connected to the second trigger output, the registration unit, the first and second amplitude detectors, cat inputs connected to the output of the first electronic key, whose information input is the input of a pulse transient function, the output of the first amplitude detector is connected to the first signal input of the second electronic key, a logarithm block, characterized in that, in order to improve the measurement accuracy, a third electronic key is entered signal input and 314051 the output of which is connected respectively to the output of the second amplitude detector and the input of the logarithm block, serially connected amplifier, the signal input of which is connected to the output of the logarithm block, the sample and hold block and the adder, the output of which is connected to the second signal input of the second 1Q 22 The electronic key, the first and second signal outputs of which are connected respectively to the input of the registration unit and the input of the logarithm block, the amplifier output is connected to the second input of the adder, the first trigger output is connected to the control inputs of the third electronic key, amplifier and the sample and storage unit.