SU731377A1 - Device for measuring duration of front of shock acceleration pulses - Google Patents

Description

one

The invention relates to the field of measurement technology and is intended to measure the duration of a pulse front. shock acceleration.

The duration of the acceleration pulse pulse, defined as the time interval from the moment of occurrence of the shock wave to the moment corresponding to its peak value, is an important parameter of the mechanical shock processes, which can be used to estimate the accuracy of accelerometer calibration.

A device for measuring the duration of the shock pulse acceleration front is known, which contains a matching device, a differentiator, a limiting amplifier, a linear-varying voltage generator, a fadron circuit, a device for recording the measurement result in digital form using an electromechanical counter and a trigger. All elements, except the trigger, are interconnected in series. The trigger input is connected to the output of the amplifier-limiter, and the output to the matching device 1.

This device does not allow to measure the duration of the shock acceleration pulse front with superimposed oscillations. This is due to the fact that in the case of impulses with superimposed oscillations with the help of elements of a known device, it is impossible to implement the necessary signal transformations for the recording of the 5th device.

The purpose of the invention is to increase the accuracy of measuring the duration of the shock pulse front accelerated;: arbitrary shape.

10 This goal is achieved by the fact that the device is equipped with an amplitude-time converter and a Schmidt trigger, and the output of the matching device is connected to the input of the limiting amplifier via

15 amplitude-time converter and generator of linear-varying voltage to Schmidt trigger, the output of which is connected to the second input of the trigger, the first input of which is connected to the output

20 amplifier-limiter, and the output - to the recording device.

FIG. 1 shows a block diagram of the device; in fig. 2, a-e shows diagrams explaining the operation of the device.

25 The device contains a matching device 1, an amplitude-time converter 2, a generator of Li-changing (sawtooth) voltage, a Schmidt trigger 4, an amplifier-limiter 5, a trigger 30 ger 6 and a recording device 7.

In the proposed device, the input of the matching device 1 is connected to the measuring converter of shock accelerations, and the output is connected to the input of the amplitude-time converter 2 and to the input of the amplifier-limiter 5. The amplitude-time converter 2, the generator 3 linearly varying voltage and Schmidt trigger 4 are connected in series. One input of the trigger 6 is connected to the output of the amplifier-limiter 5, and the second - with the output of the Schmidt trigger 4. The output of the trigger 6 is connected to the input of the recording device 7.

The device works as follows.

The impulse voltage (Fig. 2a) is fed to the input of the matching device 1 from the output of the piezoelectric impact acceleration transducer. From the output of the matching device 1, the signal is fed to the limiting amplifier 5 and to the amplitude-time converter 2. A rectangular impulse from the output of the limiting amplifier 5 triggers trigger 6. In accordance with the voltage form (Fig. 2, b) on the memory capacitor the amplitude-time converter 2 at the output of the same converter has a sequence of rectangular pulses shown in FIG. 2, c. These pulses trigger the generator 3 linearly varying voltage, the amplitude of the output voltage of which (Fig. 2, d) is proportional to the duration of the output pulses of the amplitude-time converter 2 (Fig. 2, c).

The Schmidt trigger 4 is adjusted so that its triggering level is equal to (or slightly higher) the value of Ots (Fig. 2, c, d). As a result, at the output of the Schmidt trigger 4, a rectangular pulse is obtained (Fig. 2, d), which is shifted relative to the beginning of the measured pulse by time TF + Ti, i.e., greater than the duration of the front TF of the measured pulse. This impulse triggers trigger 6, the output of which

a rectangular impulse of duration t Tf-Lt is formed, i.e., a value t greater than the length of the leading edge of the measured impulse. Next, from the output of the flip-flop 6pr, a rectangular pulse (Fig. 2, e) is fed to the recording device 7, the readout system of which memorizes the time mr-fT. When calibrating the instrument systematically

the error t can be eliminated and, thus, its readings will correspond to the length of the leading edge of the measured pulse.

The device allows you to measure the duration

the front of the shock acceleration pulses of both a simple form (Fig. 2, a - dotted line) and the duration of the front of pulses with superimposed oscillations (Fig. 2, a - a continuous line).

Claims (1)

Invention Formula A device for measuring the duration of a shock acceleration pulse containing a matching device, an amplifier-limiter, a trigger, a linear-varying voltage generator and a recording device, characterized in that measuring the duration of the front of an arbitrary pulse acceleration pulse, the amplitude-time converter and the Schmidt trigger are introduced, the output of the matching device is connected to the input of the limiting amplifier, and through the amplitude-time converter and the generator of linear-varying loading to the Schmidt trigger, the output of which is connected to second trigger input, first input which is connected to the output of the amplifier limiter, and the output - to the recording device. Sources of information irinty taken into account in the examination 1- Subbotin M. I. A device for measuring shock accelerations, PNT and software, 1962, topic 31 No. P-62-18 / 4 (prototype). a p1