SU840923A1 - Device for determining autouorellation functions of transient characteristics of surface acoustic wave-based filters - Google Patents

Description

The invention relates to specialized tools calculator. This technique can be used to solve problems of automatic control, identification, filtering, in particular in piezotechnics, nanosecond technology.

Known correlator of signals ’pulse generators containing a reference signal generator, a signal generator and a series-connected multiplication unit, an integrator and an indicator. A stroboscopic generator is introduced into the correlator, the outputs of which are connected, respectively, to the synchronizing inputs of the model and test signal generator, and the outputs of these generators are connected to the corresponding inputs of the multiplication unit. j

The known device essentially solves the control problem fl}.

However, the class of the studied processes cannot be extended to the frequency range up to 1 Hz due to the difficulty -,. mi implementations of the multiplication block.

Known correlator based on measuring the average value of the module of the difference between the direct and delayed signals, containing an amplifier, detector, integrator, display unit and a rectangular pulse generator.

A disadvantage of the known device is associated with the need for a delay unit, which complicates the correlator.

The purpose of the invention is to simplify the device when receiving the autocorrelation function (ACF) of the transition characteristics (objects) of filters on acoustic surface waves (AR) due to the exclusion of the delay unit.

This goal is achieved in that in a device for determining the autocorrelation functions of the transient characteristics of filters on acoustic surface waves, containing a rectangular pulse generator, the output of which is connected to the input of the filter under investigation, the output of which is connected through the amplifier to the input of the detector, the integrator, the output of which is connected to the information _{s to the} input of the display unit, a key, a time interval meter and a counter are entered, the counting input of which is connected to the output of the rectangular generator pulses, the installation input of the counter is combined with the reset input of the integrator and connected to the output of the display unit, the output of the counter is connected to the first input of the time interval meter, to the control 15 inputs of the rectangular pulse generator, display unit and key, the information input of which is connected to the detector output, and the output is connected to the integrator input, the second input of the time interval meter is connected to the output of the rectangular pulse generator.

. The proposed device is presented in the drawing. 25

The device consists of a generator 1 of rectangular pulses with a variable duration, the output of which is output to a filter ΑΙΊΒ 2, to the output of the time interval meter 3 and to the first ³⁰ counter input 4.

The AR filter 2 under investigation is connected through an amplifier 5 to a detector 6 connected to the first input of the key 7.

The output of the key 7 is connected to the information input ^{35 of the} integrator 8, which is connected to the first input of the display unit 9, with the input of the generator 1, with the second input of the meter 3 time intervals, with the output and the second input ^{4 (3} counters 4.

The integrator 8 is connected to the information input of the indication 9, the reset input of the integrator is connected to the output of the indication unit 9. ⁴⁵

A device for automatically determining the ACF transient characteristics of the filters on the reclosure works as follows.

The output pulses of the generator 1 po- tread ⁵⁰ to the input of the test filter reclosure, the counter 4 and the meter 3. The response output 'object amplified by the amplifier 5 is detected by the detector, f -> about 55 and via switch 7 to the input 8 of the integrator with reset. As soon as the counter accumulates the number of pulses multiple of 10, for example 1000, a signal will appear on its output. This signal, acting on the key 7, prohibits the further passage of radio pulses to the integrator and starts the display unit 9, which is, for example, a digital voltmeter that measures the ordinate of the ACF. While the ordinate of the ACF is being measured, the signal from the counter, acting on the generator 1, forces it to change the duration of the generated rectangular pulses by the value A'C ', and acting on the second input of the time interval meter, stops the procedure for measuring the duration of rectangular pulses. As soon as the ordinate of the ACF is measured, the reset signal is suppressed at the input of the display unit 9, which the integrator will reset and reset the counter. The result of zeroing is opening the key. The counter begins to count the number of perturbing rectangular pulses, and meter 3 measures their duration, which is equal to Cc + D'C '). The cycle repeats, but the next ordinate of the ACF has already been determined.

Note that the rectangular pulse at the output of the generator can be represented by the expression f (t) = 1 (t) -1 (t + At) (1) where 1 (t) is the unit function

At the output of the object, the difference of the two transients shifted by Δ ^{ί =,} 6+ Αΐ ”<

Given (1) the response of the filter to a rectangular pulse, detection and averaging, the generator output signal can be represented as

The described device allows you to determine the ACF transient characteristics of the filters on the automatic reclosure with an amplitude resolution of 50 dB.

The determination time of one ordinate of the ACF is 0.1 s, while the measurement accuracy of more than 1 · достигается is achieved.

Claims (2)

1. USSR author's certificate No. 602951, cl. G 06 F 15/34, 1977. 2. Zhovinsky V.N., Arkhovsky V.F. Correlation device. M., Energie. 1974. with. 35-36.