SU432463A1 - METHOD OF MEASURING THE VELOCITY OF THE TRANSITIONAL PROCESS OF THE ELECTRIC SYSTEM - Google Patents

Description

one

The invention relates to radio engineering and can be used to measure the difference between the values of the signal under study at the boundary points of a selected time interval in radio engineering, acoustic, geophysical and other pulse systems for various purposes.

There is a known method for measuring the rate of flow of a transient process in an electrical system, based on determining the difference between the values of the output signal at the boundary points of a selected time interval. The known method has a significant disadvantage in that the bandwidth of the amplifier must be large enough for a low-distorted transmission of the signal under study. The extension of the amplifier bandwidth, as is well known, leads to a reduction in the channel noise immunity and a decrease in measurement accuracy. The disadvantages of this method include the need to cut the signal under study at two points of its implementation, which either complicates the equipment by using two parallel gate stages or increases the measurement time by repeating the signal and calculating the difference of the obtained values.

In order to improve the measurement accuracy, the difference in the output signal values is obtained by filtering during the selected time interval the components of the output signal spectrum whose frequencies satisfy the equality:

f - 2 / g - 1 2D

(where, 2, 3, ..., and Dg is the value of the selected time interval), and their summation at the time of the end of the selected time interval.

This method allows to obtain information of interest on the difference in the output values of the transient process at a given time interval by only a single gating of the total response,

i.e. shortens the measurement time.

The drawing shows a block diagram of a device for implementing a method for measuring the speed of a transient process. It contains amplifier 1, filters 2, adder 3,

gating cascade 4 and the recorder 5.

The operation of such a device is as follows.

The signal under study, amplified by amplifier 1, is fed to filters 2, which let

the inputs of the adder 3 signal components,

whose frequencies satisfy equality:

2.-1

fn

2M

At the output of the sum of the matrix 3, a signal is obtained that is proportional to the difference in the values of the signal under study at the boundaries of the selected time interval At. The time stamping is performed by a gating cascade 4, and the measurement result is recorded by a recorder 5 {e.g., a peak voltmeter). According to his testimony, the speed of the transition process is judged.

This sequence of actions is based on the following. At any given moment in time / about the recorded parameter of the process under study in the frequency domain corresponds to a set of instantaneous harmonic components of the instant spectrum, forming a numerical series and representing physical reality that can be observed with the help of appropriate instruments and visually. In the instantaneous spectra there are harmonic components with frequencies that satisfy the equality:

“)„ :: (2 / g-1)

Dg;

where n-, 2, 3,. .. associated with the original function / (/) describing the process under study in the time domain, with the following relation:

  W. T-U () 03 (2 "- 1) -f () dU,

.0

and possessing the property that their sum at the moment of observation turns out to be equal to the half-difference of the values of the initial function, which it takes at the points and, i.e.

R/. (o) - / (+ 0) (fa) -

 V - g / (U) COS (2n - L) - UdU.

JmU 0 J4

In IT, it is assumed that the original function is defined in such a way that, in f (t), Q (passive domain) and / (4-0). The region is called active. The harmonic components of the instantaneous spectrum can be extracted using filters that convolve the input signal with the weighting function:

g (U) cos () U,

too

which can be considered as the impulse response of the passive two-port network with a transient response: /z (.) Jg () (2).

and

Close to it is the transient response of an oscillating circuit LC connected in series with a resistor g: 26

/ Zj (): i - e- “smu o,

about

Where

d

B.

If the LC oscillating circuit is tuned to the frequency of the extracted harmonic a) o

 (2n-1) -, and the time constant of the HS vy4

Q to take large enough to be slightly different from one, then

L, (/) - sin (2 / g-1) A

(2.P - 1) LC

And it differed only by the presence of a constant

multiplier 6 / 0- Thus, as filters, allocating harmonic components of a series to the calculated time / o, the corresponding

Q image tuned resonant circuits. As regards the number of harmonics to be extracted, and, consequently, the required number of filters, this issue should be resolved based on the rate of convergence of the row and the required measurement accuracy. For example, in the practical implementation of the proposed method, to increase the noise immunity of geophysical equipment operating according to the field becoming method, it is sufficient to install two

appropriately configured filters. In this case, the estimated error does not exceed 12%.

Subject invention

A method of measuring the rate of transient electrical system, based on the determination of the difference between the values of the output signal at the boundary points of the selected time interval and division

This difference by the time interval value, characterized in that, in order to increase the measurement accuracy, the difference in the output signal values is obtained by filtering for a selected time interval the components of the output signal spectrum whose frequencies satisfy the equality:

about 1n -

 2D

where, 2, 3,. .., and D / is the value of the selected time interval, and their summation at the time of the end of the selected time interval.

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