SU1732156A1 - Method of identifying time moments in parallel recording of parameters of one or more processes - Google Patents

Abstract

The method allows to increase the accuracy of the identification of points in time when registering parameters of fast processes. Before starting the registration of parameters of one or several processes, an external light is applied to the photo recorder carrier, a photodetector is installed in the same place, and the synchronizing signals are formed by the photoreceiver at the time of registration of the process image. 2 Il.

Description

The invention relates to a measurement technique and can be used in parallel recording of parameters of one or several processes.

The invention can be most effectively used in photographic registration of fast processes (fast burning, explosion, propagation of shock waves, spark discharge, high-temperature plasma, etc.) in parallel with their other parameters (electrical, thermodynamic, etc.).

A known method of identifying time points during the registration of measured values, including the simultaneous supply of clock pulses to recorders. This method consists in the fact that with the help of an external generator during the flow

The process serves clock pulses to all recorders j.

The disadvantages of this method are the need for strict temporary reference of the moment of issuing the clock pulses and the start of recording the parameters of the processes under study, reducing the identification accuracy K, which is determined by the expression

TO

l

p SS

(one)

Where

Wed - the duration of registration

parameters;

/ l

Lc - the duration of the issuance of the synchronizing signal, with an increase in the temporal sweep rate of the parameters by the registrars due to the shortening of the time for studying the processes.

31732156

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The essence of the invention is a method for identifying points in time with simultaneous registration of measured values by several registrars 2J.

The known method consists in the fact that when parallel variables are registered by several recorders in order to increase the accuracy of identification using an external device, a sequence of sync pulses, which are random functions of time, are sent to all recorders.

The disadvantages of this method are the need for external equipment with respect to the complex, which serves to carry out the required studies, a clock generator, the difficulty of generating several distinct clock pulses and supplying them to all recorders in a short time when examining fast processes, the accuracy of identification depends on the time sweep rate. parameters by registrars, the inability to conduct a temporary identification of all parameters, if at least one of the registries Athor has neelektroizmeritelnuyu nature.

Thus, the known method does not provide a constant identification accuracy and does not allow the identification of a wide class of non-uniform parameters, which will generally affect the reliability of the identification method.

The aim of the invention is to increase the reliability of the identification of points in time when registering the parameters of fast processes.

This goal is achieved by the fact that before starting the registration of parameters of one or several processes using an external light radiation, a label is placed on the carrier of the photo recorder, a photodetector is installed at the place of marking, and the synchronizing signals are formed by the photoreceiver at the time of recording the process image.

Fig L shows a diagram of the implementation of the method; Figure 2 shows the discharge current waveform and optical picture.

The method is carried out as follows.

Prior to the process of photographing the process, external light is applied by radiating through a narrow slit, a label within the frame window at the upper edge of the film located in the focal plane.

0 photo recorder. At the moment of time corresponding to the beginning of the registration of the optical pattern within the translucent slit, a light pulse appears from which the photodetector5 forms a synchronizing signal supplied to the other recorders.

Consequently, the correspondence of identification marks on all the recorders to one moment in time is the result of the method for generating a synchronizing signal, i.e. the consequence of the fact that the geometrical location of the points of the mark and the location of the photodetector on the focal plane of the photographic recorder coincide.

one

Example. Investigation of the process of radial development of the radiating

0 a spark discharge channel is produced by recording its optical pictures using an ultrafast photographic recorder (SFR) and electrical parameters (current and voltage) on dual-beam oscilloscopes. The SFR 0 camera lens builds an image of the light source in the plane of the rotating mirror Z, which transfers the obtained image to the focal plane of the device T, on which the film is located (figure 1). In the focal frame of the SFR camera, a narrow slit is made in which the light guide is installed. Before the photo registration is started, the external light radiation transmitted through the fiber is applied through the slit through, the mark on the film. Then the free end of the fiber is supplied to the photocathode of the PMT. The synchronization signal, which forms the photomultiplier at the time of photo registration within the slit, is transmitted from the anode circuit of the photomultiplier to oscillographs, and identification marks appear on them. Figure 2 presents: a) an oscillogram of the discharge current with an identification mark on the lower beam, which is the moment of register 5

0

five

image process in the field of the label M;

about; optical picture of the expanding channel of the spark with the mark M applied before the start of the photo registration.

By combining the marks on the optical picture and on the lower beam of the oscilloscope, the time values of I (t) and r (t) are identified in time.

Thus, the accuracy of identification is determined only by the ratio of the geometric dimensions of the slit and the frame window of the photographic recorder and does not depend on the speed of its scanning. Indeed, the duration of the recorded signal

tn

V)

1 p length

(2)

frame window

v

R

- temporal sweep rate of the parameter by the recorder. The duration of the issuance of the clock signal is determined by the expression

Ј --- P

v.

(3)

where is ah

- width translucent

slots.

Taking into account formulas (2) and (3) for accuracy of identification, we have

-R-Јs

ep

) x y

1 Lx

1 - - t

(four)

those. K does not depend on the speed of the time base.

Reliability, constancy of accuracy, and in general, the high reliability of the proposed method of identification is determined by the fact that the formation of a synchronizing pulse (at the right time) is due only to the functioning of the process under study.

five

five

0

five

0

five

In addition, the method allows identification of non-uniform parameters in time, for example, electrical parameters with optical or thermodynamic, etc. This advantage of the method is the result of the possibility of choosing a registrar on which one of the identification marks is put before the registration begins. As a rule, a registrar is chosen as such on which during its operation the marking of a mark by a synchronizing signal is difficult or impossible.

Increasing the reliability of identification using this method allows to increase the service life of the instrumentation complex and reduce energy consumption, since this significantly reduces the number of duplicate measurements necessary to achieve a given identification accuracy. It has been established experimentally that with values of identification accuracy K of 90%, the number of duplicate measurements as compared with the known one is reduced by 30-40%.

Claims (1)

Invention Formula A method of identifying points in time with simultaneous recording of parameters of one or several processes, consisting in simultaneous recording of synchronizing signals at specified points in time, characterized in that, in order to increase the reliability of identifying moments in time of fast processes, once the registration of one or several processes is started with the help of external light radiation they put a mark on the carrier of the photo recorder, in the place of the mark they establish a receiving receiver, and synchronize iruyuschie signals form the photodetector to register the time of the image process. xs  / FIG 1