SU367515A1 - DEVICE FOR REGISTRATION OF FORL \ S OF PERIODIC SIGNALS WITH A WIDE SPECTRUM - Google Patents

Description

one

The invention relates to a radio measuring technique and can be used to change the time scale of electrical processes and, in particular, to record the form of periodic signals with a wide spectrum.

A device for detecting a form of periodic signals with a wide spectrum is known, comprising a delay line, the output of which through an adder is connected to a threshold element with two inputs, a monotonic signal generator, an additional threshold element, a measuring device and a sweep voltage unit.

The disadvantages of the known device are the dependence of the accuracy of the time transformation on the shape of the monotonic signal and on the shape of the output pulse of the threshold elements and the difficulty of monotonizing fast processes with long repetition periods.

In order to improve the accuracy of registration of the form of periodic signals with a wide spectrum in the proposed device, the output of the time signal block, the input of which is fed an adjustable signal, is connected to the sweep voltage block, and the output of the threshold elements is connected to the integrator through the time discriminator with

which is simultaneously fed to the input At the measuring device and to the second input of the threshold element.

FIG. 1 is a block diagram of a device for detecting a periodic waveform with a wide spectrum; in fig. 2 shows the waveforms at various points in the circuit. The device works as follows. The input signal (see fwg. 2, a) through the line

/ delays, which are necessary to facilitate the registration of the initial part of the signal, are fed to the adder 2. At the same time, the input signal is fed to the block 3 of the time shift and starts it. Block 3 time shift triggers the generator 4 monotonic signal. Due to the effect of the time shift unit 3, the monotonizing signal (see Fig. 2.6) shifts in phase with respect to the input signal. The monotonic signal is fed to the additional threshold element 5 and the adder 2. Since the threshold voltage at the additional threshold element 5 is chosen constant, then a series of pulses of constant width is output at its output

(see Fig. 2, c), depending only on the selected threshold value. Since the shape of the monotonic signal is unchanged, the response phase of the additional threshold element 5 remains constant all the time.

After summation in adder 2, the resulting signal (see Fig. 2, d) enters the threshold element 6. If its threshold, like the threshold of additional threshold element 5, were constant, then as a result of the change in the shape of the input total signal due to the phase the shift between the input and monotonizing signals, the triggering of the threshold element 6 would occur in different phases relative to the monotonic signal, and the width of the output pulse of this element as the shift between the said signals would change. However, due to the presence of feedback from the integrator 7 to the threshold element 6 this does not occur. In fact, if the operation phases of the additional threshold element 5 and threshold element 6 do not coincide, the output signal of the time discriminator 8 is different from zero, which causes a change in the appropriate direction of the output voltage of the integrator 7. But this voltage is also the threshold voltage for the threshold element 6, and changing it causes a change in the triggering phase of the threshold element 6. The change in the threshold voltage continues until the triggering phase of the additional threshold lementa threshold element 5 and 6 do not become equal.

Thus, the output signal of the additional threshold element 5 plays the role of a reference signal, allowing the phase of the threshold element 6 to be maintained constant with respect to the monotonic signal.

Due to the presence of a varying phase shift between the input and monotonizing signals, the form of the sum signal entering the threshold element 6 changes all the time, trying to change the triggering phase of this element relative to the monotonic signal, and the integrator 7 prevents the change in the corresponding voltage direction the threshold of the threshold element 6 (see Fig. 2, d, dash-dotted line).

As the time shift between the input and monotonizing signals changes, the threshold voltage of the threshold element 6 will change, in the form of repetition of the input signal, stretched over time (constant

the component of this voltage, depending on the chosen triggering phase of the threshold elements, can be easily compensated at the output).

The voltage sweep unit 9, controlled by the time shift unit 3, outputs a sweep voltage proportional to the time shift between the input and monotonic signals.

The shape and duration of the working part of the monotonizing signal do not affect the accuracy of the time transformation. Since the triggering phase of the threshold elements relative to the monotonic signal remains constant, the working part of this signal can be very narrow, covering only the immediate vicinity of the point of operation, and the shape of this part does not matter. Enough if slope

the monotonic signal at the trigger point will be such that the time derivative of the sum signal at this point will not change sign during the entire conversion process.

The shape of the output pulses of the threshold elements does not play a role either, since for the temporary discriminator 8, the relative moment of the triggering of one threshold element relative to another is important.

subject matter

A device for recording a form of periodic signals with a wide spectrum, containing a delay line, the output of which through an adder is connected to a threshold element with two inputs, a monotonic signal generator, an additional threshold element, a measuring device and a unit

sweep voltage, characterized in that, in order to increase the registration accuracy, the output of the time signal block is connected to the inputs of the monotonic signal generator and the sweep voltage block,

to the input of which an adjustable signal is fed, and the outputs of the above-mentioned threshold elements are connected via a time discriminator to the integrator, the signal from which is simultaneously fed to the input U of the measuring device

and to the second input of the threshold element.

v.aZ

Fig 1