SU1396088A1 - Device for measuring fluctuations of the front of video signal - Google Patents

Abstract

The invention relates to a pulse technique, in particular, to devices for measuring temporal fluctuations of a pulse, and can be used in radio engineering devices for dynamic testing of vacuum tube microwave devices. The invention makes it possible to increase the speed of the performed measurements. The device contains a video amplifier 1, a generator 2 reference pulses, a software counter 3, an information display unit 4, an oscilloscope 5, delay lines 6 and 9, an operation mode switch 7, a fluctuation characteristic calculation unit 8, a coincidence element 10, an amplitude discriminator 11 and a pulse counter 12 . The information recorded in the pulse counter 12 is supplied to the information display unit 4 directly and through the fluctuation characteristics calculation unit 8. This block calculates such characteristics as rms, arithmetic mean and peak values. The calculation is made according to known mathematical formulas. 3 il. (From W to:

Description

with co (

oo

00

No. ./

The invention relates to a pulse technique, more precisely to devices for measuring temporal fluctuations of a pulse, and can be used in radio engineering devices intended for dynamic tests of EEP.

The purpose of the invention is to increase the measurement speed,

FIG. 1 depicts a structural. device layout; in fig. 2 .and 3 are oscillograms of stresses at characteristic points of the circuit.

The device consists of video amplifiers j bodies 1, oscillator 2 reference pulses, program counter 3, information display unit 4, oscilloscope 5, first delay line 6, mode switch 7, fluctuation characteristics calculation unit 8, 20, second delay line 9 , coincidence element 10, amplitude discriminator 11, pulse counter 12, when the output of video amplifier 1 is connected 25 to the first input of the oscilloscope 5 and the input of the second delay line 9, the first output of the generator 2 of the reference pulses is connected to the second input of the oscilloscope 5 and n rvym input of the first delay line 6 Q, and its second output - to an input of the program counter 3 output; software counter 3 is connected to the input of the switch 7 operating modes, the first output of which is connected to the input of the pulse counter 12, and the second output is connected to the BTopbtt-i input of the first delay line 6, the output group of the first delay line 6 is connected to the input group of the coincidence element 10, the input of which is connected to the output of the second delay line 9, the group of outputs of the coincidence element 10 is connected to the group of inputs of the amplitude discriminator 11, the group of outputs of which is connected to the group of inputs of the pulse counter 12, the output group of the counter 12 pulses connected to the first group of inputs of the information display unit 4 and with the group of inputs of the fluctuation characteristics calculating unit 8, the output group of which is connected to the second group of inputs of the information display unit 4, to the course of the video amplifier is the input of the device pulse being studied is the input trigger of the device. Video amplifier 1, first 6 and second 9 delay lines

35

40

45

50

d

0 5 Q

five

0

five

0

broadband, and the gain of the video amplifier can be adjusted. The reference pulse generator 2 produces an output pulse with negligibly small temporal fluctuations and an adjustable duration. The first delay line 6 is discrete, consisting of n series-connected precision delay elements with taps, and ensures complete overlap of the entire fluctuation range (Fig. 2). The second delay line 9 is made for a constant delay time exceeding the minimum duration of the generator 2 reference pulses. The coincidence element 10 and the pulse counter 12 are made in the form of n identical sneMCHTqa matches and pulse counters S and the amplitude discriminator 11 is in the form of n equal amplitude discriminators with an adjustable threshold and high resolution.

The device works as follows.

The pulse under investigation is amplified by video amplifier 1 and fed through the second delay line 9 to the common input of the coincidence element 10. A starting voltage pulse triggers a generator of 2 reference pulses, which produces an output pulse, which is fed to the first input of the first delay line 6. In the setup mode using the switch 7 operating modes, all elements of the first delay line 6 are shorted and provide a direct arrival of the output pulse of the generator 2 reference pulses simultaneously to all the inputs of the coincidence element 10, and

The control output of software counter 3 is disconnected from the input of pulse counter 12, which ensures continuous operation of the latter. Using an oscilloscope 5, the inputs of which are simultaneously examined and the reference pulses, achieve S by adjusting the transmission gain of video amplifier 1 to equal the amplitudes of the pulses fed to the inputs of the first 6 and second 9 delay lines, which are necessary for their normal operation and the coincidence element 10. The duration of the output pulse of the generator 2 is adjusted, increasing it until the decay of the reference pulse is not

: will be combined in time with the front

3139608

of the pulse under investigation (Fig. 2), with all the outputs of the element 10 of coincidence forming triangular pulses, the amplitude of which is proportional to the magnitude of the temporal fluctuations of the front of the pulse under study. These pulses arrive at the inputs of an n-channel amplitude discriminator.

11, the threshold of each of the IQ fluctuations is calculated; it calculates after 20 5s

which is set to approximately 50% of the pulse amplitude of the generator 2, and hence the amplitude of the amplified pulse under study. Every time when the amplitude of a triangular pulse formula: sa exceeds this level, counting pulses are formed at the outputs of the amplitude discriminator, which arrive at the counting inputs of the n-channel counter 12 pulses and are fixed by it. In the setup mode, the duration of the output pulse of the generator 2 is set so that all of the pulse counters included in counter 12 are at the threshold of batting time-25.

In the pulse-front fluctuation measurement mode, the mode-selector switch 7 is set to a position in which the output pulses of the generator 2 of the ra- tor 2 arrive at the inputs of the element 10, coinciding with a certain delay, and the first input receives a pulse with a delay of 4f, - on the third

following characteristics: arithmetic mean and root mean square, span (peak value). The calculation is made by the known

- .. ,, m

X.

m, + mj + ... + m ,,

... jLii 5il5im

+ m j +. . . + t „

where X h,

X, X ... X „

X.

- average arithmetic value,

- average square value,

-particle length intervals, and

 .,.

etc. (Fig. 3). At the same time / 5 p - 5 of

in this case, a complete overlap of the entire range of fluctuations is ensured. In the specified mode, on the first output of element 10, the amplitude of the triangular pulses will exceed AND, when the pulse duration and to "c1" with the second

35

m

sh,

exit when

, 2, etc.

,., ... t „are the sums of the frequencies of the interval variant, with ha N, m Nj 40 N,, ... ha n N n - N ,, ,, where N, Nj, ...

N is the number of pulses in 1,2.,. lah counter; / JX ,, ЛХ ... 4Хп deviations from the arithmetic mean value, moreover, l X, X, - X, 45-4 X, j - X,. . .ЛХ р X f, - X.

The counting pulses, generated by the amplitude discriminator 11, are recorded by counting counters included in the counter 12 pulses. The number of examined pulses undergoing processing is determined by program counter 3, triggered by the voltage pulse of generator 2. The pulse count stops at the signal generated by counter 3 at the moment when the number of the examined pulses received by the device becomes equal to the number previously set in counter 3. Information , - fixed in the counter 12 pulses, arrives

on the information display unit 4 directly and through the fluctuation characteristics calculation unit 8, in which characteristics such as the mean square value of fluctuations, the range of fluctuations, etc. are calculated.

Block 8 performance calculations

the fluctuations are calculated by the formula:

following characteristics: arithmetic mean and root mean square, span (peak value). The calculation is made by the known

formulas:

- .. ,, m

X.

m, + mj + ... + m ,,

5c

formulas:

... jLii 5il5im

+ m j +. . . + t „

arithmetic

quadratic sign

e intervals of length

-.d

35

m

sh,

,., ... t „are the sums of frequencies, the variant of the interval, with ha N, m Nj - N,, ... ha n N n - N. ,, where N, Nj, ....

N is the number of pulses in 1,2., .P. Channels of the counter; / JX ,, ЛХ ... 4Хп deviations from the arithmetic mean value, moreover, l X, X, - X, 4Х X, j - X,. . .ЛХ р X f, - X.

Claims (1)

Invention Formula A device for measuring fluctuations of the video pulse front, containing a video amplifier, a reference pulse generator, first and second delay lines, a coincidence element, an amplitude discriminator, a pulse counter, a software counter, an oscilloscope, an information display unit, and the studied pulses are fed to the video amplifier input, output which is connected to the first input of the oscilloscope and 5139 the input of the second delay line, trigger impulses: are fed to the input of the reference pulse generator, the first output of which is connected to the second input of the oscilloscope and the first input of the first delay line, and the second output is connected to the input of the program counter, the output of the second delay line is connected to the input of the coincidence element, characterized in that, in order to increase the measurement speed,: The block for calculating the characteristics of fluctuations and switching of the operating modes is introduced into it, the first delay line I is filled with discrete and corresponding to of the connected delay elements, the coincidence element, the amplitude discriminator and the pulse counter are made n-ka-: Nali and consisting respectively of n identical elements of the same, nor the amplitude discriminators and FIG. 2 0 0 five pulse counters, the group of outputs of the first delay line is connected to the group of inputs of the coincidence element, the first output of the mode selector switch is connected to the input of the pulse counter, the second input of the first delay line is connected to the second output of the mode selector switch, the output of the program counter, a group of outputs of the coincidence element is connected to a group of inputs of an amplitude discriminator, a group of outputs of which is connected to a group of inputs of a pulse counter, a group of output a pulse counter connected to the first group of display unit information inputs and a group of inputs characteristics calculating unit fluctuation band whose output is connected to the second group of the display information input unit. FIG. 3