SU789756A1 - Electric pulse mark-to-space ratio oscillographic meter - Google Patents

Description

The invention relates to electrical measuring equipment and can be used in devices for measuring signal parameters. The closest to that proposed by the technical entity is an oscillographic meter for the duty cycle of electric pulses, containing an amplifier, a unit for synchronizing and generating a linearly varying voltage sweep, an electro-ray tube, a horizontal deflection control unit, a voltage source, horizontal displacement, analog adder, D / A converter , two-clock analog-to-digital converter, indicator and reference voltage source. A disadvantage of this device is a large measurement time,. due to the need to measure the NIN duration of two time intervals and determine their ratio. The purpose of the invention is to reduce the measurement time. To this end, an oscillographic electric pulse duty cycle meter, containing an amplifier, whose input is connected to the device input and the input of the synchronization unit and the formation of a linearly varying voltage sweep, and the output - to the vertical deflection plates of the electron-beam tube, the horizontal deflection plates connected to the output of the block horizontal deviation control, the first input of which is connected with the output of the synchronization unit and the formation of a linearly varying voltage sweep, and The input is with a voltage source output. The horizontal movement and the first input of an analog adder, the second input of which is connected to the output of a digital-to-analog converter, and the output to the first input of an analog-digital push-pull converter, the first output of which is connected to the indicator input, and the second output to input digital-to-analog converter, and the source of the reference voltage, equipped with a source of adjustable voltage, key control unit and two keys, outputs. which are connected with the second The input of the analog-to-digital-to-digital converter of the push-pull integration, controllable inputs with the outputs of the key management unit, the input of the first key - with the onoprforo voltage source, the input of the second key - with the adjustable voltage source.

The drawing shows a structural, electrical circuit of the device.

The device consists of an amplifier

1, electron beam tube (CRT)

2, block 3 of synchronization and the formation of a linearly varying voltage sweep, block 4 controls the horizontal deviation, the source 5 voltage Moves horizontally, analog adder 6, D / A converter

(D / A) 7, the source 8 of the reference voltage, the first key 9, the analog-digital converter (ADC) 10 of the push-pull integration, the indicator 11, the block 12 controlling the keys of the adjustable-voltage source 13 and the second key 14.

The device works as follows.

In the initial state, the key 9 is closed, the key 14 is open.

The tested signal goes through the amplifier 1 to the vertically deflecting plates of the CRT 2 and to the input of the synchronization unit 3 and the formation of a linearly varying voltage sweep. .

After the image of the investigated pulse signal. synchronized, made, setting zero device. For this, the front from the first pulse of the signal under investigation is combined by changing the voltage of source 5. It is moved horizontally with the closest node of the grid of the CRT screen. Then, the output voltage of the DAC 7 is forcibly set to zero. In this case, the voltage at the output of the analog adder 6 and the second input of the A / D converter 10 is equal to Ujt-i. A / D converter converts / voltage U., to code. After removal of the forced setting at the output of the D / A converter 7, a voltage equal to the voltage Ujc is formed, and at the output of the analog adder 7 the voltage becomes equal to zero. The result of converting the ADC 10, operating in cyclic mode, directed to the indicator 11, is also zero. At this point, the zero setting ends and the measurement of the compensation voltage corresponding to the period of the signal under study begins. For this, the point on the image of the front of the second pulse of the signal under study, shifted by the following period relative to the point on the image of the front of the first impulse, is aligned with the same grid point with which the point on the image of the front of the first pulse was combined. This position of the image corresponds to the voltage of the O-source. 5 Horizontal movement. The voltage at the output of the analog adder 7 is equal to .Uy..Uy. . The result of the conversion of the ADC 10 is equal to;

. -.

 and"

eleven

where; DO is the reference voltage of source 8; K - conversion factor

ADC 10.

After this, the key 9 is opened, the key 14 is closed, as a result of which the second input of the A / D converter 10 is connected to the output of the source 13 of the regulated voltage. The result of the VDP 10 transformation becomes:

m:. .., ,,

 Up ,, 1

where: and

- source voltage 13.

per

The indicated result of the measurement of the next period is equal;

Z a-Zu1

T, -V ,.

and

per

Where; KQ is the steepness of the sweep, entered as a multiplier in the indicator I. Then the change in the discharge of the source 13 is made to obtain the readings;

  Ai n i, bt.

yug - Uy,

one

--ten

and

per

This is the case when the source voltage 13 is equal to:

,

rvg - (about "

After that, with the unchanged states of the keys 9, 14 and the voltage of the source 13, the drop of the first pulse of the signal under investigation is combined with the same grid point with which the front of the second pulse was previously combined.

Alignment is accomplished by varying the voltage of the source. 5 Horizontal movement.

The result of the conversion. ADC 10 is equal to:

--HlblJ

X1

V.

u

eleven

per

and the displayed result is equal to:

t -V s v.y "J,

 .s-iij; r - w °

With an appropriate choice of the value of n, the induced result is equal to the duty ratio H in percent.

The invention makes it possible to shorten the measurement time, simplify the measurement process and eliminate measurement errors of the duration of two time intervals and the division operation. Isoi

Claims (1)

Claim An oscillographic electric pulse duty cycle meter containing an amplifier, the input of which is connected to the input of the device and the input of the synchronization unit and generates a linearly varying scan voltage, and the output - with vertically deflecting plates of the cathode ray tube, horizontally deflecting plates connected to the output of the horizontal deviation control unit, the first input of which connected to the output of the synchronization unit and the formation of a linearly varying scan voltage, and the second input - with in sources swing-_ ka voltage Moving horizontally and the first input of the analog adder, a second input coupled to an output of the digital to analog converter, and an output - to the first input of the analog-digital converter integration push-pull, the first output is connected. to the indicator input, and the second output to the input of the digital-analog converter, and a reference voltage source, characterized in that, in order to reduce the measurement time, it is equipped with an adjustable voltage source, key control unit ^J and two keys, 15 outputs of which are connected to the second the input of an analog-to-digital push-pull integration converter, the control inputs are with the outputs of the key control unit, the input of the first 2Q key is with a reference voltage source, the input of the second key is with a variable voltage source .