SU1443142A1 - Sawtooth voltage shaper - Google Patents

Abstract

The invention relates to a pulse technique and can be used, for example, in sawtooth generators. The purpose of the invention is to increase the accuracy of the device by increasing the accuracy of setting a given initial level of output sawtooth signals. For auto-tuning of a given initial level of the output signal, serve a comparator 8, an integrating circuit 10, a key 9, which briefly closes under the deist

Description

ABOUT)

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the signal from the third output of the control unit 6. The signal from the second output of the block 6 short-circuits the key 5, and depending on the state of the comparator 2, the state of the integrator 4 changes, which is the source of the reference voltage of the integrator 1, which is reset by the signal from the first output of the block 6. The output voltage of the repeater 7 ensures that the output voltage is formed symmetrical about the zero level, regardless of the magnitude of the reference voltage on the bus 3. 1 sludge.

one

The invention relates to a pulse technique and can be used, for example, in sawtooth generators.

The purpose of the invention is to improve the accuracy of work by increasing the accuracy of the installation of a given initial level of output sawtooth signals.

The drawing shows a structural electrical driver circuit. The sawtooth voltage driver contains an integrator 1 with a reset, the output of which is connected to the first input of the comparator 2, the second input of which is connected to the bus 3 of the reference voltage source, an integrator 4, the output of which is connected to the input of the integrator 1 with a reset, controlled key 5 The control input of which is connected to the first output of the control unit 6, the second output of which is connected to the control input of the integrator 1 with a reset, the control key 5 is connected between the output of the comparator 2 and the input of the integrator 4.

In addition, the driver contains a voltage follower 7 on a single-stage amplifier, the first input of which is connected to bus 3 of the reference voltage source, the second input to the output of integrator 1 with reset, additional comparator 8, additional control switch 9, integrating the CS- circuit 10, the code of which is connected to the auxiliary input of the integrator 1 with a reset, the input to the output of an additional controllable switch 9, the input of which is connected to the output of the additional comparator §, the first input of the latter is connected to the output

integrator 1 with a reset, and the second input - with the common driver bus; the control input of the additional control key 9 is connected to the third output of the control unit 6,

At the second output of block 6, the impulses controlling integrator 1 are developed. At the first and third outputs, time-separated impulses coincide in time, respectively, with the leading and falling edges of the impulses generated at the second output of the control unit.

The shaper works as follows.

With the arrival of a logical O at the input of the driver, the integrator; 1 operates in an integrated mode and a linearly varying voltage is applied to the output of the shaper. The output voltage U, of the first output of the driver with the aid of comparator 2, is compared with the output voltage of the bus 3 of the voltage source. The output voltage of the comparator is positive if U, and negative if U, Uflq.

The amplitude of the output voltage of the driver is determined by the voltage of the second integrator 4 (playing the role of the analogue of the external device) and the frequency of the input pulses.

When the input signal changes from logical O to logical 1, the integrator output voltage drops and simultaneously, under the action of a signal coming from the second output of control unit 6, a short circuit of the key 5 occurs. At the same time, the input of the integrator 4 receives a short-term positive or negative (depending on the state of the comparator 2 at the moment when the integrator integration process 1 finishes) a pulse that changes the output voltage of the integrator 4.

Suppose, for example, that the amplitude of the output voltage is less than the positive reference voltage. Then at the time of the closure of the key 5 at the output of the comparator 2 is a positive voltage and a brief positive pulse arrives at the input of the integrator 4. As a result, the output negative voltage of the integrator 4 increases in absolute value and during the next period of sawtooth pulses the amplitude of the output signal will increase. The amplitude increases until it reaches the reference voltage level, after which the amplitude is kept constant and equal to the reference voltage with an accuracy of a certain iUft value (the amplitude of the pulses after each period alternately increases or decreases the magnitudes of Vgn, differing from it no more than. on a ld).

A similar process occurs in the event that, for any reason, the amplitude of the pulses becomes greater than the reference voltage.

The magnitude of LID, which determines the maximum deviation of the amplitude of the output pulses of the former from the level of the reference voltage, is given by the following expression:

and Hi-Li i A RIC R С

(one)

- the absolute value of the positive and negative output levels of comparator 2;

- pulse repetition period; - the duration of the closure of the key- 50

cha 5;

i, C4 are the parameters of the corresponding resistors and capacitors of the integrators 1 and 4. R, the expression (l) can be the expression 55

whether

  R.C4

(2)

From expression (2) it can be seen that, by decreasing the btg value or by increasing the product R4-4, the value MJ can be reduced to the required, predetermined value, thereby ensuring the necessary level of amplitude stability.

At the output of the integrator 1, a sawtooth voltage U is formed, varying from zero to + U | ,. The voltage .and the output of the repeater 7, connected to the second output of the driver, is determined by the switching circuit of the operational amplifier, and provided that the values of the resistances of the resistors are equal, is given by

, -and, „. (3)

From the expression (3) it is obvious that with; linear variation of the voltage U (from zero to + Uon, the voltage Us varies linearly from -11 to + U regardless of the value of U. This means that the output voltage on the second the output of the driver remains symmetric with respect to the zero level regardless of the value of C), i.e., regardless of the amplitude of the output signals.

A comparator 9, a key 9, and an integrating EC circuit IO are used for the auto subtraction of a given initial level of the output signal.

The comparator 8 compares the output voltage U, of the integrator 2 with the zero voltage of the common wire of the circuit. The output voltage of the comparator is positive if, and negative, if.

When the input signal changes from logical 1 to logical O, the output voltage of integrator 1 begins to increase and at the same time, under the action of a signal from the third output of control unit 6, a short-term switch 9 is applied. At the same time, a short-term positive is fed to the input of the integrating RC circuit 10 or a negative (depending on the state of the comparator 8) pulse. Under the influence of these pulses, the capacitor of the integrating RC-chain 10 is automatically. is charged to a voltage of such magnitude and polarity that provides a predetermined zero voltage level of the output signals of the integrator I with

514431

reset at the initial moments of the forward sweep stroke.

In the steady-state mode, the accuracy with which the zero level of the output sawtooth signals of the integrator 1 is maintained with the fault can be measured by means of

. ,, Uiceita uUo- -

R

(BUT)

where

(oh

ten

i

ten

the absolute value of the positive and negative output levels of the comparator 8; 15 & t is the closure duration of the key 9;

the parameters of the resistor and capacitor of the integrating HC-chain 10.20 By reducing the value of utg or by increasing the product ,,,, you can ensure the necessary accuracy of setting the initial value of the output signals. Thus, in the obes-25 scheme, automatic adjustment is made to the specified values as amplitude

0

five

0 5

42 6

so the initial level of the output sawtooth signals with the required degree of accuracy.

Claims (1)

Invention Formula Sawtooth shaper according to auth. St. No. 1262705, dated. characterized by the fact that, in order to improve the accuracy of work, due to the increased accuracy of the installation of a given initial level of output sawtooth signals 5, an additional comparator was introduced in it, an additional control key integrating an RC-depot, the output of which is connected to an additional input of the integrator with a reset, input - with the output of an additional controllable key, the input of which is connected to the output of the additional comparator, the first input of which is connected to the output of the integrator with a reset, and the second input - to the common bus form ers, the additional control input controlled yuschy .l emogo switch connected to the third You are a: swing control unit.