SU1465959A1 - Readjustable sawtooth voltage generator - Google Patents

Abstract

The invention relates to a pulse technique and can be used in sweep generators and pulse-pulse modulators. The purpose of the invention is to expand the functionality of the generator by ensuring the independence of the frequency tuning and amplitude of the sawtooth voltage. A counting trigger 6 and a current source 8 are introduced into the generator containing the operational amplifier 1, the control switches 2-5, the capacitor 7 and the control bus 9. By switching the keys 2-5, the capacitor 7 is connected to the source 8 of the current, then one or the other faceplate. The amplitude of the sawtooth voltage is controlled by the voltage on the bus 10, and the frequency on the bus 9. 2 Il. with $

Description

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The invention relates to the technology of pulses and can be used in automation and measuring devices 5 as well as in pulse-width modulators.

The purpose of the invention is. generation of generator-1 functionality due to providing IMOCTH frequency tuning and amplitude of generated sawtooth pulses,

Figure 1 shows the structural diagram of the proposed generator; FIG. 2 shows timing diagrams for the generator operation,

Generator (Contains (operational amplifier (OS) 1, the inverse input of which is connected to the first signal outputs of the first 2 and second 3 controlled keys, the second signal outputs of which are connected to the first signal outputs of the third 4 and fourth 5 controlled keys I, respectively The second signal OUTPUTS of which are combined. The forward code of the counting trigger 6 is connected to the control inputs of the second 3 and third 4 control keys, and the inverse output to the control inputs of the first 2 and fourth 5 control keys, counting trigger 6 is connected to the output of onepai i-gon amplifier 1, the direct input of which is connected to the common bus, and the inverse input is also connected to the output of current source 8, the control I input of which is connected to the bus 9 yn: the input is connected to A common bus, Between the second signaling pins of the first 2 n and the second 3 controlled keys, a time setting capacitor 7 is connected. The second exit of the third key 4 is connected to the amplitude adjustment pin 10 and the source code 8 is connected to the output bus 1t.

As a source 8, for example, a transistor cascade made according to a circuit with a common emitter with a resistor in the emitter circuit (control input — base output collector, input input — second resistor) can be used.

The generator works in the following manner.

Suppose that at the initial moment of time t 0 the counting trigger 6 is in the zero state, the control input of source 8 is supplied with a positive voltage, Ucr, and the second signal outputs of keys 4 and 5 are supplied with a positive voltage Up, then at the forward output of the trigger 6 there is a logical O signal, at AND: grain - logical 1 (FIG. 2a, b), at the outputs of the op-amp 1 — logical 2 and 5 keys are open, keys 3 and 4 are closed, and from source 8 output through the key 2 , capacitor 7 and key

5 bus 10 current flows equal to

I To Uynp, (1)

where K is the conversion factor

source 8.

Due to the flow of current I through the aforementioned circuit, the capacitor 7 is displaced, and since the voltage Up on the bus 10 is stable, the voltage at the output of the source 8 decreases linearly (Fig. 2c). As soon as this voltage becomes less than zero, at the output of the OA 1 a logical 1 signal will be set (Fig. 2d), on the leading edge of which the counting trigger

6 perebroshits in the opposite state. As a result, the keys 2 and 5 are locked, the keys 3 and 4 are opened. At that, the output of the capacitor 7, which was connected through the key 5

to the input of the regulating voltage will be connected via the switch 3 to the output of the source 8 and vice versa: the output of the capacitor 7, which through the switch 2 was connected to the source 8, will be connected through the switch 4 to the input of the regulating voltage, as a result of which the voltage on the inverse the input of the op-amp 1 jumps by an amount., l2Up, and at its output the signal logical o is set again. After this, the process is repeated from the beginning. The proposed generator generates a sawtooth voltage with a frequency equal to

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. (2)

and an amplitude equal to Di 2 Up,

(3)

providing a linear adjustment of the oscillation frequency along the bus 9 and a linear adjustment of the amplitude of the oscillations along the bus 10. In the latter case, with a constant voltage on the bus

9 does not ensure the constant steepness of the sawtooth voltage, which follows from (1). from (2) it follows that if you apply for tires 9 and 10 the same thing. voltage, it is then possible to adjust the amplitude of oscillations without changing the oscillation frequency.

Thus, in comparison with the prototype device, the proposed generator provides electronic frequency tuning of the generated oscillations without changing the sweep voltage of the sawtooth voltage, while maintaining the possibility of electronically adjusting the swing vibration and constant steepness of the sawtooth voltage during all cycles the constancy of the slope, it is necessary to satisfy the condition of equality of the capacitance of the two capacitors, which complicates the adjustment and increases the cost of manufacture in serial production. e.

one

Formula

acquisitions

A tunable sawtooth generator containing an operational amplifier, the inverse input of which is connected to the first signal pins of the first and second controlled keys, the second signal pins of which are connected to the first signal pins of the third and

1465959

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the fourth control keys, respectively, the second signal outputs of which are combined, the control input of the second control key being combined with the control input of the third control key, the control input of the first control key - with the control input of the fourth control key, a capacitor, one the output of which is connected to the second signal input of the second control key, the control bus, and the direct input of the operational amplifier is connected to the common bus, characterized in that, in order to expand the functions possibilities, a counting trigger and a current source are introduced into it, the direct output of the counting trigger is connected to the control input of the second control key, and the inverse is connected to the control input of the first control key, the counting input of the trigger is connected to the output of the operational amplifier, the inverse input of which is connected to the output of the current source, the control input of which is connected to the generator control bus and the input to the common bus, the second signal output of the third control key is connected to the amplitude adjustment bar, the second the capacitor lead is connected to the second signal lead of the first control key.

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Claims (1)

Claim A tunable sawtooth voltage generator containing an operational amplifier, the inverse input of which is connected to the first signal outputs of the first and second controlled keys, the second signal outputs of which are connected to. first signal terminals of the third and fourth control keys, respectively, the second signal terminals are combined with the _5-governing controlled input of the second controllable switch is integrated with the control input of the third controllable switch, the control input of the first controllable switch - to the control hodom chet- 10 of the fifth controlled key, a capacitor, one output of which is connected to the second signal output of the second controlled key, a control bus, while the direct input of the operational amplifier is connected to a common bus, characterized in that, in order to expand the functionality, a counted trigger and a current source of 20 ka, with the direct output of the counting trigger connected to the control input of the second managed key, and the inverse to the control input of the first managed key, the counting 25 input of the trigger to the output of the operation of an amplifier whose inverse input is connected to the output of a current source, the control input of which is connected to the generator control bus, 30 and the input to the common bus, the second signal output of the third controlled key is connected to the amplitude control bus, the second capacitor output is connected to the second signal output of the first managed key. '1465959 I ~ L_r ~ b-_Cl — FIG. 2