SU790170A1 - Low-frequency sawtooth generator - Google Patents

Description

I

The invention relates to a pulsed tech and can be used in programming devices.

A device for generating {) the connection of a sawtooth voltage is known, which contains a generator controlled by an input signal and a frequency converter in analog voltage l.

N9D (x: tat device) - the difficulty of controlling the inclination of the sawtooth, for example, short and low noise immunity

Also known is a low-frequency sawtooth generator, containing an AND-cascade integrator, a null comparator whose output is connected via a resistor to the base of the transistor of the regulating cascade, the output of the integrator is connected via a differentiating element to the input of the zero comparator, and the collector of the transistor of the regulating cascade is connected through a resistor with a transistor base of the second stage of the integrator 2 stage.

The disadvantage of the generator is the limited duration of the direct sawtooth voltage code with high linearity and amplitude stability.

The circuit of the invention is an increase in the duration of the forward stroke of the saw-tooth voltage with high linearity and stability of amplitude.

The goal is achieved in that a low-frequency sawtooth generator containing series-connected differentiator, null paraparator, control cascade and integrator is entered an adder, comparator, series-connected pulse generator, electronic key, pulse counter, code-voltage converter, the output of which connected to the first input of the adder - the second input of which is connected to the integrator output, the output to the input di (|) of the ferentiator and to the first input of the comparator, the second input to It is connected to the reference voltage bus, and the output is connected to the control input of the key.

Claims (1)

The drawing shows a structural electrical circuit of the device. 3 -79 The device contains an integrator 1, an adder 2, a code-voltage converter 3, a pulse counter 4, a comparator 5, an electronic terminal 6, a generator of 7 pulses, a differentiator 8, a null comparator 9, a regulating stage 1O. The low-frequency sawtooth generator operates as follows. The sawtooth voltage from the output of the integrator 1 is fed to the input of the adder 2, is scaled in it and from its output goes to the inputs of the differentiator 8 and the comparator 5. When the voltage from the output of the adder 2 reaches, the reference voltage across the other input of the comparator 5, the comparator 5 works and closes the electronic capacitor 6, allowing the passage of pulses from the generator 7 samples to the input of the counter 4 pulses. In this case, the pulse counter 4 begins to fill and, at the output of the converter 3, the code-voltage appears a piecewise-step voltage of another sign with respect to the output voltage of the integrator 1. When the voltage from the output of the converter 3 code-to-voltage is reached The voltage of a higher voltage than the output of the integrator 1, the voltage at the output of the adder 2 abruptly changes its polarity. A change in polarity at the output of the adder 2 causes the slab (the comparator 5 opens the electronic key 6, prohibits the pulses from passing to the pulse counter 4. In the next cycle, the linearly varying voltage from the output of the integrator 1 С5г1 is generated in the adder 2 with a constant voltage c the output of the code-voltage converter 3. The voltage at the output of the differentiator 8 is propordered at the rate of change of the saw-tooth voltage of the integrator 1, When the voltage deviates at the output of the differentiator 8 from the reference voltage to the input comparator nup; 9, at its output, a mismatch signal is obtained which, through the regulating cascade Yu, changes the inclination of the sawtooth in the direction of the mismatch between the voltage at the output of the differential attor 8 and the reference voltage. The voltage applied to the input of the differentiator 8 from the adder 2 Is an alternating and symmetrical one, and hence the error introduced by the leakage of the capacitor of the differentiator will also be alternating and symmetrical. The mean square error of the sawtooth voltage reproduction from the leakage of the capacitor of the differentiator in the period between the two times of the comparator is close to zero. The duration of the forward stroke of the sawtooth voltage is determined by the scale of the adder 2, the capacity of the counter 4 pulses and to a lesser extent depends on the constant time of the differentiator 8. As a result of the error due to leakage of the capacitor of the differentiator 8, the determining linearity and stability of the sawtooth voltage , is practically zeroed out, changing the transfer coefficient of the adder 2 and the capacity of the counter 4 pulses, it is easy to increase in a wide range the duration of the rise of the saw voltage. With a 7-bit binary counter, the distance between the sawtooth voltage up to 10 ° C is easily achieved with an error of linearity and amplitude stability not worse than 0.5%. Claims A low-frequency sawtooth generator comprising a series-connected differentiator, a null-paraparator, a control cascade and an integrator, characterized in that, in order to increase the duration of the forward stroke of the saw-tooth voltage with high linearity and amplitude stability, an adder, comparator and sequentially are entered into it connected pulse generator, electronic key, pulse counter and code-voltage converter, the output of which is connected to the first input of the adder, second second input of which is connected to the output of the integrator, the output - to the input of the differentiator and the first input of the comparator, the second input of which is connected to a reference voltage bus, and an output - to the control input of the electronic key. Sources of information taken into account in the examination 1. US patent number 3783392, cl. Q 06 g 7/18, 1974. 2, USSR Copyright Certificate No. 406206, cl. Q 06 g7 / 18, 1974.