SU993454A1 - Pulse duration forming device - Google Patents

Description

The invention relates to a pulse technique and can be used in control and information processing systems for generating pulses of controlled duration.

In practice, when developing similar systems with improved technical characteristics, it is necessary to have pulse shapers that would ensure the duration of output pulses strictly proportional to the values of the input numbers

A shaper is known that contains three triggers, a counter, a decoder, and a match element 1.

Such a device generates pulses of only the same duration and does not provide the possibility of changing the duration of the output pulses depending on the ratio of the input signals.

The closest to that proposed by the technical entity is the I-Shulsov shaper, comprising a pulse generator, a counter, an OR element, two triggers, two coincidence elements, a NOT pi element.

However, such a device is characterized by insufficient accuracy.

shaping the duration of the output pulses. This is due to the fact that the duration of the output pulses is not 5 strictly proportional to the input numbers.

The duration of the output pulses strictly correspond to the expression

"BblX fT-i n, I

ten

where n is the input number entered in the counter;

Tp is the duration of the pause between generator pulses;

T period of the pulse

15 generator.

that T G „+ S„,

Considering

Where

generator pulse duration, expression (1) takes the form

20

  t -j + tn. (2)

When entering into the counter various values of input chiels, for example, p. And Hg, of which one is larger than the other by K, the output of the device is output by 25 pulses, the durations of which are respectively equal to the expressions

Whose, x- "

). and;

thirty

From expressions (3) and (4) it follows that the ratio of the durations of the output pulses is not. Proportionally to the values of the input numbers, as can be seen from the expression (5)

IV-fjT.C p

OUT

 -i, (5)

one

(V / T

+ f.,

BblXj V2

This disproportionality of the duration of the output pulses to the input numbers is due to the fact that the driver for each (n-1) unit of the input number n provides a duration equal to T, and for one, the unit of the input number n is only equal to T, i.e. shortens its duration by the amount of a pause (Tp)

Disproportionality is indicated. is the error of the formed duration of the output pulses and the reason for the insufficient accuracy of the formation of the duration of the pulses.

The purpose of the invention is to improve the shaping accuracy by ensuring strict proportionality of the duration of the output impulses to the four-way numbers.

The goal is achieved by the fact that the pulse width driver, which contains a pulse generator, which is connected to the first input of the first matching element, and through the NOT element to the first input of the second matching element, the second input of which is connected to zero. the inputs of the first and second triggers on the output of the OR element, whose inputs are connected to the output terminals of the pulse counter, the output of the second coincidence element is connected to the single input of the first trigger, the output of which is connected to the second input of the first matching element, the output of which is connected to the single input of the second trigger , additionally introduced two elements of a match and a trigger, the single input of which is connected to the output of the first Additional element of the match; the first input of which is connected to the output of the element NOT, the second input is connected to the output of the second trigger, the zero input of the additional trigger is connected to the output of the OR element, the output of the additional trigger is connected to the first input of the second additional matching element, the second input of which is connected to the output of the pulse generator, and the output is connected to the counting input of the pulse counter.

The drawing shows a functional diagram of the pulse width driver.

The pulse width former contains a generator of 1 pulses; a counter of 2 pulses; an element

OR 3, triggers 4-6, elements 7 10, match, element NOT 11, input buses 12, output bus 13.

The pulse generator 1 is designed to form a clock pulse whose frequency is constant.

Binary counter 2 is intended for counting pulses in subtraction mode. The code at the output of counter 2 varies along the leading edge of the counting pulse.

Bus 12 receives the direct parallel binary code of the input number. Bus 13 output pulse.

The device works as follows.

Such an elemental base is selected at which the triggers 4-6 are set to the desired state by a low voltage level. In the initial state in the counter 2 there is a number whose value is zero, therefore at its outputs, and therefore at the output of the element OR 3, a low voltage level is set, which sets the triggers 4 - 6 to the initial zero state. -9 matches are set to high voltages, and at the outputs of the 4 to 6 triggers, low.

When a binary code of some input number n (n 1,2,3 ...) is entered into the counter 2, which corresponds to the specified output pulse duration, a high voltage level appears at the output of the OR 3 element. The triggers 4-6 do not react to this level, and in the pause between clock pulses conditions are created to trigger a matching element 7, since the output of the HE element 11 will also have a high voltage level. By a pulse from the output of the coincidence element 7, the trigger 4 is switched to one state, a high voltage level is set at its output. Further, on the leading edge of the pulse from the output of the generator 1, the coincidence element 8 is opened and the pulse from its output switches to one state the trigger 5, at the output of which a leading edge of the output pulse is formed.

Claims (2)

The output pulse from the output of the trigger 5 also enters the second input of the element 9 coincidence and prepares its opening on the falling edge of the pulse coming from the output of the generator 1 through the element NOT 11. In this case, the single input of the trigger 6 receives a signal with a low voltage level switches it to one state. The high voltage level from the output of the trigger 6 arrives at the first input of the coincidence element 10 and allows the clock pulses to pass to the counting input of counter 2. On the leading edge of each pulse, the counter of counter 2 is reduced by one. When the last unit of the input number is subtracted from counter 2, the output of the element OR 3 causes a low voltage level, which is reset to the initial zero state of the flip-flops 4-6 and blocks the coincidence element 7. At the output of the trigger 5, a falling edge of the output pulse is formed. Thus, the proposed shaper, in comparison with the known one, provides an increase in the accuracy of the formation of the duration of the initial pulses. This is possible because the duration of the output pulses of the string is consistent with the expression. PT where n is the input number entered into the counter g T is the period of the pulse of the generator 1. For any values of the input number of the input to the device, there will appear at the output of the generator pulses whose durations are strictly proportional to the values of the input numbers. Indeed i; . -.- g-. In the proposed former, the leading and trailing edges of the output pulse are generated along the leading edge of the generator 1, which is achieved by inhibiting the first pulse in the pulse train supplied to the counter input of the counter 2 by means of the trigger 6, coincidence elements 9 and 10. Claims: Pulse width generator comprising a pulse generator, the output of which is connected to the first input of the first match element directly and through the HB element to the first input of the second match element, the second input of which is connected to the zero inputs of the first and second triggers and b output of the element or the inputs of which are connected (with the bit outputs of the pulse counter, the output of the second element of the match is connected to the single input of the first trigger, the output of which is connected to the second input of the first The coincidence element, the output of which is connected to the unit ellum input of the second trigger, is characterized in that, in order to improve the shaping accuracy, two elements are additionally introduced in it, a coincidence element and a trigger, the single input of which is connected to the output of the first additional coincidence element, the first input of which connected to the output of the element is NOT, and the second input is connected to the output of the second trigger, the zero input of the additional trigger is connected to the output of the element OR, the output of the additional trigger is connected to the first input of the watt There is an additional element of coincidence, the second input of which is connected to the output of the pulse generator, and the output is connected to the counting input of the pulse counter. Sources of information taken into account in the examination 1. USSR author's certificate number 603109, cl. H 03 K 5/04, 1973, 2. Authors certificate of the USSR 790199, cl. H 03 K 5/04, 1979. I 12