RU4423U1 - DEVICE FOR ISOLATING A TASK ACCORDING TO A PULSE ACCOUNT FROM A SEQUENCE - Google Patents

Abstract

A device for extracting a predetermined pulse count from a sequence comprising a frequency divider with a variable division coefficient and a gating circuit, the counting input of the frequency divider being an input to the device, characterized in that the strobing circuit is made on a D-trigger, the frequency divider is synchronous with setting the division factors, the transfer output of the frequency divider is the output of the device and is connected to the counting input of the D-trigger, the inverse output of which is connected to the input of the D-trigger, the direct output is to the input m zero-setting the frequency divider, the input of the zero D-flip-flop is connected to the bus reset.

Description

A device for extracting a given schulse from a sequence

The proposed utility model relates to a common technique and can be used in devices where it is not necessary to extract any given pulse from a pulse sequence.

A device is known for separating a given pulse count “1 pulse, containing a frequency divider with a variable division coefficient, a coincidence element, and a trigger IlJ. The disadvantage of this device is the occurrence of an error at high frequencies of repetition of n pulses, due to the fact that the signals at the inputs of the coincidence element have a different time delay. As a result, the leading edge of the extracted pulse is shifted by the delay time in the divider, and the pulse itself is shortened.

The closest in technical essence to the proposed utility model is a device for extracting an inverted pulse train from a sequence containing a strobe frequency divider with a variable division coefficient and a gating circuit made on three 55 triggers, the input of the frequency divider being the input of the device, the output of the frequency divider is the output of the device and is connected to the input of the first trigger, the output of which is connected to the input of the second trigger, the output of which is the second output of the device and connected with input S of the third trigger, input IL of which is connected to the first input / c of the frequency divider, from the first input / i of the first trigger and to the control bus; the inverse output of the third trigger is connected to the second input of the "first trigger and second input of the frequency divider 2y. The disadvantages of the device are the complexity and high performance. The latter is due to the fact that the signal gating the frequency divider must go through three triggers. In this case, the rear front of the output shushulza will be shifted by the delay time of the three triggers, and the pulse itself is elongated. In addition, during the operation of the device, malfunctions are possible due to the fact that the used SHUYU-triggers give a forbidden combination of input signals, namely, when a logical unit appears at both inputs of a logical unit, the output state of the trigger becomes determined1 1 3J,

The objective of the proposed utility model is to simplify the circuit and increase speed and reliability.

The essence of solving the problem lies in the fact that in the device for extracting a given pulse from a sequence containing a frequency divider with a variable division coefficient, the input of which is the input of the device, the gating circuit is made on a 1) trigger, the frequency divider is synchronous, the transfer output of the frequency divider is the output device and connected to the counting input of the trigger, the inverse output of which is connected to input 7), a direct output to the input of the zero setting of the frequency divider, the input of the zero setting of the trigger with union of a 1DINOY reset.

In FIG. I shows a diagram of the device, and in FIG. 2 - stress diagrams at various points.

The device consists of a synchronous frequency generator with a variable division coefficient I, J) - trigger 2, input bus 3, output pp-4 and reset bus 5.

Initially, the logical unit level is applied to the reset type 5 / The device operates as follows. Upon arrival at the counting input of the frequency divider I of the input pulse (Fig. 2, a), a pulse will appear on its transfer output, the serial number of which is equal to the specified division coefficient (in Fig. 2, c, Kdel-4), along the trailing edge of this pulse trigger 2 is transferred and a logical unit appears at its last output (Fig. 2, c), which prohibits the operation of divider I. Moreover, the device does not respond to input signals. Upon the arrival of the reset pulse to bus 5, trigger 2 returns to its initial position, allowing the frequency divider to work. Upon arrival at the input bus 3 shchulsov device operation is repeated.

The device was used to measure the speed of ultrasound in a medium by an echo-pulse method. Using a piezoelectric sensor, a sequence of echo shushuls was excited in the sample, which underwent a different number of reflections. The timing scheme forces short Zhschulsa, whose fronts are tied to the moment of transition of the oscillations of the echo pulses through zero. The speed of ultrasound is determined by the time interval between the selected pair of m-i pulses from this sequence. These pairs are highlighted using the two proposed devices. The condition for an unambiguous correspondence between the selected time interval and the delay between the IVI and the echo pulses is the mishal distortion of the temporal position of the fronts and the duration of the forced tsuls. The use of device l for this purpose does not meet this requirement. For example, the use of a counter having a delay of 25 does not lead to the appearance of a noticeable measurement error already at a frequency of 4.

UO ///// t-f The device sj cannot be used for this purpose, because does not allow to select the first schuls from the sequence. This is due to the fact that the output trigger is triggered only by the (K + 1) th clock.

The proposed device is structurally simpler. And fully meets the requirements, since the delay of the fronts of the highlighted pulses is the same and does not depend on the division coefficient. The pulse duration also does not change.

An experimental check of the pre-locked device showed that it is possible to select any given w, pulse from I to 16, using one double counter, and the device remains operational up to a frequency of 430 ICs.

In addition, the proposed device is much simpler than the known devices and MvieeT more reliable.

Sources of information taken into account when compiling the description

1. USSR Certificate of Authorship

Zh078602 1Zh14 NOZK5D53, publ. in V.I. 1984, J 9.

2. The author's certificate of the USSR J 938622 ivKIi NOZK5D53 publ. in V.I., 1982, 11.19.

3.Putikov B.C. Integrated electronics in measuring devices. - L .: Energy, 1980 .-- 248 p.

Claims (1)

A device for extracting a predetermined pulse count from a sequence comprising a frequency divider with a variable division coefficient and a gating circuit, the counting input of the frequency divider being an input to the device, characterized in that the strobing circuit is made on a D-trigger, the frequency divider is synchronous with setting the division factors, the transfer output of the frequency divider is the output of the device and is connected to the counting input of the D-trigger, the inverse output of which is connected to the input of the D-trigger, the direct output is to the input m zero-setting the frequency divider, the input of the zero D-flip-flop is connected to the bus reset.