SU1437987A1 - Digital time discriminator - Google Patents

Abstract

The invention relates to: a pulse technique and can be used in telemetry systems with phase information and rangefinders. The aim of the invention is to improve the accuracy of determining the position of the input pulse relative to the strobe pulse. The discriminator contains the input Yenu 1, pin 2 of the gate pulse, reset bus 3 , svitnu ptnu 4, delay line 5, elements OR 6 and 11p register 7, trigger 8, elements 9 and 10 matches, de. Ledger 12. As a result of the proposed circuit design and corresponding functional connections s of the proposed digital time slot, the accuracy of determining the position of pulses is improved without increasing the number of circuit elements included in it. With the same accuracy as the prototype, the invention also makes it possible to significantly simplify the design of the device and increase the reliability of its operation.

Description

I

 a 1 B

3

4; iii

7 –C 12

D

The invention relates to a pulse technique and can be used in telemetry systems with phase information presentation and in radio range finders.

The aim of the invention is to improve the accuracy of determining the position of the input pulse relative to the strobe pulse.

The drawing shows a functional diagram of the described digital time discriminator.

Discriminator content input bus 1, bus 2 strobe pulse, bus 3 reset, code bus 4, line 5 delay, element OR b, register 7, trigger 8, elements 9, 10 matches, element OR 11, decoder 12, while input bus 1 and bus 3 are connected to the first and second inputs, respectively, of the trigger 8, the inverse output of which is connected to the first input of the coincidence element 10, the output of which is connected to the first input (OM of the OR element 11, the second input of which is connected to the output of the coincidence element 9, and output through line 5 - delays - with the first input of the element OR 6, the second input of which is connected to the gate 2 bus gate, and the output to the first input of the coincidence element 9 by the second input of the coincidence element 10 and the first input of the register 7, the second input of which is connected to the reset bus 3, the third input to the second input of the element 9 co-taps and the input bus 1, and the outputs - with the inputs of the decoder 12, the output of which is connected to the output bus,

Digital time discriminator works as follows.

Before each cycle of probing via the resetting bus 3, the trigger 8 is set to the zero state, and in the register 7 it is written 1 in the junior digit.

The temporal mismatch between a target pulse of duration and a strobe pulse of duration t Su / n (where n is the scale factor determining the discriminator's accuracy) determines three possible modes of operation of the discriminator,

1, Strobe-pulse arrives earlier than target impulse,

In this case, a gate pulse is applied by pin 2 to the second input of the element I; PI 6, from the output of which

Q

with

five

to the first input of register 7, which was simultaneously a write and shift pulse. Prior to the arrival of the target pulse through the input bus 1, due to the presence of a high level at the output of the trigger 8, the feedback of the delay code 5 on the circuit of the encoder-element OR 6 — the output of the coincidence element 10 — the output of the element OR 11, which allows looping the gate-pulse, closes. Each cycle of the strobe pulse in register 7 is written O, At the time of arrival of the target pulse, trigger 8 is set to the opposite state. The feedback circuit of the delay line 5 closes through the coincidence element 9, register 7 is recorded 1 for the entire duration of the target pulse, with the end of the target pulse, the feedback of the delay line 5 is broken, the gate-pulse stops circulating, writing information to the register 7 stops . In register 7, an error code will be generated between the target pulse and the strobe pulse. The mismatch code recorded in the register is converted by the decoder 12 into a code necessary for the consumer,

2. The gate pulse arrives simultaneously with the target pulse.

This case: is a special case of the first and differs from it only in that the register 7 will generate a code indicating that there is no mismatch between the target pulse and the strobe pulse.

3. The gate pulse arrives later than the Tsbsh pulse

In this case, prior to the arrival of the strobe pulse, there is no process of circulation of this pulse along the feedback circuit of the delay line 5. The information in register 7 is not recorded. At the time of arrival of the strobe pulse and during its circulation through the feedback circuit, the delay line 5 until the end of the target pulse is written to register 7. information in register 7 is terminated. In register 7, an error code is generated between the target pulse and the strobe pulse. The register size 7 is determined by the scale factor n and may be, for example, 2 n, where n 8,

31

The unit (1), recorded in the low-order bit of register 7, allows determining the mismatch code between the target pulse and the gate-pulse in the first variant of the discriminator operation before each probe cycle. 1 in the nine least significant bits of register 7 indicate that there is no mismatch between the target pulse and the strobe pulse.

If 1 is recorded in less than nine lower bits of register 7, then the mismatch code between the target pulse and the gate pulse for the 3rd variant of the discriminator is determined.

For the discriminator to work stably, the scale factor n must be greater than or equal to 8 (n 8).

The delay line in the prototype has n taps, which is equivalent to a serial connection (n - 1) of delay lines with a delay time of € j Cq / n each. Thus, with n 8, the prototype will consist of seven series-connected delay lines with a delay time of 7Cj, eight AND circuits, a register, and a decoder. The total number of elements will be 17. In the proposed digital time discriminator, there is only one delay line, which has no intermediate terminals, with a delay time Tj. The total number of elements included in the composition of the proposed device is 8, which is approximately two times less than in the prototype.

To increase the measurement accuracy of the time error (decrease quantization errors) by a factor of N, the scale factor η must also be increased by a factor of N. Here N is the multiplicity factor of the increase in accuracy. In this case, the number of circuits And in the prototype will increase by N times, and the number of delay lines with the time delay with / N will become (- 1). In turn, in the proposed device, in this case, the number of functional elements does not increase, only the delay time of the delay line is reduced N times. At the same time, in the prototype and in the proposed device, the duration of the strobe pulse 2a decreases N times, and the number of registers in registers increases N times. When N 2 the number of functions

0

five

0

five

In the proposed device, it remains equal to 8, and in the prototype it becomes equal to 33.

It is known that when a signal propagates through series-connected delay lines, the waveform is distorted, which leads to a decrease in the reliability of the device. To eliminate this drawback, signal conditioners are installed in the devices after one or two delay lines. Thus, in the prototype, the number of functional elements will increase by another number of signal conditioners, while in the proposed discriminator, the driver is not required.

Thus, introducing new elements and connections into a digital time discriminator allows one to increase the accuracy of determining the position of a pulse without increasing the number of incoming elements or (with the same accuracy) simplifying the design of the device and increasing its reliability.

Claims (1)

Invention Formula The 1.1-time temporal discriminator contains a register whose first input is connected to the reset bus, and the outputs to the decoder inputs whose output is connected to the output bus, the first match element, the first input of which is connected to the input bus, the second match element, the delay line and a strobe-pulse bus, characterized in that, in order to increase accuracy, a trigger and two OR elements are additionally introduced into it, the input bus and the reset signal are connected respectively to the first and second trigger inputs, the inverse output to the then connected to the first input of the second coincidence element, the output of which is connected to the first input of the first OR element, the second input of which is connected to the output of the first coincidence element, and the output through the delay line to the first input of the second OR element, the second input of which is connected to the strobe bus pulse, and the output - with the second inputs of both elements of coincidence and register, the third input of which is connected to the input bus.