SU588630A1 - Time interval-to-didital code converter - Google Patents

Description

one

The invention relates to radio engineering, a pulse technique, and can be used in digital time interval gauges.

A known time interval transducer is a digital code comprising a counting pulse generator, a time selector, a pulse counter, and a digital reading device 1.

A disadvantage of the known device is the presence of a conversion error due to the displacement of flip flip-flop due to the steepness of the pulse front.

Another converter is known, which contains series-connected triggers, a control trigger, two valves and a delay line 2.

A disadvantage of the known converter is the low accuracy of the conversion, which is explained by the fact that the trigger of the first discharge reduces the sampling error by half at a constant frequency of the counting pulses only for the trailing edge of the converted time interval.

In order to increase the accuracy of conversion to a converter containing triggers of the first and second bits, two gates, a delay line connected between the gates, and a control trigger, the outputs of which are connected respectively to the control inputs of the first and second gates,

the first and second OR elements, the third valve, an additional delay line, a differentiation unit, a negative element and a pulse expander, the inputs of the first and third valves being combined, and the control input of the latter connected to the control input of the second valve, the output of which is connected to one of the inputs the first element OR, its second input through a series-connected negative element and a differentiation unit connected to the control input of the first valve, and the output to the counting input of the first discharge trigger, in the output of the third valve is connected to one of

the inputs of the second OR element and through the pulse expander - with the control input of the negative element, while the second input of the second OR element is connected via an additional delay line to the output of the first discharge trigger and its output to the counting input of the second discharge trigger.

The drawing shows the block diagram of the device.

The converter contains the trigger of the first bit 1, the trigger of the second bit 2, the first and second elements OR 3 and 4, the first, second and third valves 5, 6 and 7, the delay line 8, the additional delay line 9, the negative negative element 10, the expander

pulses 11, differentiation unit 12 and control trigger 13.

The Converter operates as follows.

In the initial state, the outputs of trigger 13 are low and high and potential. The system of elements is selected so that only valve 5 is open. Triggers 1 and 2 are in the zero state.

At the time of the start of the start-imiuls to the input of the trigger 13, the latter is tilted, the valves 6 and 7 are opened, and the valve 5 is closed. In this case, the pa of the input of the delay line 8, by counting on the half-cycle of the counting pulses, the counting pulses are not received, but through the open valve 6 and the OR element 3 to the input of the trigger 1 passes the delayed pulse from the output of the delay line 8, if the start-pulse is in the nerve half-period counting pulses. This delayed pulse overturns trigger 1 to the state "1. If the start-up pulse is in the second half-cycle of counted pulses, the valve 5 opens already after the arrival of the delayed pulse and therefore the trigger 1 remains in the initial state "O.

At the same time, the arrival of the start-pulse counts the counting pulses through the valve 7 and element 4 to the counting input of the second trigger 2. At the same time, the counting pulses from the output of the valve 7 enter the input of the pulse extender I, which forms emulsions with a duration equal to half a period counting pulses.

At the time of arrival of the stop pulse to the input of the trigger 13, the latter is set to the initial state, the valves 6 and 7 are closed, and the valve 5 is opened. The positive differential at the output of the flip-flop 13 is differentiated by the block 12. The pulse from the output of the block 12 passes through the element 10 and the element OR 3 to the counting input of the flip-flop 1, if the stop-pulse is in the second half-period of the counting pulses. This pulse overturns trigger 1. If trigger 1 was previously in state "1, then it returns to state" O and the pulse from its output through the delay line 9 and element 4 enters the second-trigger trigger input 2. Liya Delay 9 has a delay time greater than the transient time in trigger 2.

If the stop pulse is in the first half period of the counting pulses, then the pulse with

the output of block 12 will not pass through the negative element 10, since the prohibitive voltage from the output of the pulse extender 11 is applied to the control input and the last for the first half period of the counting pulses. Trigger 1 will not change its state.

Thus, the trigger of the junior bit 1 is not involved in the count, and its speed

can be significantly lower than the speed of trigger 2. However, trigger 1 halves the sampling error at a constant frequency of the counting pulses. At the same time the mean square error

discreteness for the beginning and end of the converted time interval is the same.

Claims (2)

1. Mirsky G. Ya. Radio-electronic measurements, “Energie, M., 1975, p. 176. 2. USSR author's certificate No. 427468, cl. H OZK 13/20, 1974.