SU657609A1 - Time interval-to-digital code converter - Google Patents

Description

The invention relates to the field of transforming and encoding information and can be used in devices for measuring time intervals. A digital automat is known for measuring the duration of a time interval, comprising a clock, a coincidence circuit, a counter, a trigger, and gates l. The disadvantage of it is the low accuracy of measurement of time intervals. A device is known that contains a counter, a first trigger, the first and second elements of a match, a delay line, two adders, a comparator and renepaTf p pulses, the output of which is connected to the first input of the first coincidence element, the second input and output of which are connected respectively to the output of the first trigger and the input of the counter connected with the output from the output of the device, and the first input of the second coincidence element is connected to the output of the comparator, the two inputs of which are connected through the first and second adders, respectively ervoy and second groups of taps of delay line 2. In this device a counter counting the number of pulses produced from the pulse generator output in the time interval between the pulses of the Start and Stop. This device has a higher stability and accuracy of conversion due to the fixation of a stop pulse at the center of the gravity. The accuracy of conversion and coding of information in a known device can be characterized by the variance of the random measurement error of the time interval through the variances of random errors that occur when the Start and Stop pulses are fixed, for which you can do the following ratio where 6 are the variances of the Start and Stop pulses, respectively . In the known device, due to the use of temporary fixation of the stop pulse in the center of the core, a decrease in the value of b is achieved, to the potential, i.e.

However, the pulse fixation is started at its leading edge, which leads to an increase in the variance of G with respect to its minimum (potential) value 0 d, -, i.e. (5 Considering this, the relation. (1) for the variance of the random error Interval measurements in a known device can be recorded as follows.

G iz 1 2 pot

7

Since for the known device G-Gp, it follows from relation (2) that in a known device it is impossible to achieve the potential possible accuracy of information conversion and coding, which is its disadvantage. In order to increase the nausea of measuring time intervals into a known device comprising a counter, a first trigger, two coincidence elements, a delay line, two adders, a comparison device and a pulse generator, whose stroke is connected to the first input of the first coincidence element, the second input and output are connected the output of the first trigger and the input of the counter connected by the output to the output of the device, and the first input of the second coincidence element is connected to the output of the comparison device, the two inputs of which are connected Through the first and second adders, respectively, with the first and second groups of leads of the delay line, the third and fourth elements of the match, the second trigger and the OR element, whose output is connected to the input of the delay line, the first input with the first inputs of the device and the second trigger, and the second the input is with the second inputs of the device and the second trigger, the first and second inputs of which are connected to the first inputs of the third and fourth elements of the match, respectively, connected by the outputs of the first and second, respectively m ttervogo trigger inputs, the second input - with the output of the second coincidence element, a second input coupled to a tap of the delay line tsentralnpi.

The drawing shows a structural diagram of the proposed time interval converter into a digital code.

The proposed transform;} s contains a pulse generator 1, a coincidence element 2, a trigger 3, a counter 4, an output 5 of the device, an element 6 of a coincidence, a 7 cp device, an adders 8 and 9, a delay line 10, an element OR 11, the first input 12 of the device trigger 13, the second device input 14 and the matching elements 15 and 16.

The device works as follows.

Pulse Start, arriving at input 12 of the device, through the element OR 11 enters the input of the delay line 10 n at the first input of the trigger 13, sets it to one state, during which a signal is generated at its first output that permits the signal passing through the coincidence element 15, coming in at his entrance. The samples of the amplitude of the Start pulse passing through the delay line 10 are fed from its first and second tap groups to the inputs of adders 8 and 9. Samples from the outputs of adders 8 and 9 are fed to the inputs of the comparator 7, where they are continuously compared. At the moment of equality of the weighted sum of samples of the values of the pulse envelope Start, taken from the output of adder 9, to the sum of the choice of values of the pulse envelope Start, taken from the output of adder 9, at the output of the comparator 7, a pulse is generated that passes through the coincidence element b (permission to pass this pulse gives the pulse itself Start, delayed to align the temporal relations in the delay line 10 and removed from its central tap) and the coincidence element 15 (permission to pass the pulse through the element coincides and 2 gives the signal from the first output of the trigger 13) to the first input of the trigger 3 and setting at its output a signal allowing the passage of clock pulses from the output of the pulse generator 1 to the input of the counter 4.

Counter 4 counts the number of clock pulses from the output of generator 1 pulses that have passed through element 2 of coincidence during the time interval during which the second input of element 2 of coincidence receives an enable signal from the trigger output. 3, with the reference point corresponding to the moment of fixation of the temporary position of the Start pulse, which is carried out by the delay line 10, the adders 8, 9, the comparator 7, and the coincidence element 6. The time of the end of the time interval when the trigger 3 is reset, prohibiting the passage of clock pulses from the output of the generator 1 pulses to the input of the counter 4, corresponds to the moment of fixing the center of the rod of the pulse Stop entering the device 14, while the pulse Stop sets the trigger 13 in the initial state, forming at its second output a signal permitting the passage through the element 16 of the coincidence of the pulse from the output of the element 6 of the coincidence.

At the same time, the Stop pulse through the OR 11 element is fed to the input of the delay line 10. At the moment of fixing the center of gravity of the Stop pulse, which is similar to fixing the center of the gravity of the Start pulse, a pulse is formed at the output of the coincidence element 6 passing through the coincidence element 16 to the second input trigger 3 and ystaIiavlivaIuschy on