SU1312519A1 - Device for measuring duration of time intervals - Google Patents

Abstract

The invention can be used to convert time intervals (TS) to a digital code. An introduction to the device for measuring the duration of the VI of the comparator 5, the prohibition element 6, the generator 4 of the linear-varying voltage, and the code-converter 3 is the voltage that increases the accuracy of the measurement of the VI. 2 Il. (/} I ate X Figure 1

Description

This invention relates to a technique for measuring time intervals and can be used to convert time intervals into a digital code.

The purpose of the invention is to improve the accuracy of measurement of time intervals.

FIG. 1 is a block diagram of the device; in fig. 2 - timing diagrams, but sleep; principle of operation of the device.

The device for measuring the duration of time intervals contains serially connected dynamic memory block 1, counter 2, code converter 3 - voltage, linearly varying voltage generator 4, comparator 5 and prohibition element 6 connected in series.

The device works as follows.

The measured time interval v in the form of a rectangular pulse {FIG. 2a) is fed to the input of the dynamic memory unit 1, which, for example, can be made on the basis of AND, OR, flip-flop, delay line and pulse amplifier elements.

The dynamic memory unit 1 provides periodic repeated reproduction of the measured time interval mx. In each cycle of reproduction with the pulse mx, the generator 4 of linearly varying naff is started (Fig. 26). Counter 2 is zeroed by the input pulse and the count of reproduction cycles is terminated. In proportion to the change of the code in the counter 2 — the output voltage of the converter 3 is changed; the code is the voltage. At the moments of equality of the output voltages of the generator 4 and the converter 3, the code — the voltage of the comparator 5 generates short pulses (Fig. 2c) ,. which arrive at element 6 of the ban. The prohibition element 6 provides “erasure of information about the measured interval in block 1 of dynamic memory.

Element 6 of the ban works as follows.

If the second input of the impulse bar mx 6 is present, the output pulses of the comparator 5 do not form a reset of the dynamic memory block 1, and in the absence of mx, the element 6 generates from the next pulse of the comparator 5 a reset signal of the dynamic memory block 1.

FIG. Figure 2 shows plots of voltages of convoluted signals from the dynamic memory block (Fig. 2a), from the output of the generator 4 linearly varying voltage, and a set of output voltages of the converter code - voltage (Fig. 26), convolution of the signals from the comparator output 5 (Fig. 2c) and the signal from the output of the prohibition element 6 (Fig. 2d). Period of reproduction of Tv mpulsov th block 1

dynamic memory must satisfy the condition

, „Ax + Tom + DT,

where tmaxmax is the maximum duration of the measured intervals; Top is the duration of the return stroke of the linearly varying voltage; DT - quantization step.

The slope of the linearly varying voltage and the magnitude of the unit increment of the DM output voltage of the converter code 3 - the voltage is selected based on the desired dT quantizer circuit. The duration T of the linearly varying voltage must satisfy the condition

T in T.1 Thmaks.

Consider the operation of the device in the N-and-th pulse reproduction cycle. Prior to this cycle, the pulses from the output of the comparator 5 coincided in time with the pulses Tx U, prohibition element 6 was closed. With each reproduction cycle, the output pulse of the comparator 5 approaches the trailing edge of the pulse m, by the magnitude DT.

In the Nth reproduction cycle, the output pulse of the comparator 5 goes beyond Tx (Fig. 2d), i.e. prohibition element 6 generates a reset signal and disrupts the TX reproduction process by the dynamic memory unit. So

as the number of play cycles N is counted by counter 2, then

mx N-dT.

Thus, the proposed scheme of the device for measuring the duration of time intervals allows

measurement with higher accuracy, practically independent of the instability of the reproduction period of the measured interval, and the quantization tag that determines the measurement accuracy can be

reduced to tenths of a nanosecond (at di 5 mV and the slope of the linearly varying voltage IB / 100 a tilt step of 0.5 is not obtained), which is not a limit for the proposed device and does not require critical operating modes of the elements used.

Claims (1)

Invention Formula A device for measuring the duration of time intervals, containing a counter, a block of dynamic memory, the input of which is also an input of the device, characterized in that, in order to improve accuracy, a co.parator, a bar element, a linearly varying voltage generator and converter code - voltage, the input of which is connected to the counter output, and output of the converter code - voltage is connected to the first input of the comparator, the second input of which is connected to the output of the generator of linearly varying voltage, and course Ll Gh the comparator is connected to the first input of the prohibition element, the output of which is connected to the second input of the dynamic memory unit, the output of which is connected to the counter input of the counter, the generator input of the linearly varying voltage and the second input of the prohibition element, and the installation input of the counter is connected to the input of the device. Z L Lxr LT1 723 ...  fj 7 1 i 1 (V yy-7 2 / Y