SU980062A1 - Time interval measuring method - Google Patents

Description

(54) METHOD OF MEASURING TIME INTERVALS

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The invention relates to radio-measuring technology and can be used in measuring time intervals of the nano- and microsecond ranges.

There is a known method of measuring time intervals by gating a time-shifted gate pulse with these gates, forming signals corresponding to the beginning of tf) and the end of t | interval, counting the number of pulses that are synchronous with the strobe and fill interval 1.

The closest to the present invention is a method for measuring time intervals by gating these intervals with a time-shifted gate pulse, fixing sigHfuiOB, controlling the gate-shift shift and the corresponding time coordinates of the coincidence moments. building a pulse with a dot gate signal corresponding to the reference levels of the beginning t and the end t of the measured interval time, and determining the measured value as the difference between the fixed coordinate values 2.

The known methods are characterized by low measurement accuracy due to the non-linearity of the shift of the gating pulse and the instability of the scale factor in the measurement range.

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

This goal is achieved according to the method, in which, they generate / rut, respectively, fixed coordinates tn and t. signals with periods of + toH T ,, tK + to g and the measured value is determined by the difference of these periods, where the to-constant value determined by the measurement conditions.

The drawing shows a block diagram of an apparatus for carrying out the proposed method.

The device contains a gated converter of 1 signals, a shaper of 2 gating pulses, a block

3s shifting gating pulses, block

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4 controls and a 5 period difference measurement unit.

A pulse signal that contains the measured time interval (for example, measures the duration of the pulse front, 30 ° C | switched between some first and

the second reference level), is fed to the measuring input of the device and then to the input of the gated signal converter 1.

Simultaneously with some advance determined by the value of the initial delay in the strobe shift unit 3 (Dusting pulses, a sync pulse arrives at the synchronization input, which triggers the control unit 4, which generates a control signal for the gating pulse unit 3. In accordance with the control signal, a time shift is made arriving at the input of block 3, the shift of the clock pulses of the sync pulse.

From the output of the gating pulse shift unit 3, the gating pulse shaper 2 is launched, issuing a gating pulse normalized in amplitude and duration to the gated signal converter 1, where the instantaneous value of the input signal is compared at the time the strobe pulse arrives with the first count level from the control unit 4.

The result of the comparison is fed to the analysis in control unit 4. According to the analysis result, the time shift control signal of the gating impulse is generated, which provides the approach of the current time coordinate of the gating pulse to the desired coordinate of the beginning of the measured time interval tn / corresponding to the intersection point of the first reference level with the front of the pulse signal containing the measured interval.

The search for the coordinate t is carried out for n cycles corresponding to n periods for the repetition of the clock pulses.

When the current time coordinate of the gating pulse coincides with the 1c coordinate (which is indicated by the corresponding signal from the output of the gated signal converter 1) in the control unit 4, the coordinate search mode is interrupted, the signal controlling the shift of the gating pulse and the gating pulse shift unit 3 are fixed at this coordinate transferred to the self-oscillation mode, and it generates a signal with a period of + to, where to is the delay in the feedback ring of the gate 3 shifting pulse unit in the self-oscillating mode. This signal is fed to the period span measurement unit 5, where T is measured and the measurement result is stored.

At the end of the measurement T с from the block 5 for measuring the difference of the periods, the control block 4 receives a signal to continue measuring. By this signal, the gating pulse shifting unit 3 is transferred from the self-oscillating mode to the gating pulse shifting mode, and the control unit 4 is transferred to the tK coordinate search mode, which is the intersection point of the input signal with the second reference level embedded in this mode from the control unit 4.

The search t, generation and measurement of Tc t c + to is performed similarly as described for Next and in block 5 for measuring the period difference, TK-TH to-H + T) t (t-tn) is determined, which is the result of measuring the time interval.

Improving the accuracy of the measurement of time intervals is provided by the exclusion of the error components due to the nonlinearity of the shift of the gating pulses and the instability of the scale factor in the measurement range.

Claims (1)

1.R Binin Yu.A., Stroboscopic oscillography. M., Soviet Radio, p. 228-230. 2, USSR Author's Certificate No. 536441, cl. G 01 R 19/26, 1975.