SU960721A1 - Device for measuring time intervals - Google Patents

Description

(54) DEVICE FOR MEASURING TEMPORARY

INTERVALS

one

The invention relates to a measurement technique and can be used to accurately measure reproducible time intervals.

A device for measuring time intervals is known, which is built on the principle of statistical averaging the results of intermediate measurements, performed methods for directly filling the measured interval with reference frequency pulses and nx counting, contains an OR element, a switch, a trigger, a coincidence element, a generator, a variable frequency divider, a block fbr-: world variable delay, unit for measuring the average value of the period U - l However, the following shortcomings are inherent in this device: a large number of intermediate measures The measures necessary to ensure a given accuracy of the final result; large volume. ore; the impossibility of obtaining a final measurement result without additional calculations.

The closest in terms of technical sufficiency to an inventive device is a device that contains two quartz shkh clock generator with close frequencies, a beat frequency generator, a frequency divider by two, a D-flip-flop, a selector, a count :, an indicator and a control node. This device has high accuracy and resolution, which are achieved due to the proximity of the clock of the generator, high stability

 in the work, due to the use of as a clock generator of quartz oscillators operating in a continuous mode.

.

A disadvantage of the known device is a small range of measurement intervals. The range of measurements of this device is limited by the duration of the period of the pulse of one of the quartz oscillators. In the case of a simple increase in this period, the dimension of the measurements increases proportionally. 3660 The purpose of a juvenile is to expand the range of measurements of time intervals without degrading the accuracy of measurements. The goal is achieved in that, in a device for measuring time intervals, containing the first and second quartz clock pulse generators, D is a trigger, the clock input of which is connected to the output of the second quartz clock pulse generator and to one of the selector inputs whose other input is connected with the output of the trigger, and the output with the counting input of the counter, the outputs of which are connected to the first input of the display unit, the control unit, the first output of which is connected to the installation input of the counter, is additionally entered U-flip-flop, selector, divisor with variable division factor, start-up unit, 1 9-flip-flop and measurement number counter, the output of which is connected to the input of the control unit, the second input of which is connected to the second input of the display unit of the connection unit with T) the input of the additional D flip-flop, the clock input of which is connected to the output of the first quartz oscillator of clock pulses and the first input of the additional selector, the input of which is connected to the output of the additional D-flip-flop, the P input of which is connected to the setting input One counter of the number of measurements and the start-up unit and to the first input of the control unit, the output. An additional selector is connected to the input of a frequency divider with a variable division factor, the output of which is connected to the S-input of the R5 trigger and the input of the measurement object whose output is connected to the 1-input of the IS-Trigger whose output is connected to the counting code of the meter number and O -in the input of the main 3) trigger. FIG. 1 shows a block diagram of a device for measuring time intervals and intervals; in fig. 2 - broken diagrams for his work. The device for measuring bp @ 1 intervals contains the first quartz oscillator 1 clock pulses, additional p-trigger 2, additional cJSKTOp 3, deductor 4 frequencies with variable division factor, trigger 5, counter 6 of the measurement, block 7 start, containing button 8 and R5-trigger 9, control unit 10, second quartz oscillator 11 clock pulses, basic 1, 4 D-flip-flop 12, main selector 13, counter 14 and display unit 15, Pulse periods of the generators 1 to 11 are selected from the condition of the vernier conversions, for example T1 (I-C) u2 where VI - number of rows HafypanbHoro h 1,2, ....; T. - the period of the following pulses of the generator 1; f is the period of the pulse of the generator 11. In the proposed device, the linear law of phase modulation of the occurrence of starting pulses relative to the divisions of the series formed by the pulses of the generator 11 is implemented. The division factor K of the divider 4 times cannot be arbitrary, tC) L: rz1 -1, (2) where OI "1,2 ...; . C, is the base of the number system, 0,1,2, ...; TO. a pulse following period of the second generator 11; T, is the period of the following pulses of the first generator 1, and the conversion factor M of the counter 6 of the number of measurements is selected from the ratio. where and - the number of intermediate measurements in one full dimension; e is the interpolation step of the period of the second quartz oscillator of clock pulses, equal to the device's resolving powers. The device for measuring time intervals works in the following way. In the initial state, all the counters are reset to zero, the triggers are set to zero, the arrival of the starting pulse from the button 8 sets the R9 trigger 9 to the single state, and a positive voltage drop arrives at the D input step-trigger 2. After that, the first impulse coming from generator 1 to the clock input of p-trigger 2, in its increasing front, translates it into a single state. As a result, the selector 3 opens and the pulses from the oscillator 1 are fed through the open selector 3 to the input of the divider 4 frequencies with a variable division factor.

The first impulse from the output of the divider 4 as a starting pulse arrives at the input of the measurement object and at 5 - the input R of the 5-flip-flop 5, which sets it into a single state. A positive 5 voltage across the output of the trigger 5 enters the 1 input 1-trigger 12 — the trigger 12 overturns by the rising front nefaoro of the same pulse received after this moment from the output of the generator 11. The pulses of the generator 11 go through the selector 13 to the counter input 14, where it is calculated.

The impulse Stop formed at the output of the measurement object arrives at the R input of the trigger 4 and puts it in the zero state. The negative voltage jump from the output of the trigger 5 is fed to the WE-input of the D-trigger 12 and the very first moment after this moment, the pulse front of the generator 11 Perevo. It triggers 12 to the zero state, stopping the pulse generator 10 input to the counter 14 using the selector 13, the negative differential from the trigger trigger 5 goes to the measurement chiol counter 6 and is recorded in it as a count.

The first intermediate measurement ends.

With the arrival of the next pulse from the output of the 4-frequency divider, the whole cycle is ampli fi ed. Moreover, the measurement results of each cycle are summed up in counter 14, and the phase of the starting pulse in each E5 of the new cycle is mixed along the graduations of the scale formed by the leading edges of the generator pulses 11 to the . pol ats d t1-t2. This step determines the resolution 40 of the device, thanks to the fulfillment of relations (1), (2), (3) by the time the i-th pulse arrives from the output of the divider 4, the start-of-pulse phase pulse will pass all AND of the values on the period T2 of the generator 11 would be broken.

With the arrival of the I-th pulse from the output, divide 4 the counter 6 of the number of L Л measurements and the impugue from the overflow enters the control unit 10, which first generates a census error

and the number fixed in the counter 14 is rewritten into the display unit 15, and then the installation pulse is generated, which triggers and the counters triggers.

The number recorded in block 15 is the result of the measurement. When you press button 8, a new measurement will occur. If, however, the R-input of RC, Trigger 9 is disconnected from the reset output of the control unit 10, then the measurements will automatically be repeated with a period set by the frequency of the generator 1 and the division factor K of the divider 4 frequencies.

Time diagrams are constructed in accordance with relation (2).

The diagram (Fig. 2) shows the pulses of the generator sequence 11 (Fig. 2a), the generator 1 (Fig. 26), as well as the measured pulses generated by the RS flip-flop 5 (Fig. 2c) for several consecutive measurement cycles. . The coincidence of the pulse fronts of the generators 1 and 11 at the beginning of the measurement is conditional.

The fronts at the beginning of the measurements can be in an arbitrary position relative to each other. The result of the final measurements will not change. Therefore, a beat frequency generator and a beat frequency divider and a frequency divider by two are excluded from the device.

In contrast to the known device, along a measured pulse (formed by trigger 5), not one front of the generator pulse II slides, but a number of edges. Moreover, the number of pulses in a row depends on the duration of the measured interval, and from cycle to cycle in one dimension may differ by one unit. If the measured pulse has a duration of -fcy T2. that the number of fronts of the generator pulses 11, coinciding with him in time, And 1 or m O, that is, while the proposed device realizes the situation that occurs in the known device, as a special case.

If, in a known device, the duration of the pulse being measured is limited to T2, then in this device such a restriction is removed by introducing divider 4 and counter 6 into it, and connecting the input of the measurement object to the divider 4.

The duration of the time interval measured by this device can be practically any, depending on the needs of a particular application.

Claims (2)

The device control unit may include two delay elements connected in series. From the output of the first delay device, a signal is copied from the counter 14 7 to the block 15, and from the output of the second element of the eaderiosi, the setting signal. In this way, the proposed device for measuring time intervals can be able to accurately measure temporal visibility over a wide range of input durations. Due to this, a significant amount of & peni expands the field of application of the device, for example, it can be used to measure for objects up to motionless or at low speed objects, to control the temporal parameters of paired impulse generators, operating in external trigger mode, & dividing the metrological characteristics of delay lines, Range imitators, and tl. Claims of the Invention A device for time integrals containing the first and second clock generators, a D-trigger, the clock input of which is connected to the output (W {of the second crystal oscillator. Clock pulses and one of the selector inputs, the other input of which is connected to the output B is a trigger, and the output is a counting input counter, the outputs of which are connected to the first input of the display unit, the control unit, the first output of which is connected to the installation input of the meter, so that for the purpose of advanced Depending on the measurement range of time intervals without deterioration of measurement accuracy, a D-trigger, a selector, a divider with a divide division factor, a start block, a trigger and a measurement number counter, the output of which is connected to the input of the control unit whose second output is connected to the second, are added to it the input of the display unit, the output of the start-up unit is connected to the X input of an additional E-trigger, the clock input of which is connected to the output of the first quartz oscillator of clock pulses and the first input of the additional selector, the second input of which is connected to the output of the additional U - trigger, the input of which is connected if. To the installation inputs of the measurement number counter and the start-up unit and to the first output of the control unit, the output of the additional selector is connected to the input of the frequency divider with a variable division factor, the output of which is connected to the 5th input of the R5 trigger and the input of the measurement object whose output is connected to The R-input of the WS-trigger, the 1st input of which is connected to the counting input of the counter of the ID number and the E-input of the main p-trigger. Sources of information taken into account when the expert 1. The author's certificate of the USSR № 679928, cl. G O4 F 1O / O4, 1979. 2. US patent number 4.168467, cl. i8 O4 F 10 / O4, 1979. And j Y