SU966616A1 - Device for measuring pulse repetition mean frequency - Google Patents

Description

The invention relates to electrical measuring equipment and is intended to measure the frequency of pulses in packs. A device for measuring the carrier frequency of radio pulses is known, which contains a pack detector, a trigger, two selectors at the inputs of counters, a measured and reference frequency, an OR element, a sumator l.

However, the measurement time in a known device is variable, which reduces the speed of the device when working with a signal with a high duty cycle.

The closest in technical essence to the present invention is a device comprising a pulse generator of a reference frequency, two counters and two selectors, a divider frequency and a trigger 2.

The prior art device makes it possible to measure the average frequency of continuous signals and the average frequency of a burst, but provided that the repetition period of the burst is longer than the measured measurement time. For the case when the duration of a burst is less than the measurement time, the device provides for the measurement of the time when there is no signal at the end of the measurement.

A significant disadvantage of this device is that if the period of the following pulse train turns out to be shorter than the fixed measurement time, the result of measuring the average frequency of the pulse train will be wrong, since the pause

10 between bursts of pulses will not be taken into account.

The purpose of the invention is to enhance the functionality and improve the accuracy of measuring the average pulse frequency.

Claims (2)

This goal is achieved in that a device for measuring the average pulse frequency, containing a pulse generator of 20 lon frequency, connected through a first selector to a frequency divider, the output of which is connected to the reset input of the first trigger, and the output of the first trigger is connected to the control inputs the first and second selectors, the outputs of which are Connected respectively to the inputs of the first and second pulse counters, the input of the second selector is connected to the set input of the first trigger and the device input Twa administered serially connected tpiggep second AND gate and a third counter, wherein the input RRF sa second flip-flop and its input FITTING ny respectively connected to the output of the second selector and the output of the first counter and the second input of the element and connected to the output of the first selector. The drawing shows a block diagram of the device. The device contains a generator of 1 pulses of the reference frequency, trigger 2, selectors 3 and 4, divider 5, counters 6 and 7, trigger 8, element I, and counter 10. Frequency measurement starts after zeroing divider 5 and counters 7 and 10 (zero circuit shown) Pulses of the measured frequency are delivered to the input of the selector 4 and to one of the control inputs of the trigger 2. The first pulse of the measured frequency transfers the trigger 2 to the Start state, at which the selectors 3 and 4 open and to the counter 7 serves pulses the measured frequency, and on the divider 5 - the pulses are the reference The second hour of the generator 1 through the open selector 3. The filling of the divider 5 and the counter 7 begins simultaneously (with an accuracy of one period of the reference frequency) and continues throughout the entire measurement time. That / i.e. before the appearance of a pulse at the output of divider 5, which then enters the second control input of trigger 2 and puts it in the Stop state. At the trigger output, a signal appears that locks the selectors 4 and 3. Counter 6 is zeroed by each pulse of the measured frequency, and trigger 8 is set to the state O. By connecting the control input of the trigger 8 to the corresponding output of the counter 6, the maximum counting number N pulses of the reference frequency fgt is specified. the measurement time is greater than the time T. At the output of the counter 6, a signal appears that switches the trigger 8 to the open state of the ment 9, and the reference frequency pulses start They arrive at the counter 10, counting the pause time. If a batch of measured pulses appears again, the counter 6 is zeroed, the trigger 8 goes to the state O and closes the element AND 9. The pulses of the reference frequency no longer reach the counter 10. When the input signal disappears again, the pause measurement process will be repeated and added up. in the counter 10. After the expiration of the measurement time Tp, the total time of pauses Tp between the bursts of pulses during the measurement time can be determined from the readings of the counter 10 (taking into account the switching on of the counter 10) the number of (total periods to their total duration N - (K + 1) where Wy - counter readings 7j K - the number of trigger inclusions 8. The technical effect of the invention lies in the fact that due to an accurate measurement of the total duration of an integer number of periods of the measured frequency and the total duration of the pauses between bursts of pulses exceeding a predetermined value increases the accuracy of measurement, and also the functionality of the device, i.e. for a fixed measurement time and with a given accuracy, one can measure not only the average frequency of continuous signals and the average frequency of impulses in the packs, but also determine the number of packs and pauses, as well as measure the well bore of packs. The invention The device for measuring the average pulse repetition frequency, containing a reference frequency pulse generator, connected via a first selector to a frequency divider whose output is connected to the reset input of the first trigger, the output of the first trigger is connected to the control inputs of the first and second selectors, the second selector input is connected The installation input of the first trigger and the input of the device are the outputs of the selectors connected to the inputs of the first and second pulse counters, respectively, , P. in order to expand the functionality and improve the measurement accuracy, a second trigger, an AND element and a third counter are introduced in series into it. moreover, the reset input of the second trigger and its installation input are connected respectively to the output of the second selector and the output of the first counter, and the second input of the element I is connected to the output of the first selector. 9666 5 66 Sources of information taken into account in expert studies: r1, USSR Copyright Certificate No. 773514, cl. G 01 R 23/10, 1978. 2. Authors certificate of the USSR 524139, cl. G 01 R 23/02, 1976.