SU447635A1 - Digital frequency meter - Google Patents

Description

(54) DIGITAL FREQUENCY

one

The invention relates to the field of automation and information and measurement engineering and is intended to automatically measure the instantaneous frequency value with the output of the measurement result in a digital code, suitable for input into an electronic digital computer.

By bus No. 350167 is known for a digital frequency meter comprising a serially connected frequency generator, a pulse frequency generator of a reference frequency, a key and a counter, as well as serially connected pulse generator of a measured frequency, a second key and a second counter, a control trigger and a matching circuit.

However, the known device measures the average value of the frequency rather than the instantaneous value.

The purpose of the invention is to provide an indication of the magnitude of the frequency.

This is achieved by the fact that the device is equipped with an electronic-vernier circuit.

The drawing shows a block diagram of the proposed device.

GlpdJ aga ty frequency meter contains a coincidence circuit 1, keys 2 and 3, shaper 4 pulses of measured frequency, generator 5 standard frequency, shaper 6 pulses of reference frequency, tr1pter 7, counter 8 coarse counting, block 9 of electronic vernier, which includes a trigger 10, an impact excitation generator 11, a coincidence circuit 12, and an exact count counter 13.

The device works as follows.

Matching circuit 1 and pulse -ndand keys 2 and 3 are given two, pulse sequences, one from the driver 4, which converts the input frequency voltage) (to a sequence of pulses with a repetition period Tj), and the other from the generator

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standard frequency 5 and shaper

6 - with a period of T -,

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At the first coincidence of impulses of unknown and standard frequency, the coincidence circuit 1 impresses them on control trigger 7, which opens keys 2 and 3. Counter 8 receives impulses at the frequency level; the second input i of trigger 7 does not receive the second input coincidence. unknown frequency. ; Trng 7 is overturned, making it the same for standard pulses. counter 8. But at the same time, jTOg shyntn manages it through the key 2 tK & the input of block 9 of electronic noniCa (one of the inputs of trigger 10). Trigger i 10 starts the generator 11 with an excitation condition, the frequency is equal to k, where a is the basis of the received number unit; k is a chain number. The pulses of the generator 11 are counted by a precision counter and simultaneously arrive at the coincidence circuit 12, the second input of which receives pulses of the stagartal frequency. At the time of coincidence in circuit 12, an impulse is removed from the output 12 Counter 8 is fixed code Nf. and in the counter 13 h | j, which links the measured period; T is the period of the standard frequency 1; t by the relation i; f VWp - c; . CT cr X k CJt Division by a is made by transferring a comma in the 1P code. Subject of the invention Digital frequency meter according to the author. Mg 35016 O tl and h to the extent that, in order to measure the instantaneous value of the frequency, it is equipped with an electronic vernier circuit, k | the first code of which is connected forming | tel pulses the reference frequency, and k X the second output of the second key.

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