SU560185A1 - Digital frequency meter - Google Patents

Description

8 pulse generator of the measured frequency, which converts the input voltage frequency / x into a sequence of pulses with

-. In addition, the same postperiod -;

fx

The remoteness arrives at key 9. The outputs of the match element 3 and the additional match element 5 are connected to the input of the trigger 10, and the output of the additional match element 5, in addition, to the input of the additional trigger 11.

The outputs of these flip-flops are connected to the inputs of the anti-matching element 4 and the additional matching element 6 in such a way that the anti-matching element 4 opens upon receipt of a single potential from the trigger 10, and zero from the additional trigger 11. The additional match element 6 opens upon receipt of unit potentials from both triggers.

The first match pulse from the output of any of the elements 3 and 5 is the trigger 10, which leads to the opening of the anti-coincidence element 4, if this pulse is from the match element 3, and the additional match element 6, if it is from the additional match element 5. In the latter case trigger 11 is thrown. Key 9 opens anyway.

In the counter 21 connected to the output of the switch 9, the counting of pulses of the measured frequency begins, and in the counter 13, the input of which is connected to the outputs of the anti-coincidence element 4 and the additional coincidence element 6, the reference frequency is counted.

The second match in one of the elements 3 and 5 counts the pulses, and if the second match occurs in the other match element, since after switching over the trigger 10, the trigger 11 remains in one state, at the output of the additional match element 7, whose inputs are connected with the outputs of the triggers, a single potential is formed, which comes in an additional bit (the first character after the commanding) of the counter 13, recording the number 5 there (in the decimal number system).

The measurement result is determined by determining the ratios of the codes AH and Au, recorded respectively in counters 12 and 13:

g - - f A,

The formation of the code of the main bits of the counter 13 depends on the speed of the triggers 10, 11 and elements 4 and 6. TO

If it is less

then the pulse shifted relative to the match by -7 is not counted in the counter 13, and the code of the main bits used for the determination of x is equal to the number of counted pulses n.

T

If it is more, the shifted pulse is counted, and then the code is n-1. This case is more preferable in comparison with the first one, since the speed of the elements of the frequency meter is determined by the period value of the highest frequency x and / o.

The proposed frequency meter can reduce not only the waiting time for the first match, but in general, the pulse counting time by counters.

Claims (1)

Inventive Formula A digital frequency meter containing serially connected exemplary frequency generator, driver, match element, trigger, key and counter, as well as an additional counter and pulse generator of the measured frequency, the outputs of which are connected to one of the inputs of the match element and key, differing in that, in order to increase speed, it is equipped with an additional trigger, an element of anti-drops and three additional elements of coincidence, the inputs of the first of which are connected to the outputs of the formers, and its output - to the inputs of the triggers, the inputs of the second additional element of coincidence are connected to the outputs of the former and the triggers, and its output is connected to the input of an additional counter, the inputs of the third additional element of coincidence are connected to the outputs of the triggers, and its output is connected to another input of the additional counter, the inputs are Anti-coincidence enta is connected to the outputs of the triggers and the driver, and the output is connected to the entrance of the additional counter.