SU446842A1 - Device for generating a measurement interval for digital frequency meters - Google Patents

Description

one

The device relates to the field of electrical measuring equipment.

Devices are known for generating a measurement time interval for digital frequency meters, comprising a reference frequency generator, a time counter, a comparison circuit, a key, and a trigger.

The proposed device differs from the known one in that, in order to simplify its construction, the beginning of the time interval is determined by the falling edge of the pulse taken from the output of the And, and. ends with a pulse removed from the output of the time counter. In this case, in the interval between measurement intervals, work is blocked, for example, the second decade of the time counter, and during the formation of the measurement time, the formation of pulses at the output of the "I.

The structural scheme of the described device is shown in the drawing.

The device contains a generator of 1 exemplary frequency, a decade of 2, 3, and 4 time counters, a trigger 5, and an AND 6 circuit.

The operation of the device is as follows.

The frequency pulses / o from the generator output are fed to the input of a time counter (decades 2, 3 and 4). If the trigger 5 is in the state "1", the formation of a pulse at the output of the circuit 6 is allowed and the operation of the decade 3 is blocked. At the same time, the decades 3 and 4 are in the zero state. At the moment of transition of decade 2 from the state "9 to the state" About the trigger 5 is set to the state "O. The formation of a pulse determining the measurement time ta is started. At this moment, all decades of the counter are in the state "O" and, therefore, the signal at the output of the time counter, which returns the trigger 5 to the initial state, having completed the formation of the measuring interval, is determined by the frequency period fo and the capacity of the time counter.

At the moment of the beginning of the formation of a pulse of duration t, the zero potential is removed from the input of the first trigger of decade 3 and the operation of decade 3 is resolved. At the same time, the formation of a pulse at the output of the "And 6" circuit is blocked.

The installation of the < 6 > circuit at the output of a decade of a time counter is determined by the required speed of the device for which the present device is used.

Subject invention

A device for forming a measurement interval for digital frequency meters, comprising an exemplary frequency generator, a trigger and a time counter, characterized in that, in order to simplify the construction of the device, it is equipped with an AND circuit that monitors the state of "9 ONE decades of the time counter, the reference frequency generator is connected to the input of the first decade of the time counter, one of the outputs of the trigger is connected to the first input of the “And,

The second input is connected to the output of the first decade of the time counter, which monitors the state "9, the output of the circuit" AND is connected to one of the trigger inputs, another input of the trigger is connected to the output of the time counter, the second output of the trigger is connected to one of the inputs of the second decade of the counter of time.