SU285104A1 - - Google Patents

Description

METHOD FOR REGISTRATION OF THRESHOLD FREQUENCY

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The invention relates to the field of automation of production processes and to find application in automatic control and management devices, for example, in relay-type radioisotope devices.

A known method for detecting a threshold frequency by converting a pulse frequency into a voltage and then comparing this voltage with a voltage corresponding to a threshold frequency value.

The disadvantage of this method is its inertia, which is especially manifested at a low threshold frequency.

The present proposal makes it possible to reduce the time of registration of the threshold frequency.

This goal is achieved by forming imiums, the duration of which is equal to the period of the pulses of the threshold frequency, merging into one coincidence pulse when the frequency of the initial sequence of imiuls becomes more than the threshold frequency. At the same time, the duration of each generated pulse is converted into a voltage.

The invention is illustrated in the drawings, where in FIG. 1 shows a block diagram of a device implementing the proposed method, and FIG. 2 - pulses of the original frequency sequence, generated pulses and control voltage signals.

The device consists of a pulse shaper 1, a pulse converter 2, and a relay element 3.

Work, the device is as follows.

If the frequency of the original pulse sequence is less than the threshold frequency, then when these pulses arrive at the input of the pulse former 1, threshold pulses are formed, the duration of which is equal to the time interval between two adjacent threshold frequency pulses.

The pulse converter 2 converts the pulse duration into a proportional voltage, which, however, does not have time to reach the threshold voltage for the duration of the threshold pulse. Increasing} P1e frequency of the original pulse sequence leads to a decrease in the time interval between the formed poro1Ov.mp pulses.

When the frequency of the original pulse sequence reaches the threshold frequency, threshold pulses merge and an imitation of coincidence is formed, the duration of which is determined by the time during which the frequency of the initial pulse sequence is strictly equal to or greater than the threshold pulse.

If, in this case, the control voltage produced by the pulse converter 5 reaches the threshold voltage Un, the relay element 3 will be triggered.

As soon as the frequency of the original pulse sequence becomes less than the threshold, the pulse coincidence will form. The control voltage will become zero and the relay element 3 will turn off.

The registration time tf can be adjusted by changing the threshold voltage f / n at which the relay element is triggered, and also by changing the slope of the control voltage curve.

The minimum registration time in the ideal case is equal to the duration of the threshold pulse. However, almost minimal

the recording time should be set taking into account possible fluctuations of the time intervals between pulses of the detected threshold frequency.

Subject invention

A method for detecting a threshold frequency, characterized in that, in order to reduce

registration time, from the original frequency sequence form pulses whose duration is equal to the period of the pulses of the threshold frequency, merge into one pulse of coincidence, when the frequency of the original pulse sequence becomes longer than the threshold, the duration of each generated pulse is converted into a voltage.

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