SU467288A1 - Device for tolerance control of transient frequency setting time - Google Patents

Description

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The proposed device relates to the field of aiBTOMaTH4ecKoro control and can be used in the construction of systems for controlling the dynamic parameters of various objects in the time domain, for example, linear integrated circuits.

Known devices for the tolerance control of frequency, containing three pulse counters, a logic circuit and a frequency reference generator.

The disadvantage of such devices is that with their help it is impossible to control the tolerance of the duration of the transient frequency setting process, and only the established frequency can be compared with the reference frequency.

The aim of the invention is to increase the reliability of the control.

This goal is achieved in that the device additionally contains an anti-coincidence cell, whose input is connected to the output of the reference frequency generator, a reversible counter, the control inputs of which are connected to the outputs of the anti-coincidence cell, and a reset input — with the output of the third counter, trigger, the first input connected to the output a reversible counter and a reset input of the first counter, and a second input, 5 - with the output of the third counter, and a matching cell, connected by the first input with the trigger output,

the second input - with the output of the third counter, and the output - with the input of the first counter. The drawing shows a block diagram of the device.

The device consists of a cell anti-coincidence 1, a reversible counter 2, trigger 3, the first pulse counter 4, the generator 5 of the reference frequency, the second pulse counter 6, the third pulse counter 7, the cell

match 8 and logical cell 9.

The device works as follows. The anti-matching cell 1, pre-assigned to prevent reversing counter 2 fails, the frequency fx under test and the reference frequency fax are fed to the summing and subtracting inputs of the reversing counter 2. The pulses coming from the generator 5 of the reference frequency through the counter of pulses 7 to the reset input of the reversing counter 2 are set accumulation intervals, during each of which in the reversible counter 2 a number proportional to the average difference frequency is accumulated. At the beginning of the transition process, when the difference of the studied and reference frequencies is still quite large, the reversible counter 2 has time to overflow several times during the accumulation interval. The overflow pulse of the reversible counter 2 is fed to the reset input of the pulse counter 4, and also sets to one

trigger state 3. The latter triggers a coincidence cell 8 for the pulses from the output of pulse counter 7 to the input of pulse counter 4. In the transition process of establishing the frequency under study, the difference between the last and reference frequency is reduced. There comes a time when this difference does not exceed the permissible value. The capacity of the reversible counter 2 is chosen in such a way that, if the average difference frequency is equal during the accumulation interval and the allowable difference frequency, the maximum number accumulates in the reversing counter 2 (i.e. it reaches overflow once per accumulation interval).

With a further decrease in the difference frequency, the reversible counter 2 for each of the subsequent accumulation intervals will no longer overflow, i.e. there will be no overflow pulses at its output. This means that the trigger 3, which is set to the zero state by a pulse from the output of pulse counter 7, does not change after the next accumulation interval of its state, and the next pulse from the output of pulse counter 7 passes through a coincidence cell 8 to the input of impulses counter 4 .

In the following accumulation intervals, everything happens in a similar way.

The pulse counter 4 is used to increase the reliability of the device with the oscillating damped nature of the transition process. In the case of a monotonic transient, the pulse counter 4 may be absent. When the last pulse arrives at the input several times it overflows, indicating that during the time determined by its capacity and the duration of the accumulation interval the difference frequency did not exceed the tolerance limits. The output pulse of the pulse counter 4 is fed to the input of the logic cell 9. The pulse counter 6 starts counting at the moment of the beginning of the transient process, counting the pulses of the generator 5 of the reference frequency, i.e. it is a time sensor.

8 moment of time corresponding to the maximum duration of the transition process, the pulse counter 6 outputs to the logical cell

9 impulse (i.e., the tolerance of the duration of the transient process is set by means of a pulse counter 6). Logic cell 9, depending on the order of arrival of pulses from pulse counters 4 and 6, generates a signal

"Good or not good." If the first impulse comes from the output of the pulse counter 4, then the duration of the transient process is less than permissible and logical cell 9 generates a “Fit. Otherwise -

"Unfit.

In order to automatically control the dynamic parameters of linear microcircuits using the proposed device, such as rise time and output voltage setting time, delay time, etc., the output of the microcircuit must be connected to the input of the proposed device through a voltage converter (or other required quantity) in frequency.

In order to automatically control the time to enter the generators and frequency sensors, the proposed device can be used directly.

Subject invention

Device for tolerance control of transient frequency setting time, containing the first counter, the output of which is connected to the input of a logic cell, the second input of which is connected to the output of the second counter, connected to the reference frequency generator, which is connected to the input of the third counter, different

in order to increase the reliability of control of the device, it contains an anti-coincidence cell, the input of which is connected to the output of the reference frequency generator, a reversible counter, the control inputs of which

are connected to the outputs of the anti-coincidence cell, and the reset input is connected to the output of the third counter, a trigger, the first input connected to the output of the reversible counter and the reset input of the first counter, and the second input -

with the output of the third counter, and a matching cell connected by the first input to the trigger output, the second input to the third counter output, and the output to the input of the first counter.