SU855521A1 - Device for tolerance frequency control - Google Patents

Description

(54) DEVICE FOR ADMISSION CONTROL The invention relates to a control measurement technique and is intended to indicate the output of a monitored frequency beyond a predetermined tolerance in devices for automation, radio electronics, and telemechanics. known devices for frequency control, containing two delay lines, an OR element, four AND elements, four NOT elements, two decoders, five indicators, six limit triggers, the controlled frequency terminal being connected to the same input of the first pulse counter and through the delay line with input house zeroing pulse counter I terminal of the reference frequency from the line with the counting input of the second pulse counter, and through the second delay line with the input zeroing of the first pulse counter, the outputs of which are connected y are to the inputs of the first decoder, and the outputs of the second pulse counter are connected to the inputs of the second decoder, the outputs of the first decoder are connected to the single inputs of three triggers, the zero inputs of which are connected to the reference frequency terminal, the outputs of the second decoder are connected to the FREQUENCY unit of the three other triggers , the zero inputs of which are connected to the controlled frequency terminal, the outputs of the flip-flops via the AND, OR gates are NOT connected to the Cl3 indicators. The disadvantage of this device is a large amount of equipment and, as a result, reduced reliability. The closest to the proposed invention is a device for frequency tolerance control, containing two pulse counters of controlled and reference frequencies, the inputs of which are connected via keys to the inputs of the controlled f and the reference f frequencies j control trigger, a single input of which is connected to the output of the synchronization circuit, and the output is with control inputs of keys. One input of the synchronization circuit is connected to the input of the controlled frequency, and the other input is connected to the Start control input. The output of the counter is connected to one of the zero inputs of the control trigger, which is also the first output of the device. A trigger is connected to the output of the pulse counter of the reference frequency, the single output of which is connected to the inputs for setting the counter of the reference frequency, is the second output of the device, and the zero output of the trigger (the third output of the device) is connected to the zero input of the control trigger G21.

A disadvantage of this device for frequency control is a large amount of equipment and low reliability.

The purpose of the invention is to increase the reliability of the device.

The goal is achieved by the fact that a pulse counter and a series-connected AND element and a locking element, the second input of which is connected to the output pulse of the reference frequency pulse, are inserted into the frequency tolerance control device containing a reset unit, the output of which is connected to the pulse counter inputs of the monitored and reference frequencies, to the input of the pulse counter and to the first input of the element I, the second input of which is connected to the output of the pulse counter of a controlled frequency, while the second input of the pulse counter owls connected to the output of the reset unit, the input of which is connected to the output of the pulse counter.

FIG. 1 shows a block diagram of the device; in fig. 2 and 3 are timing diagrams for the operation of the device.

The device tolerance control frequency (see Fig. 1) contains counters 1 and 2 pulses of the reference and controlled frequencies, respectively, the element And 3, the counter 4 pulses, the locking element 5, block 6 reset

The device works as follows.

The initial states of all counters are zero. Upon receipt of the input of the counters 1 and 2 pulses f and f (Fig. AC1, C) at their output will be

impulses with frequency --- and -..- (FIG. 3, g

to 14

And the pulses arrive at the first entrance to

fixing element 5 (counting input counter). Element 3 is the logical multiplication of pulses from counters 1 and 2. Pulses from the output of the element And 3 (Fig. Zd) arrive at the second input of the fixing element 5. (Input-reset of the counter). In this case, the pickup element 5 (of the counter) is in a retarded state. Since the frequencies f and fx differ from each other, the pulses that arrive at the inputs of the element And 3 change their position relative to each other, and at the output of the element And 3 there is a decrease in the pulse duration and after a certain time interval the pulses from the output of the element And 3 disappear (fig. Rear). If the time during which the pulses disappear is less than the time interval specified by the counters 1 and 4, then the pulses coming from counter 1 to the first input of the locking element 5 cause it to trigger, which indicates the frequency deviation f for a given tolerance.

This device allows monitoring the frequency deviation both downwards and downwards. This is due to the fact that the pulses disappear from the output of the element and 3, which are caused by the movement of the pulses from the outputs of the counters 1 and 2 relative to each other, are recorded. In FIG. 3 shows diagrams for the case when fg f, in FIG. 4 when f - f. If during the time interval specified by the counters 1 and 4, the pulses at the output of element 3 I did not disappear, the block b sets the counters 1, 2 and 4 to the zero state and the alarm is repeated again. In this case, the element 5 does not work, the frequency f is in the specified tolerance. As the locking element 5, a counter can be taken, the first input (counting input) of which receives pulses from counter 1, and the second input (counter reset input) from the output of the FROM element. The locking element 5 detects the disappearance of three pulses from the output of the element And 3. This is as follows. Counter 5 counts the pulses arriving at the counting input from counter 1, and simultaneously the reset input of counter 5 receives impulses from the output of element 3. As the frequency of the signals arriving at both inputs of the counter is close, the counter is in a decelerated state, t. e. It does not have time to count three impulses. If three pulses do not arrive at the reset input, a pulse appears at the output of the counter, indicating that the pulses from the output of element 3 have disappeared. Choosing the counter as the fixing element makes it possible to most easily detect the disappearance of three pulses.

The insertion of the element 3, the locking element 5, of the counter 4 makes it possible to reduce the volume of the device and increase its reliability.

Claims (2)

Invention Formula A device for frequency control, containing a reset unit whose output is connected to the inputs of pulse counters of the monitored and reference frequencies, characterized in that, in order to improve the reliability of the device, a pulse counter and serially connected element I and the locking element, the second input of which is connected to the output of the pulse counter of the reference frequency, to the input of the pulse counter and to the first input of the element I, the second input of which is connected to the output of the pulse counter of the monitored frequency, while the second input of the pulse counter is connected to the output of the reset unit, input which is connected to the output of the counter pulses. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 519643, cl. G 01 R 23/00, 01.23.75, 2. USSR author's certificate No. 531091, cl. G 01 R 23/00, 04/08/75. ... l .... P eleven iL. (igg and IIIIIIIIIIIIIIIIJilL. t P .-Jl