SU1255937A1 - Device for monitoring pulse repetition frequency - Google Patents

Abstract

The invention may be used in frequency control systems, e.g., the angular velocity of rotation of the spindle of the magnetic disk drive. The purpose of the invention is to increase the reliability of the device. The device contains a one-shot 2 with a launch, element 4 and 5 pulse counter. The introduction of element 2I-OR 7, a pulse counter 8 and a pulse-generator 3 reduces the probability of generating false signals of a decrease in frequency in the presence of interference due to the increase in the signal of a decrease in frequency only after the M-fold confirmation of the fact of a deviation. 2 Il. Q S slud SP JV with CA “FIG.

Description

one

The invention relates to a pulse technique and is intended for use in frequency control systems, for example, the angular velocity of rotation of a spindle of a magnetic disk drive,

The purpose of the invention is to increase reliability by reducing the likelihood of generating false signals about frequency reduction in the presence of interference by issuing a signal about frequency reduction only after the M-fold confirmation of the fact of deviation.

FIG. 1 shows the functionality

device schematic; in fig. 2-15 com (Fig. 2 b). At the same time, the impulses, the time diagrams, by operation of the output of the one-vibrator 2 through the second

that device.

The device contains an input bus 1, - one-shot 2 with repeated

Starting, the generator of 3 pulses increases with the frequency of the input variable, element 4, the first counter 5 of the sequence of pulses (Fig. 2a), pulses, the output bus 6, element 2I-OR 7 and the second counter 8 of pulses.

the duration of their period becomes shorter than the duration of the pulses of the one-shot 2 with the restart of the one-shot 2, with the restart, (steady state). At the output of the generator 3 pulse time-one-oscillator 2 is set

Input bus 1 is connected by input

and the direct input of the AND 4 element, the output of which is connected to the counting input of the first pulse counter 5, the output of which is connected to the inverse input of the AND 4 j element by the output bus 6 and the direct input of the first AND element 2I-OR 7 and the inverse input The second element And element 2I-OR 7, the second direct input of the first element And element 2I-OR 7 is connected to the output of the second counter 8 pulses, the reset input of which is connected to the generator output 3 time pulses, and the counting input from the one-shot output 2 with a rotary start and the second inverse in house 2I second AND-OR element 7, whose output is connected to the reset input of the first counter 5 pulses.

The device works as follows.

In the initial state, at the outputs of pulse counters 5 and 8, the levels of logic O, the element AND 4 and the second element AND of the element II-OR 7 are open. I

The counter 5 impulses generates a logical 1 signal at its output after counting N pulses from an output of an element 4. The impulse counter 8 generates a logical 1 signal at its output after counting M pulses from the output of a single vibrator 2 with a restart. The generator 3 pulses of time forms at its output a pulse of logical 1 after arriving at its input (M + 1) -th pulse from the input bus 1.

If the frequency of the input sequence pulses is below a predetermined value and gradually increases (acceleration mode), their follow-up period (Fig. 2a) is longer than the duration of the pulses generated by the one-vibrator 2 with the restart element AND 2I-OR 7 (Fig. 2g) constant This resets the pulse counter 5 to the initial state. By

the level of logic 1 (Fig. 2S), the reset of the counter 5 pulses does not occur and it starts counting the input

pulses. After the arrival of an N-ro pulse on the output bus 6, a logic level 1 is set (Fig. 23), informing that the input signals have exceeded the frequency of a given value. This level closes the element AND 4 and the second element AND element 2И-OR 7, at the same time opening the first element AND element 2И-Ш1И 7.

In the established mode, the counter 8 pulses of each (M + 1) -th pulse of the input sequence through the generator 3 pulses of time (Fig. 26) is reset. In the case of a real reduction in the frequency of the input pulses (deceleration mode), the output of the single-vibrator 2 with the restarting again begins to form pulses (Fig. 2B), as the period of the input signals became longer (Fig. 2c () than the duration one-shot pulses 2. A counter of 8 pulses starts counting them and after counting

The m-th pulse of the logical 1 signal from the output of the counter of 8 pulses through element 2-OR 7 will reset the counter of 5 pulses to the initial state. Uro312

The logical logical O indicates that there is a real reduction in the frequency of the input pulse sequence (Fig. 28). If the formation of pulses at the output of the one-shot 2 with a restart is random and is not related to the appearance of pulses on the input bus 1 (for example, the one-shot 2 fails due to interference), then the generator 3 of the pulses after a time interval proportional to (M + 1 ) The th pulse from the input bus 1 will form a pulse that will reset the pulse counter 8 to its initial state (FIG. 2 g), since the probability of occurrence at the output of the one-oscillator 2 with restarting at this time interval M pulses is small.

By varying the coefficient M, it is possible to achieve a very low probability of producing a false signal about a reduction in the frequency of the input pulse train in the presence of faults in the one-shot 2 with restart from interferences,

Claims (1)

Invention Formula A device for controlling the frequency of a pulse train, containing an input and output bus, a single-vibrator with a restart, acceleration mode Vuc / to vffny / ttcoS M Jl-JUl-.J four And the first pulse counter, the output of which is connected to the output bus and the inverse input of the element I, the direct input of which is connected to the input bus and the input of the one-shot with restarting, and the output connected to the counting input of the first pulse counter, characterized in that In order to increase reliability by reducing the likelihood of false alarms about frequency reduction in the presence of interference, element 2I-1111, a second pulse counter and a time pulse generator, the output of which is connected to the reset input, are introduced into it. pulse counter, the output of which is connected to the first direct input of the first element AND element 2И-OR, the output of which is connected to the reset input of the first pulse counter, the output of which is connected to the second direct input of the second element And element 2И-OR and the first inverse input of the second element And element 2I-OR, the second inverse input of the second .element And which is connected to the counting input of the second pulse counter and the output of a one-shot with a restart, the input of which is connected to the input of the generator of time pulses. / (UpanoVi8 / IIS mode Mvft WMedMffUJt -LJlJlJul .... a  Uff / ryjttcof ff in VNIIPI Order 4816/44 Circulation 778 Subscription Pro-e. pr-tie, Uzhgorod, st. Project, 4