SU1599894A1 - Device for monitoring nominal speed of magnetic tape - Google Patents

Abstract

The invention relates to instrumentation and can be used in the equipment of accurate magnetic recording. The purpose of the invention is to simplify the device. The device contains a counter, a reference generator, the output of which is connected to the counter input, the first and second triggers, the input terminal, the first OR circuit connected by the first input to the output of the first trigger, the display unit, the first circuit I. A divider by 2, one-shot, The second AND circuit, EXCLUSIVE OR NOT circuit, is connected to the divider output 2 by the first input and 2 to the installation input of the counter and the second input of the first OR circuit to the output, the second trigger is connected to the output of the divider 2 and the output of the first trigger, and output - to the second input of the scheme EXCLUSIVE OR-NOT. 2 Il.

Description

 The invention relates to a magnetic recording technique, namely, devices for monitoring the speed of a magnetic tape in storage of information, and can be applied to devices for monitoring the frequency of rotation of electric motor shafts in the presence of tachometers.

The purpose of the invention is to simplify the device.

FIG. 1 shows a block diagram of a device for controlling the rated speed of a magnetic tape; in fig. 2 - time diagrams.

The device contains a counter 1, a reference generator 2, the first trigger 3, BJOpo and trigger 4, the input terminal 5, the first element 6 OR, the second element 7 OR, the display unit 8, the first element AND 9, the divider 10, one brator And the second element AND 12, the element EXCLUSIVE OR NOT 13, connected in a certain way.

The padoTaet device is based on the temporary selector principle.

At the input of the divider 10 from the clamp 5, a sequence of pulses is received, the frequency of which is proportional to the speed of movement of the magnetic tape (Fig. 2a). Divider 10 divides the frequency of the input signal by 2.

 From the output of the divider 10, pulses in the form of a meander (Fig. 26) arrive at the one-oscillator 11, which generates a short pulse when the front of the meander (Fig. 2c) arrives. Short pulses are fed to the second input of the OR element 7. From the reference generator 2, the pulses arrive at the counting input of counter 1. According to the installation input, the counter 1 is set using a signal from the output of the element 13 SENSOR OR NOT (Fig. 2d). At a high logic level of the signal, the splitter 10 at the output of trigger A is set to logical 1 (Fig. Ze).

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In this case, the installation input of the counter 1 receives a high logic level, prohibiting the account.

Suppose that at the rated speed of the magnetic tape, the period of the input signal is (n + m) T, where T is the duration of the period of the pulses of the reference generator; Pit is the number of pulses, and 2m T is the allowable range of variation of the period of the input signal.

The code of the number n is deciphered by the element 9 I, the code of the number 2m by the element I 12.

With the arrival of the pulse decay from the output of the divider 10, a negative front of the selector pulse (Fig. 2e) is formed at the output of trigger 3 and at the first input of the element OR 7.

Since the selector pulses from the output of the trigger 3 (Fig. 2d) and the selectable pulses from the output of the one-shot 11 (Fig. 2b) do not coincide in time, then at the output of the element OR 7 there will be no selectable pulses (Fig. 2g).

At the speed of the magnetic tape, the selector and selectable pulses at the inputs of the element OR 7 are present simultaneously, B as a result, selectable pulses appear at the input of the display unit 8 (Fig. 2g).

If the speed of the magnetic tape, the selector pulse will not form.

the pulses at the input of the display unit 8 will be absent.

Claims (1)

Invention Formula The control device of the nominal speed of the magnetic tape, containing a counter, a reference generator, the output of which is connected to the counter input, the first and second triggers, the input terminal, the first OR element, the output of which is connected to the first input of the first trigger, the second OR element connected by the first input to the output the first trigger, the display unit, the first element AND, characterized in that in order to simplify the device, a divider for two is entered into it, the input which is connected to the output terminal, a one-shot connected between the output of the divider 2 and the second input of the second element OR, the second element AND connected to the inputs with the corresponding outputs of the counter, and the output from one of the inputs of the first element OR, the element EXCLUSIVE OR-PE, connected by the first input to the output of the divider into two, and the output - to the installation input of the counter and the second input of the first element OR, while the second trigger is connected by inputs to the output of the divider into two and the output of the first trigger, and the output to the second input of the EXCLUSIVE OR element, the first AND element is connected between the outputs of the counter and the second input the first trigger, the output of the second element OR is connected to the display unit. and V / n giplgishl rt ii p P L E account PT “-E pgi rt ii p P Have i PT  J oh well rig. 2