SU1314380A1 - Device for controlling rotational speed of electric motor shaft in magnetic tape recorder - Google Patents

Abstract

The invention relates to instrumentation. The purpose of the invention is to expand the range of rotational speeds of the motor shaft by increasing the stability of the dynamic and static characteristics of the device. The device contains an electric motor 1, a rotation speed sensor 2, shapers 3 and 4 short pulses, a sawtooth voltage generator 5, a logarithmic amplifier 6, a differentiating amplifier 7, a key 8, a memory block 9, a summing amplifier 10, a power amplifier 11 and a bus 12, intended for supplying control voltage. The introduction of new elements and the formation of new connections between the elements of the device allows, by varying the voltage of the control signal supplied to the bus 12, smoothly and in a large range to regulate the rotation speed of the motor 1. 2 Il. (About with 4 CO 00. F

Description

The invention relates to instrumentation, in particular to a device, with which it is possible to regulate the speed of rotation of an electric motor shaft in a magnetic recording apparatus.

The purpose of the invention is to expand the range of rotational speeds of the motor shaft by increasing the stability of the dynamic and static characteristics of the device.

FIG. 1 shows a block diagram of the device; in fig. 2 - diagrams of signals at various points of the device.

Motor 1 is connected to a rotational speed sensor 2, which is connected to an electrical circuit consisting of a series of short pulses connected in series to one first generator, a second short generator to second driver 4, a generator 5 | 1., A 1 voltage, a log amplifier 7, a differential amplifier 7 , key 8, memory block 9, summing amplifier 10 and power amplifier 11 loaded (connected) to the electric motor 1. The output of the first formulator 15 of the switch 3 is connected to a separate input of the key 8, and the second input is summed go usi-, 1itel I) with bus 12, designed for a meter of control voltage supply.

In the process of rotation of the shaft (not shown) of the electric motor, the sensor 2 generates a periodic signal at output 13. This signal in the shaper 3 is converted into short pulses at its output 14, both at the input of the key 8 and at the time of the shaper 4, in which converting short pulses in such a way that output 15 produces the same pulses, but shifted 1U of time, i.e., the leading edge of the pulses at 1 output 15 coincides with the trailing edge of the TONi pulses received at the output 14. As a result, the effect is the samethe fronts of the pulses of both formers are on key 8 and on generator 5, which is triggered by pulses from the formation of 4 h.

At the output 16 of the generator 5, the discharge of the linearly increasing voltage occurs strictly synchronously with the arrival time of the leading edge of the impuser coming from 1 (the output of the 15 generator 4. In the amplifier 6, the signal is amplified according to the logrithmic law, as a result 17 generated; Prologized EIG

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cash, and the output 18 - differentiated signal received at a separate input key 8.

Thus, at various inputs of the key there is a rectangular pulse from output 14 of driver 3 and output 18 of differentiating amplifier 7. The leading edge of the pulse (Fig. 2) of the differentiated signal coincides with the falling edge of the pulse received from the driver 3. Therefore, the latter opens the key 8 and a differentiated signal with little or no distortion enters the memory block 9, in which it is stored until it is fed to the summing amplifier 10. The possibility of such a supply arises at the time of the signal voltage through the bus 12 ala control.

 In the summing amplifier, the addition of two signals occurs - a control signal and a differentiated (and previously pre-calibrated) signal from the sawtooth generator. A signal is then generated at the output of the coupler 10, allowing it to be amplified in a power amplifier according to a law close to linear. This means that by changing the voltage of the control signal applied to the bus 12, it is possible to regulate the speed of rotation of the motor shaft smoothly and in a sufficiently large range.

Claims (1)

Invention Formula An apparatus for controlling the rotational speed of a va.ch electric motor in a magnetic recording apparatus, comprising a rotational speed sensor associated with an electric motor, the output of which is connected to a series of short pulses and a sawtooth generator via a first short pulse shaper and a key to serially connected a memory unit that combines the WSI / strut and the power amplifier loaded on the electric motor, characterized in that, in order to extend the range At the speeds of rotation of the motor shaft due to the increased stability of the dynamic and static characteristics of the device, serially connected are introduced into it. artifact and differentiating amplifiers, the input of the first of which is connected to the output of the sawtooth generator, and the output of the second to the second input of the key. / j /four r / r one y v / PP /five P P Yes 77 fie, 2