SU665320A1 - Apparatus for magnetic recording of information - Google Patents

Description

The invention relates to the field of instrumentation, namely to a device for magnetic recording of information, also for reproducing it.

A device for magnetic information recording is known, comprising a multi-speed tape mechanism and a number of identical channels, each of which uses a separate magnetic head connected to the amplifier. When changing the speed of the magnetic tape in such a device, it is difficult to precisely adjust the level of the reproduced signals, which distorts the output data.

Closest to the invention is a magnetic information recording device comprising a block for switching its operating modes and a number of identical channels, each of which includes a recording amplifier consisting of switching transistors, a playback amplifier connected to an automatic gain control circuit (AGC), the emitter follower connected to the recording amplifier and the matching transistor, as well as a magnetic head connected between the mentioned amplifiers with a winding 2. Typical for such a device edostatochno high noise immunity and

The accuracy of the reproducible signal level control is low.

The purpose of the invention is to increase the noise immunity of the device and the accuracy of the reproducible signal level control. This goal is achieved by the fact that a switch connected to switches of other channels and with all windings of magnetic heads of the same channels is inserted into the channel of the proposed device, while the switch of operating modes is connected to recording amplifiers and to free leads of switches. A transistor is inserted into each recording amplifier.

current, the collector of which is connected to the emitters of both switching transistors, an additional matching transistor, the collector of which is connected to the base of one of the switching transistors, and

fixing diode, the anode of which is connected to the collector of the additional matching transistor, and the cathode - to the base of the emitter follower.

The switch is made on three pairs of field-effect transistors, in two of which the sources are connected to the reproduction amplifier, the gates are interconnected, and the drains are connected to the corresponding electrodes of the third pair of transistors loaded on the windings of the magnetic heads.

The drawing shows a diagram of the proposed device.

The switch 1 of the operation modes of the resistor 2 and the matching transistor 3 is connected to the emitter follower 4 loaded on the resistor 5 and on the zener diodes 6 and 7, and through the switch 8 it is connected to the windings of 9 magnetic heads (not shown) and recording amplifiers 10. There can be several switches in the device.

Each switch is connected to a playback amplifier 11 connected to an AGC circuit 12. Each recording amplifier includes switching transistors 13 and I, a current transistor 15 loaded on a resistor 16, a fixing diode 17 and a matching transistor 18 loaded on a resistor 19. A similar purpose has a transistor 20, working in conjunction with the emitter follower and matching transistor 3. Each switch 8 consists of three pairs of transistors: the first pair includes transistors 21 and 22, the second - transistors 23 and 24 R to the third pair - transistors 25 and 26. These transistors can be mainly field.

In the information recording mode, the output signal of the switch 1 forms the input signal for the selected group or one recording amplifier. In this case, the transistor 3 opens, its collector current is amplified by the emitter follower and comes to the zener diodes. The stabilized voltage from the zener diode cathodes goes to the bases of transistors 15 and to transistors 14, respectively. In the absence of signals on the recording amplifiers, the base current of transistors 13 is zero, these transistors turn out to be closed and then the recording current flows through transistors 14 and 15 by magnetizing through the cores magnetic heads in one direction.

The transistor 18 opens when a positive voltage is applied, the voltage on the bases of the transistors 13 increases and it is detected by the diodes 17 at a level higher than the voltage on the bases of the transistors 14 by the amount of voltage drop on the open diode 17 and on the base-emitter junction of the transistor 4. In In this case, the transistor 14 is closed, and the transistor 13 is opened, providing current transfer to another part of the head winding. This causes a reversal of the core core in a different direction.

In the Stop and Playback modes, the voltage at the corresponding outputs of switch 1 is zero, and the voltage at the emitter follower output is equal to the supply voltage. In this case, the switching transistors of the amplifiers

records closed. When the positive voltage switches are fed to the inputs of the switches, transistors 21 and 22 are connected to the amplifiers, the other windings are shorted by the transistor 25. When the same voltage is applied to the other inputs of the switch, the shunt is the transistor 26, and in this case transistors 23 and 24.

10 The invention not only improves the quality of the recorded and reproducible information, but also simplifies the circuit by halving the number of recording amplifiers.

15

Claims (3)

1. A magnetic information recording device comprising a switch of its operation modes and a number of identical channels, each of which includes a recording amplifier consisting of switching transistors, a reproduction amplifier connected to an automatic gain control circuit connected to 5 an emitter follower and a matching transistor, as well as a magnetic head with a winding connected between these amplifiers, characterized in that, in order to increase the noise immunity of its operation and the accuracy of controlling the level of reproduced signals, a switch connected to the other switches is inserted into each channel channels and with all the windings of the magnetic heads of the same channels, while the mode switch is connected to the recording amplifiers and to the free pins of the switches. 2. The device according to claim 1, characterized by the fact that a current transistor is inserted into each recording amplifier, the collector of which is connected to the emitters of both switching transistors, an additional matching transistor whose collector 5 is connected to the base of one of the switching transistors, and a fixing diode, the anode of which is connected to the collector of the additional matching transistor, and the cathode to the base of the emitter follower. 0 3. A device according to claim 1, differing from the fact that the switch is made on three pairs of field-effect transistors, two of which have sources connected to a reproduction amplifier, the gates are interconnected, 5 and the drain is connected to the corresponding electrodes of the transistors of the third pair, loaded on the windings of the magnetic heads. Sources of information taken into account in the examination .1 USSR author's certificate No. 514330, cl. G 11 On 5/09, 1974. 2. USSR author's certificate No. 411498, cl. G 11 On 5/06, 1973.