SU605239A1 - Arrangement for rerecording information on magnetic tape - Google Patents

Description

one

The invention relates to the field of instrumentation, and. specifically for recording and reproducing equipment on a magnetic tape, and can be used in storage devices and data preparation devices on a magnetic tape.

There are known devices for rewriting information on a magnetic tape, which contain a single gap magnetic head, which is used for both recording and reading 1J.

However, the known devices are not reliable enough.

The closest to the invention to the technical essence is a device comprising a trigger connected by an output to the first input of the element AND, a playback amplifier, the output of which is connected to the trigger input, a pulse generator, the output of which is connected to the second input of the element 2.

When rewriting the information zone, the magnetic head first operates in the playback mode, when the first bit of the information zone located on the tape is detected, it switches to the recording mode and this information zone is overwritten.

A disadvantage of the known devices is that the period of the following clock recordings is not related to the moment of detection of the first bit of information. In this case, the maximum delay of the next sync pulse is equal to the period they follow.

2

Thus, when repeatedly rewriting an information zone, it is shifted in the forward direction by an amount proportional to the number of overwrites. Such a shift of information zones leads to a change in the interband gap and entails a malfunction of the device.

The purpose of the invention is to increase the reliability of rewriting information on a magnetic tape.

The goal is achieved by the insertion of a series-connected element NOT, a second trigger, a second coincidence circuit, a counter and an OR circuit, a second

the input of which is connected to the input of the circuit NOT connected with the output of the first coincidence circuit, wherein the inversion input of the second trigger is connected to the third input of the first coincidence circuit, and the second input of the second coincidence circuit is connected to the generator.

The device extracts the sync pulses from the moment of detection of the first bit of information from a sequence of high frequency pulses produced

pulse generator.

FIG. 1 shows a block diagram of the proposed device for rewriting information on a magnetic tape; in fig. 2 - diagram of the operation of the device overwriting information on

Claims (2)

magnetic tape. The device contains a booster amplifier 1, the signals from which are fed to the trigger 2, the output from which is fed to the first circuit AND 3. From the circuit AND the signal through the element 4 is fed to the second trigger 5, from which through the second circuit AND 6, the counter 7 and the OR 8 signal is transmitted from generator 9 to the output of the device. The rewriting device on the magnetic tape works as follows. When overwriting the information zone of the magnetape, the head first works in playback mode, at which time the pulse generator 9 continues to generate pulses, the frequency of which is several times higher than the frequency of the recording clock, which is determined by the information recording density on the magnetic tape. When the first bit of information approaches the magnetic head, the playback amplifier 1 generates a signal that turns on trigger 2. When trigger 2 is turned on and trigger 5 is turned off, the next pulse of pulse generator 9 passes through element 3 and enters the input of the OR element 8, which forms the first sync pulse ( Fig. 2). The magnetic head begins to work in the recording mode and records the first bit of the new zop information. The same impulse from the element 3 comes through the element 4 not to the pulse input of the trigger 5. On the trailing edge of this impulse, the trigger 5 turns on, which closes the element 3 and switches through the element 6 to the counter 7, which counts they are extracted from the pulse train to synchronize the recording, the frequency of which is determined by the given recording density. As shown in the diagram (Fig. 2), each third pulse of the generator 10 pulses is allocated. These pulses arrive at the element OR 8, which forms the sync pulses of the recording. When overwriting one zone to another with the same recording density, the offset of the first bit of the new overwritten information zone relative to the first bit of the previously recorded zone is inversely proportional to the ratio of the pulse generator frequency to the recording frequency (the tracking clock frequency) and is determined by the generator pulse tracking period. The use of the proposed device makes it possible to repeatedly rewrite information on a magnetic tape with high accuracy without significantly changing its location, which in turn greatly enhances the capabilities of these devices — reproduction on a magnetic tape. Claims A tape rewriting device comprising a playback amplifier, the output of which is connected to the trigger input associated with the output of a matching circuit, a pulse generator connected to the second input of the matching circuit, characterized in that, in order to improve the reliability of the rewriting, into it the series connected element is NOT, the second trigger, the second matching circuit, the counter and the OR circuit, the second input of which is connected to the input of the NOT circuit connected with the output of the first matching circuit, than the inverted input of the second flip-flop is coupled to a third input of the first coincidence circuit and a second input of the second coincidence circuit connected to the generator. Sources of information taken into account in the examination 1. US patent number 3360789, cl. 340-174.1, publ. 1967. 2. US Patent No. 3359548, cl. 340-174.1, publ. 1967. .G1  eight 171 full.f .. . I I I