RU1818635C - Method for magnetic recording of digital information - Google Patents

Abstract

The invention relates to instrumentation, in particular to a magnetic recording technique. The purpose of the invention is to increase the recording density. In the recording method, an interval of 2T is additionally formed when recording two information units following in a continuous binary sequence, while for the 2T interval, three recording pulses are generated, and in the 1.5T interval, a second pulse is generated after 0.8T from the beginning of this interval. 2 ill.

Description

The invention relates to instrumentation, in particular to a magnetic recording technique. and can be used in information recording systems and external storage devices of computer technology.

The purpose of the invention is to increase the recording density by increasing the information capacity of the recording (reproducing) signal and by reducing distortion of reproduced signals.

Fig. 1 is a timing chart of recording and reproducing signals by this method; figure 2 is a block diagram of a implementing device.

The signals of the initial information sequence are converted into an intermediate three-interval signal A with a mixed multiplicity of discrete time intervals (clock periods) of this signal, equal to 1T, 1.5T and 2T, where T is the duration of the clock period of the recording signal. Information O and 1 correspond to signals at intervals of 1T and 1.5T, respectively. Two information units (an even number) are converted into signals having intervals equal to 2T.

In the bit positions for informational O, single pulses are generated in the middle of this interval, i.e. 0.5T from the beginning of the 1T interval. Intervals 1.5T and 2T record time in pulses. In the bit positions for odd informational 1 (individual 1), the second and third pulses form after 0.9T and 1, ZT from the beginning of this interval (1.5T), and the first pulse of this interval is formed after 0.4T and 0, ZT from it start, if this interval follows after the intervals of 1.5 and 2T (1 T), respectively. In the bit positions of the two information 11 pulses are generated at 0.5T, 1, 3T and 1,7T from the beginning of the corresponding interval (2T). Pulse

00

with

B

ate

1T interval is set at 0.6T if this interval follows the 1.5T interval and before the 1T (2T) interval.

Recording onto the medium is carried out by rectangular pulses of alternating polarity, with saturation of the medium from + HF to -HF, while recording can be done according to the old signalogram (without preliminary erasing). . .

A device for implementing the proposed method (Fig. 2) comprises an input unit 1, a pulse sequence generating unit 2, an alternating polarity pulse shaper 3 and a magnetic head 4, connected in series

The device operates as follows.

The signals of the initial information sequence in the input block 1 are converted into a three-interval signal (Fig. 1A), from this signal in block 2, a pulse sequence B is formed, from which the pulse generator of the recording signal (Fig. 1 B) of alternating polarity is produced by the shaper 3 - a head 4 for recording onto a magnetic recording medium (not shown in the drawing).

The playback signal is three-interval with a multiplicity of intervals of 1: 1.5: 2 (Fig. 2G) - All information contained in the reproduction signal (Fig. 2D) is transferred by the intersection points (zero-transitions) of this signal with the axis of symmetry. This signal has a self-synchronization and a detection window of ± 0.25T. Decoding the signals of the original information sequence and extracting the clock signal is carried out from the generated reproduction signal (Fig. 1 E). Intervals 1T and 1.5T of the reproduced signal correspond to bit positions of information O and 1, and to interval 2T - two information 11.

Decoding is unambiguous. Decoding can be resumed at any information site. No accumulation of errors. .

The information capacity of the reproduced signal when recording the sequence 000 is 2 bits / period, of the sequence 1111 (even number 1) is 2 bits / period, and the sequence

0101 (O and D alternating) is 1.6 bits / period (worst case).

Changing the intervals (minimum) between the recording pulses from 0.251 to 0.4 T makes it possible to reduce the recording clock period from 1.5 to 1.0 (5 / V.

The technical and economic effect of the invention consists in increasing the recording density 1.2 x 1.5 1.8 times (80%), of which 1.5 times due to a change in the conditions for implementing the method (reducing the clock period from T 1.5 d / V to T d / V and 1.2 (by 20%) due to the increase in information capacity (in the worst case) compared with the prototype. As a base object selected miniKNML type EC-5091 with a maximum recording density of up to 100 bits / mm, the proposed method provides recording on a cassette tape with a frequency of 17 kHz, which corresponds to a density of 480 bits / mm, i.e. 4.8 times higher.

The greatest effect from the application of the proposed method is achieved using a universal magnetic head.

Claims (1)

The claims A method of magnetic recording of digital information, in which the recording signal is formed in the form of short rectangular pulses of alternating polarity with intervals of 1 T for information O, 1.5 T and 2 T for information G, where T 5 / V is the duration of the clock frequency of the recording signal, / d is the magnitude of the working gap of the magnetic head, V is the speed of the magnetic recording medium, and pulses are generated in the interval 1T through 0.5T from the beginning or through 0.6T if this interval follows after the interval 1.5T and before the interval 1T or 2T, in in the 1.5T interval, the first pulse is formed after 0.4T or O.ZT from the beginning, if this interval follows after the 1.5T and 1T or 2T intervals, respectively, and the third pulse through 1.3T from the beginning of this interval, and in the 2T interval, three pulses through 0.5T, 1, ZT and 1.7T, respectively, and the received signal is recorded on a magnetic medium, characterized in that, in order to increase the recording density, a second pulse in the range of 1.5T is formed after 0.8T from the beginning this interval.