JPS58179915A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To increase greatly the recording density of a data recorder/reproducer, by using a staircase wave generating circuit to convert a digital data into a staircase wave having a modulated period and then to record it to a recording medium. CONSTITUTION:The staircase waves of different periods in accordance with 1 or 0 of the signal at a terminal Q which is obtained by latching a data signal (a) by a latching circuit 11. In other words, the half period T of the staircase wave is short and long when the data (a) is set at 0 and 1 respectively. Then the staircase wave is recorded on a magnetic tape 3 by a tape recorder 7. In the reproduction mode, an output signal (c) is supplied to a buffer 14 of a comparator 5. At the same time, the top or bottom point of the signal (c) is held by the values of a diode and a capacitor. Then the amplitude center potential of the signal emerges at a capacitor C4 through a resistance. An operational amplifier 15 compares the signal with its amplitude center to extract a square wave (d) which has a short period to a signal 0 and a long period to a signal 1 respectively. Thus, the recording density is greatly increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium that stores digital data in a special format.

As is well known, the phase modulation method is mainly used to record digital data on magnetic tape.
Its recording density is 32 pits)/ll1m.

or 64 pits)/nu++ is the current situation.

The main object of this invention is to significantly increase such recording density.

That is, the present invention aims to provide a recording medium in which a signal obtained by converting input digital data a into a periodically modulated staircase wave as shown in FIG. 3(a) by a staircase wave generating circuit 1 is recorded. It is.

The signal obtained by reading out the data signal modulated into such a staircase wave has a waveform close to a periodically varied sine wave as shown in FIG.
A staircase wave with very small amplitude fluctuations must be determined so that it is easy to find the amplitude center to obtain the square wave shown in Figure (c).

Therefore, the staircase wave shown in FIG. 3(a) ideally has a shape that approximates a sine wave, and it is also desirable to advance the point in time at which the period is changed, taking into account the phase delay. Even if a staircase wave is recorded, it becomes smooth like the sine wave in (b) because it is operated at a frequency close to the continuous frequency of a recording device such as a tape recorder.

Next, as shown in FIG. 1, to specifically describe an example of the apparatus of the present invention, 1 is a staircase wave generation circuit for obtaining the staircase wave as described above, 2 is an amplifier, 3 is a magnetic tape, and 4 is the same. 5 is a comparison circuit that compares the read signals at the center of their amplitude; 6 is a period reading and decoding circuit; and 7 is a tape recorder. Further, a is a data signal to be recorded, b is a staircase wave shown in FIG. 3(a), C is a reproduced wave shown in FIG. 3(b), and d is a square wave similarly shown in FIG. 3(c). e indicates read data.

The staircase wave generation circuit 1 has an input terminal CI for the clock pulse ep.
and reset terminal R and output terminal TI, T2...
・Shift register 8 equipped with T6 (shift direction is from T1 to T6) and switching input terminals 01, 02, 03
and data input terminal UO.

A data selector 9 equipped with Ul, C2...C7 and an output terminal OUT, an input terminal IN from the output terminal OUT of this data selector 9, and output terminals Vl, V2.
．． A counter 10 having a voltage V3, a data latch circuit 11 that latches the value of a terminal W at the rising edge of a signal applied to a terminal X, and an AND circuit with a negative input connected to the output terminals Vl and V2 of the counter 10 an exclusive OR circuit EORI connected to the output terminal V2゜3 of the counter 10;
An exclusive OR circuit FOR2 connected to output terminals Vl and V3 of the counter 10, and each exclusive OR circuit EORI.

Each output of FOR2 is connected to a diode DI, D2...
It is comprised of a clamp circuit 12 that clamps by the forward potential difference of D4, and a digital-to-analog converter 13 configured by selecting resistors R4 and R5 at a ratio of 1:2.

In the data selector 9, when the input terminal 01 is O, one of the data input terminals UO to U3 is connected to the output terminal OUT according to the values of the terminals Vl and V2 of the counter 10, and when the input terminal 01 is 1, the output terminal OUT is connected. Similarly, counter 1
Data input terminal U according to the values of terminals Vl and V2 of 0
Any one of 4 to U7 is connected to the output terminal OUT.

Comparator 5, which compares at the center of amplitude, includes a buffer amplifier 14 and a diode D5. D6. D7. D8, resistance R7, R8
, R9, capacitors C2, C3, C4 and operational amplifier 1
5, which inputs signal C and outputs signal d.

The operation of such a staircase wave generating circuit will be described with reference to the waveform diagram in FIG. 2.

First, the output terminals Vl, V2 . Assume that the signal of V3 is (1, 0, 0). When the signal at the output terminal Q of the data latch 11 is O, the data selector 9
A signal from the data input terminal U1 is outputted to the output terminal OUT of the data input terminal U1. Also, since this data input terminal U1 is connected to the output terminal T3 of the shift register 8, when the clock pulse CP is input to the terminal c4 three times, a signal is output from the output terminal OUT of the data selector 9, and the resistor R1 and a capacitor C] to the reset terminal R of the shift register 8. At this time, the shift register 8 is reset and all outputs disappear. In this way, a signal narrower in width than the clock pulse CP can be extracted from the output terminal OUT of the data selector 9. When the signal at the output terminal OUT of the data selector 9 disappears, the output terminals Vl, V2 . The signal of V3 is (0, 1,
0).

In this case, the output terminal OUT of the data selector 9 will be connected to the data input terminal U2, and the output terminal of the data selector 9 will be connected to the data input terminal U2 at intervals of time determined by the connection between the shift register 8 and the data selector 9. Terminal OUT
A signal is taken from which advances the counter 10.

Output terminal Vl of counter 10 in staircase wave generation circuit 1
, V2 represent four steps of a staircase wave, and therefore, each time a signal is input from the input terminal IN, the level of the output signal S of this circuit 1 changes in a stepwise manner. Here V
l, V2. Each signal of V3 is V1=1. V2=1. V3=
x (x=0 or 1) and V1=0. V2=O,V
In the case of 3=x, the value of the output signal S is the same, and only in this case it stays at the same stage. That is, when a signal is input eight times from the input terminal IN of the counter 10,
A staircase wave for one cycle is obtained from the output terminal of the digital-to-analog converter 13, that is, the output terminal of the signal.

As shown in FIG. 3, the staircase wave has a waveform in which the amplitude sequentially increases from the reference value to the maximum value and decreases from the maximum value to the reference value.

The shift register 8 plays the role of a timer and serves as a time reference for each stage of the staircase wave, and the data selector 9 uses the data input terminals UO, Ul...U7 and the output terminal TI of the shift register 8 according to each stage. , T2...T6
It connects between.

Therefore, depending on the signal applied to the Cρ terminal, the data input terminals UO, 01...U3 or U4...U
Since the combinations of 7 can be switched, a staircase wave with a different period can be selected depending on whether the signal power of the terminal Q or O, which is latched by the latch circuit 11, is the signal power of the data a. That is,
In this embodiment, when data a is 0, the half period T of the staircase wave is short, and when a is 1, T is long. This staircase wave is recorded on the magnetic tape 3 by the tape recorder 7 via the amplifier 2.

Next, when reproducing the magnetic tape 3, the signal C read out via the amplifier 4 is input to the amplifier amplifier 14 in the comparator 8 and amplified, and the peak of the signal is reached by the diode D5 and capacitor C2. The peak of the signal valley is held by diode D6 and capacitor C8.

Therefore, the potential at the center of the amplitude of the signal is applied to the capacitor C4 through the resistors R8 and R9, and the operational amplifier 15 compares the signal and the center of its amplitude. For signal 1, a short square wave d with a long period is extracted.

Also diode D? , D8 are inserted to prevent the output of the operational amplifier 15 from being saturated.

<Example> 1/6MH from the clock pulse generator cp shown in Fig. 1
Input the z signal to the tape recorder 7 to set the tape speed to 48.
When cm/second is used, by recording one bit of data in a half period of the staircase wave, the half period is 66 μs for data “0” and 90 μs for data “1”. It's now seconds. Therefore, even when the recording density is low, as described above, the recording medium of the present invention can provide a recording density three times or more higher than that of the conventional recording medium.

Furthermore, according to the present invention, it is possible to determine whether the wave is ``1,000'' or ``1'' by the length between the zero-crossing points (points that intersect with the reference line) of the reproduced wave, thereby eliminating the influence of the tape recorder's wah, 7, etc. Good data recording and playback can be performed without any interference.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the present invention, Fig. 2 is a signal waveform diagram of the main part thereof, and Fig. 3 (a), (b) (e
) is the output signal waveform of the main part in FIG. 1... Staircase wave generation circuit, 2, 4... Amplifier, 3...
・Magnetic tape, 5... Comparator that compares at the center of amplitude, 6
... Periodic reading and decoding circuit, 7... Tape recorder. Patent Applicant: Kinki Keikokuki Co., Ltd. Agent: Patent Attorneys: Seihaku and Sogai (2 persons) Figure 2 Figure 3 (a) (b) (C)

Claims (1)

[Claims] (1) A binary level signal has a different period corresponding to each signal level, and within each period, the amplitude increases stepwise from the reference value to the maximum value, and from the maximum value to the reference value. 1. A recording medium, characterized in that a staircase wave having at least 1/2 cycle that decreases as an input signal is recorded.