JPH06243411A - Magnetic recording method for plural number of channels - Google Patents

Abstract

PURPOSE:To suppress noises by shifting polarity changing points of digital signals in plural number of channels. CONSTITUTION:Digital signals in at least a portion of the channels of plural number of channels are delayed for a minute and prescribed amount of time by delay circuits 22 to 2n. Thus, the polarity changing points of digital signals in plural number of channels are mutually shifted and the digital signals in these plural number of channels are simultaneously recorded on a magnetic recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-channel magnetic recording method for simultaneously recording multi-channel digital signals on a magnetic recording medium.

[0002]

2. Description of the Related Art A magnetic recording apparatus used in transportation and aeronautical systems simultaneously records digital signals of a plurality of channels such as 4 to 16 channels on a magnetic recording medium composed of a magnetic card by a magnetic head of a plurality of channels. There is. In this magnetic recording device, when recording digital signals of a plurality of channels on a magnetic card, a magnetic head in which a recording head and a reproducing head are arranged side by side is used, and the digital signal is recorded on the magnetic card by the recording head. After that, the digital signal is immediately read from the magnetic card by the reproducing head, the reproducing system reproduces the digital signal from the read signal, and the digital signal and the digital signal are used to confirm (verify) the recorded data. The light method is generally adopted.

[0003]

In the above magnetic recording apparatus, since the digital signals of a plurality of channels are simultaneously recorded on the magnetic card by the recording heads of a plurality of channels, an inflection point of the recording current flowing in each recording head occurs at the same time. Feedthrough occurs due to a large change in the total sum of the recording currents flowing in each recording head. This feedthrough is that the magnetic flux generated by the recording head goes around to the reproducing head, and the feedthrough causes noise in the reproduced signal. Due to this noise, correct Baifai cannot be performed, which causes a reproduction error. The noise due to feedthrough is due to the coercive force of the magnetic card of 300,650,2.
The higher the value is, such as 750 oersted, the larger the value becomes, and it occurs even when the coercive force of the magnetic card is low. Further, the noise due to the feedthrough may have an influence on other than verification. Further, since the digital signals of a plurality of channels are simultaneously recorded on the magnetic card, the inflection points of the digital signals of a plurality of channels are generated at the same time, so that the electrical noise on the circuit increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-channel magnetic recording method which is capable of improving the above-mentioned drawbacks and suppressing noise by shifting inflection points of digital signals of multiple channels.

[0005]

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized by delaying the digital signals of at least some of the digital signals of a plurality of channels by a predetermined minute time. After shifting the inflection points of the digital signals from each other, the digital signals of the plurality of channels are simultaneously recorded on the magnetic recording medium.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a magnetic recording apparatus used in an embodiment of the present invention, and FIG. 2 shows its timing chart.
In this example, a plurality of (n) -channel digital signals DAT to be simultaneously recorded on a magnetic recording medium composed of a magnetic card.
A1, DATA2, DATA3, ... DATAn are divided into a plurality of groups, for example, four groups, and the first group of digital signals DATA1, DATA5, DATA.
9 are directly input to the recording circuits 11, 15, 19 ... As recording signals S1, S5, S9. Second group of digital signals DATA2, DATA6, D
ATA10 ... Are delay circuits 22, 26, 30 respectively.
.., the inflection point is deviated from the digital signals of the other groups by being delayed by a minute time, for example, 20 .mu.s, and input to the recording circuits 12, 16, 20 ... As recording signals S2, S6, S10. To be done.

The third group of digital signals DAT
A3, DATA7, DATA11 ... Are delayed by the delay circuits 23, 27, 31 ... S3
Recording circuits 13, 17, 21 ... as S7, S11 ...
..Inputted to the fourth group of digital signals DATA
4, DATA8, DATA12 ... Are each a minute time, for example, 6 due to the delay circuits 24, 28, 32 ...
Due to the delay of 0 μs, the inflection point is displaced from the digital signals of the other groups, and the recording signals S4, S
8, S12 ... As recording circuits 14, 18, 22 ...
・ Entered in. Here, the time lag due to the delay circuits 22, 23, 24 ... 2n of the digital signals of each group is set to a time that does not affect the reproduction signal of the reproduction system, for example, a minute time of about 10 to 20 μs. .

Therefore, the n-channel digital signals input to the recording circuits 11 to 1n have different inflection points for each group. If there are a large number of n channels, such as 16 channels, delaying the digital signals of the n channels by the delay circuits 22 to 2n so that the inflection point shifts for each channel, the digital signals of the n channels are However, if the n-channel digital signal is divided into four groups and shifted for each group, the reproduced signal will not be affected. The n-channel digital signals may be divided into two groups, and a delay circuit may delay the digital signals of at least some of the channels to shift the inflection point for each group.

The maximum time lag between the digital signals of n channels is no problem as long as it is within a few percent of the bit interval of the digital signals when the phase difference of each channel becomes a problem in the NRZ recording system or the like. The maximum offset time between digital signals on a channel depends on the recording density. When recording an n-channel digital signal on an ordinary magnetic card, there was no problem when the maximum shift time between the n-channel digital signals was set to 50 to 60 μs. When serial data is recorded on the magnetic recording medium in each channel, the size of the delay time of the delay circuits 22 to 2n does not matter at all.

As the n-channel magnetic head, one in which recording heads 31 to 3n and reproducing heads are arranged for each channel is used, and the recording circuit 11 is of a read-after-write type.
Digital signals S1 to Sn input to 1n are recorded on the magnetic card. That is, the recording circuits 11 to 1n receive the input n-channel digital signals S1 to Sn, respectively.
Is modulated by, for example, the FM system, and a recording current is supplied to the n-channel recording heads 31 to 3n according to the modulated signal.

The recording heads 31 to 3n record an n-channel digital signal on a magnetic card when a recording current flows, and immediately after that, an n-channel reproducing head is recorded from the magnetic recording medium by the recording heads 31 to 3n. Read digital signals of multiple channels respectively. A reproducing system including a reproducing head demodulates a read signal from an n-channel reproducing head to reproduce a digital signal and compares the digital signal with the digital signals S1 to Sn input to the recording circuits 11 to 1n. The quality of recorded data is verified.

In this example, digital signals DATA2-D
Since ATAn is delayed by the delay circuits 22 to 2n to shift the inflection point of the n-channel digital signals DATA1 to DATAn, it is possible to suppress the change in the total sum of the recording currents flowing in the recording heads 31 to 3n to be small. Through does not occur. For this reason, noise due to feedthrough is suppressed, correct baifing is performed, and a reproduction error is eliminated. Moreover, by shifting the inflection points of the n-channel digital signals DATA1 to DATAn, it is possible to suppress the change in the total sum thereof to be small and to suppress the electrical noise on the circuit.

[0013]

As described above, according to the first aspect of the invention, the inflection points of the digital signals of the plurality of channels are delayed by delaying the digital signals of at least some channels of the digital signals of the plurality of channels by a predetermined minute time. Since the digital signals of a plurality of channels are simultaneously recorded on the magnetic recording medium after they are shifted from each other, noise can be suppressed and a reproduction error or the like can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a magnetic recording device used in an embodiment of the present invention.

FIG. 2 is a timing chart of the same embodiment.

[Explanation of symbols]

 11-1n recording circuit 22-2n delay circuit 31-3n recording head

Claims (1)

[Claims] 1. The digital signals of a plurality of channels are magnetized after the inflection points of the digital signals of a plurality of channels are shifted from each other by delaying the digital signals of at least some of the digital signals of the plurality of channels by a predetermined minute time. A multi-channel magnetic recording method characterized by simultaneously recording on a recording medium.