JPH04157603A - Magnetic recording-reproducing apparatus for digital signal - Google Patents

Abstract

PURPOSE:To improve recording density by recording digital signals of a plurality of systems on the same track on a magnetic recording medium by a plurality of recording heads having different azimuth angles and by reproducing them by a plurality of reproducing heads having the same azimuth angles as the corresponding recording heads. CONSTITUTION:Digital signals of two systems subjected to multi-value amplitude phase modulation (multi-value APSK) are recorded on the same track on a magnetic recording medium 14 by two recording heads 12 and 13 having different azimuth angles respectively, and the recorded signals are reproduced by two reproducing heads 15 and 16 having the same azimuth angles as the recording heads 12 and 13 respectively. Since the signals of a plurality of systems are recorded on one track and the recorded signals are reproduced in this way, a magnetic recording-reproducing apparatus of digital signals which has a recording density improved to a large extent can be constructed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a digital video tape recorder (DV).
This invention relates to digital signal magnetic recording and reproducing devices such as TR).

BACKGROUND OF THE INVENTION In a conventional digital signal magnetic recording/reproducing device, two
Based on saturation recording of value signals, NRZI method and 8-1
Baseband recording modulation methods such as 0 conversion method 2 are often used (for example, "High-density magnetic recording technology used in digital VTRs", Shozo Nakayo, Journal of the Society of Television Engineers, Vol. 35, No. 7 (1981)) 542-548).

In addition, as another method, multi-value amplitude phase modulation (multi-value APS
There are magnetic recording and reproducing devices using carrier wave digital modulation methods, such as ``Study of High Efficiency Channel Coding in Digital VTRs'' by Toyohiko Matsuda et al.
1988 Institute of Electronics, Information and Communication Engineers Spring National Conference Lecture Collection Collection C-2, (1988) pp. 2-59).

Problems to be Solved by the Invention However, in the configuration using the baseband recording modulation method, only one system of signals can be recorded on one track. Further, even in the configuration using the above-mentioned carrier wave digital modulation method, only one system of signals is recorded on one track has been considered.

The present invention solves the above-mentioned problems, and aims to provide a digital signal magnetic recording and reproducing device that can record multiple systems of signals on one track, thereby greatly improving recording density. .

Means for Solving the Problems In order to achieve the above object, the present invention includes a plurality of carrier wave modulation means that respectively modulate carrier waves with input digital signals of a plurality of systems and generate modulation signals of a plurality of systems; The apparatus is equipped with magnetic recording/reproducing means for recording modulated signals on the same track on a magnetic recording medium using a plurality of recording heads each having a different azimuth angle.

Further, the magnetic recording/reproducing means reproduces and outputs a plurality of systems of reproduction signals by a plurality of reproduction heads each having the same azimuth angle as the plurality of recording heads; The system is equipped with a plurality of carrier wave modulation and demodulation means for demodulating the reproduced digital signal of the system.

Furthermore, when inputting the plurality of modulation signals to recording heads having different azimuth angles, the input signal level to the head recording later on the same track is set to be lower than the input signal level to the preceding head. It is equipped with a plurality of set recording amplifiers.

The apparatus also includes a bias circuit that adds a bias signal to the plurality of systems of modulation signals, and is arranged to input the output of the bias circuit to the magnetic recording and reproducing means.

According to the above-described configuration, the present invention records multiple systems of carrier-modulated digital signals on the same track on a magnetic recording medium using recording heads each having a different azimuth angle, and reproduces the recorded signals, thereby increasing the recording density. It is possible to construct a digital signal magnetic recording reciprocating device which is greatly improved. Since carrier wave modulated signals are recorded, signal components are concentrated near the carrier wave frequency, and the effect of azimuth loss can be utilized.

Furthermore, by adding a bias signal to the modulation signal, the influence of nonlinear distortion is alleviated, allowing recording and reproduction with a low error rate.

Embodiment Hereinafter, a digital signal recording/reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a bronch diagram showing the main part configuration of a digital magnetic recording/reproducing apparatus according to an embodiment of the present invention. In this embodiment, analog signals such as television signals and audio signals are input to the input terminal 1. The input analog signal is converted into a digital signal by an analog/digital converter (hereinafter abbreviated as A/D converter) 2. This digital signal is divided into two systems, and the first encoding means 3
and is input to the second encoding means 4.

The digital signal input to the first encoding means 3 is a two-digit multivalued digital signal (each digit is one signal, and Q signal). The multivalued digital signal output from the first encoding means 3 is input to the first multivalued APSK modulation means 5, where it is multivalued APSK modulated and output. The digital signal input to the second encoding means 4 is similarly converted into a two-digit multi-value digital signal corresponding to the multi-value APSK signal. The multivalued digital signal outputted from the second encoding means 4 is input to the second multivalued (iAPSK) modulating means 6, where it is multivalued (IAPSK modulated) and output.

For example, if the number of bits of the digital signal that is the output of the A/D converter 2 is 8, this digital signal is converted into a multi-value APS.
16-value orthogonal amplitude modulation (hereinafter referred to as l 6
Consider the case of recording using QAM (abbreviated as QAM). At this time, the first encoding means 3 and the second encoding means 4 can be configured as shown in FIG. 2, for example.

In FIG. 2, the 8-pin digital signal output from the A/D converter 2 is divided into two systems of 4 bits each and inputted to a first encoding means 3 and a second encoding means 4, respectively. The 4-bit digital signal input to the first encoding means 3 is divided into two systems of 2 bits each.
The binary/4 (i!) signal is input to the conversion means 101 and 102 and converted into a four-value digital signal. Similarly, the 4-bit digital signal input to the 20th encoding means 4 is converted into a 2-bit signal at a time. The signals are divided into two systems and input to binary/four-value conversion means 103 and 104, respectively, and converted into four-value digital signals.The two systems of multi-value digital signals output from the first encoding means 3 are as follows: 1st
The signal is inputted to the multilevel APSK modulation means 5, subjected to 16 QAM modulation, and outputted.

Similarly, the two systems of multilevel digital signals output from the second encoding means 4 are input to the second multilevel (IAPsK) modulation means 6, where they are 16QAM modulated and output.

Returning to FIG. 1, the two systems of multi-value APSK signals output from the first multi-value APSK modulation means 5 and the second multi-value APSK modulation means 6 are input to Calo calculators 8 and 9, respectively. It is added to the bias signal output from the bias generating means 7. The outputs of the adders 8 and 9 are input as recording signals to the first recording amplifier 10 and the second recording amplifier 1), respectively, and the recording heads 12 and 13, which have different azimuth angles, record the same image on the magnetic recording medium 14. recorded on the track.

An example of the positional relationship between the recording heads 12 and 13 at this time is shown in FIG. The first recording head 12 and the second recording head 13 have different azimuth angles. After the first recording head 12 records a signal on the recording track 30 on the magnetic recording medium 14, the second recording head 13 records the signal on the same recording trunk 30. At this time, the amplification factor of the second recording amplifier 1) is set smaller than the amplification factor of the first recording amplifier 10, and the signal level input to the second recording head 13 is lower than the signal level input to the first recording head 12. the signal level to be lowered. With this setting, the first recording node 12 transfers the multi-level APSK modulated signal to the magnetic recording medium 1.
After recording up to the deep part of 4, the second recording head 13
A multi-level APSK modulated signal of another system is recorded in a shallow layer portion of a magnetic recording medium. At this time, the signal recorded by the first recording nod 12 remains in the deep part of the magnetic recording medium.

Returning to FIG. 1, the signal recorded by the first recording nozzle 12 is transferred to the first reproducing head 15 (shared with the first recording head 12) which has the same azimuth angle as the first recording nozzle 12. (can also be played). Further, the signal recorded by the second recording head 13 is transferred to the second reproducing head 16 which has the same azimuth angle as the second recording head 13.
(The second recording can also be shared with the gutter 13). At this time, for example, the first playback
The azimuth angle of the first recording head 12 and the reproduction head 15, and the second recording head t are adjusted so that the amount of reproduction of the signal recorded by the second recording head 13 is reduced due to so-called azimuth loss. '13 and the azimuth angle of the second playback head 16.

The multivalued APSK signal reproduced by the first reproduction head 15 is equalized by the first equalization means 17 and then demodulated by the first multivalued APSK demodulation means 19. Similarly, the signal reproduced by the second reproducing head 16 is equalized by the second equalizing means 18, and then the signal is equalized by the second multi-level AP.
It is demodulated by the SK demodulation means 20. First multivalued APS
K demodulation means 19 and second multi-level APSK demodulation means 20
The output signals of are input to the first decoding means 21 and the second decoding means 22, respectively.

The first decoding means 21 and the second decoding means 22 can be configured as shown in FIG. 3, for example. In FIG. 3, the reproduced I signal and the reproduced Q signal from the first multilevel APSK demodulation means 19 are transmitted to the four-value/binary conversion means 201 and 20, respectively.
2, the reproduced 1 signal and the reproduced Q signal from the second multilevel APSK demodulation means 20 are converted into a 2(i! digital signal) by the 4-value/binary conversion means 203.
and 204, the signal is converted into a binary digital signal. The 4-bit binary digital signal output from the first decoding means 21 and the 4-pin binary digital signal output from the second decoding means 22 are combined as an 8-bit reproduced digital signal. The signal is input to an analog converter (hereinafter abbreviated as D/A converter) 23.

Finally, returning to FIG. 1, the reproduced signal converted by the D/A converter 23 is output to the output terminal 24 as a reproduced analog signal.
is output from.

As described above, according to the digital signal recording and reproducing apparatus of the embodiment of the present invention, two systems of multi-level APSK modulated digital signals are recorded on the same track on a magnetic recording medium by two recording heads each having a different azimuth angle. By recording and reproducing the recorded signals using two reproducing heads each having the same azimuth angle as the recording head, a digital signal magnetic recording/reproducing device with significantly improved recording density can be constructed. At this time, since a multilevel amplitude phase modulated signal is recorded, the signal components are concentrated in the vicinity of the carrier wave frequency, and the effect of azimuth loss can be utilized. Furthermore, by adding a bias signal to the modulation signal, the influence of nonlinear distortion is alleviated, allowing recording and reproduction with a low error rate.

In the above embodiment, the number of focuses of the digital signal that is the output of the A/D converter 2 is set to 8, and the case is described in which this digital signal is recorded using 16QAM, which is one of the multilevel APSK methods. However, the number of focuses of the digital signal and the number of multi-values of the multi-value APSK system can be arbitrarily selected. Moreover, when distributing the modulated signal, although it is distributed into two systems, the number of systems can be set arbitrarily.

Furthermore, in the above embodiment, a case was described in which multilevel orthogonal amplitude modulation was used, but amplitude phase modulation (APSK
), phase modulation (PSK), frequency modulation (FSK), and other modulation methods can also achieve similar effects.

Effects of the Invention As is clear from the above embodiments, according to the present invention, a plurality of carrier-modulated digital signals are recorded on the same trunk on a magnetic recording medium by a plurality of recording heads each having a different azimuth angle. By reproducing recorded signals using a plurality of reproducing heads each having the same azimuth angle as the recording head, a digital signal magnetic recording/reproducing device with significantly improved recording density can be constructed. At this time, since a carrier-modulated signal is recorded, signal components are concentrated near the carrier frequency, and the effect of azimuth loss can be utilized.

Further, by adding a bias signal to the modulation signal, the influence of nonlinear distortion can be alleviated, and a digital signal magnetic recording and reproducing device with a small error rate can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a digital signal magnetic recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the configuration of the first encoding means and second encoding means, and FIG.
The figure is a block diagram showing an example of the configuration of the first decoding means and the second decoding means, and FIG. 4 is a positional relationship diagram of the first recording throat and the second recording throat. DESCRIPTION OF SYMBOLS 1...Input terminal, 2...A/D converter, 3...First encoding means, 4...Second encoding means , 5...first multi-value APSK modulation means, 6...second multi-value APSK modulation means,
7...Bias generating means, 8.9...
Adder, 10...First recording amplifier, 1)...
. . . second recording amplifier, 12 . . . first recording head, 13 . . . second recording head, 14.
...Magnetic recording medium, 15...First reproducing head, 16...Second reproducing head, 17...
...First equalization means, 18...Second equalization means, 19 Old...First multi-level APSK demodulation means, 20
...Second multi-level APSK demodulation means, 21...
...first decoding means, 22...second decoding means, 23...D/A converter, 24.old...output terminal, 30... record track. Name of agent: Patent attorney Haruaki Ogata (2 persons) Figure 2 Figure 3 Figure 4

Claims (7)

[Claims] (1) A plurality of carrier wave modulation means each modulating a carrier wave with a plurality of systems of input digital signals to generate a plurality of systems of modulation signals, and a plurality of recording heads each having a different azimuth angle to generate the plurality of systems of modulation signals. A digital signal magnetic recording and reproducing device comprising a magnetic recording and reproducing means for recording on the same track on a magnetic recording medium. (2) As a carrier wave modulation means, a plurality of encoding means each converting the input digital signals of the plurality of systems into multi-value digital signals, and a plurality of systems of multi-value digital signals that are outputs of the plurality of encoding means. 2. The digital signal magnetic recording and reproducing apparatus according to claim 1, further comprising a plurality of multi-value amplitude and phase modulation means for performing multi-value amplitude phase modulation on each of the signals and generating a plurality of systems of modulation signals. (3) the magnetic recording/reproducing means for reproducing and outputting a plurality of systems of reproduction signals by a plurality of recording heads and a plurality of reproduction heads each having the same azimuth angle; 3. The digital signal magnetic recording and reproducing apparatus according to claim 1, further comprising a plurality of carrier wave modulation and demodulation means for demodulating the reproduced digital signals of the system. (4) As a plurality of carrier wave modulation demodulation means, a plurality of multilevel amplitude phase modulation demodulation means demodulates the plurality of systems of reproduced signals into reproduced multilevel digital signals, respectively; 4. The digital signal magnetic recording and reproducing apparatus according to claim 3, further comprising decoding means for converting into a plurality of systems of reproduced digital signals. (5) When inputting multiple systems of modulation signals to recording heads with different azimuth angles, set the input signal level to the head recording later on the same track to be lower than the input signal level to the preceding head. A digital signal magnetic recording and reproducing apparatus according to claim 1 or 2, comprising a plurality of recording amplifiers. (6) Claim (1) or (2) further comprising bias means for adding a bias signal to a plurality of systems of modulation signals, and inputting the modulation signal to which the bias signals have been added to the magnetic recording/reproducing means. The digital signal magnetic recording and reproducing device described above. (7) The digital signal magnetic recording device according to claim 6, wherein the bias means adds a bias signal that minimizes nonlinear distortion of the reproduced signal from the magnetic recording medium to the plurality of modulation signals. playback device.