JP3044823B2 - Magnetic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape recorder for recording digital data.

[0002]

2. Description of the Related Art Conventionally, a device for recording an analog signal is dedicated to analog as represented by a cassette tape recorder, and a device for recording data is dedicated to data recording as represented by a floppy disk or hard disk. .

Here, in a digital data recording device,
Using a magnetic head for recording / reproducing and a magnetic material with a coercive force and structure to obtain an appropriate recording density, the polarity of the current flowing through the magnetic head is switched to positive or negative to change the current on the magnetic material. It has a structure for recording as a change in magnetization. In such a magnetic recording apparatus, the current flowing through the magnetic head is set to a current value at which the magnetic material is sufficiently magnetically saturated, and the change point of the current is reliably recorded on the magnetic material. Also, new data is surely recorded, including erasure of data of a specific pattern recorded in advance.

On the other hand, in analog recording such as voice, when only a signal to be recorded is applied to a recording head, the magnetic material on the tape is not magnetized as a signal due to the hysteresis characteristic, and a large distortion occurs. Therefore, when recording an analog signal such as audio, a high frequency A
An AC bias method in which a C signal is also applied and a DC bias method in which a constant DC component is applied in advance are generally used.

Hereinafter, a tape recorder used for analog recording among the conventional recording apparatuses as described above will be described with reference to the drawings.

FIG. 6 shows the configuration of a recording / reproducing section of an analog recording tape recorder having an erasing head. In the figure, 1 is a recording / reproducing head, 2 is a recording / reproducing circuit, 3 is an erasing head, 4 is an erasing circuit, and 5 is a magnetic tape. At the time of recording, when the tape is run at a constant speed under the two heads while applying an erasing current to the erasing head 3, past recordings on the magnetic tape are erased by the erasing head, and signals are recorded by the next recording / reproducing head. You. As a current flowing through the coil of the recording head, a current on which an AC signal is superimposed is usually used in order to reduce distortion of a recorded signal. FIG. 7 shows an example of a recording circuit.

[0007]

Normally, when recording a digital signal, an unbiased system for recording the signal itself is used. When recording an analog signal, an AC bias for adding a high-frequency AC component or a DC component to a signal to be recorded is used. There is a system difference that a system and a DC bias system are used, and there is a problem in that the mixed recording of digital and analog signals has to sacrifice the performance of either. That is, the distortion increases in analog recording, and the recording density decreases in digital recording. For example, in the above-described conventional configuration, in digital data recording that is suitable for analog recording but only the signal change point is important,
The phase difference from the bias component (FIG. 8) has a problem that the position of the change point of the signal becomes unclear and the recording density does not increase.

The present invention solves the above problems,
An analog signal recording / reproducing apparatus having an erasing head typified by a tape recorder, capable of recording an analog signal and a digital data signal, and capable of improving recording density and simplifying the apparatus. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION The present invention, in order to achieve the above object, to apply an AC signal and synthesized signal obtained by adding the modulated signal of the digital data synchronized with the AC signal to the recording head Magnetic tape recording device
The AC signal to be recorded is inverted according to the polarity of the modulation signal.
And the change point of the modulation signal is recorded.
Some of the changes in the AC signal
It was done.

[0010]

According to the present invention, the recording medium is improved by the means described above because no jitter occurs due to the phase difference between the AC signal serving as the bias and the digital data modulation signal.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a recording waveform according to the present invention.
AC signal 10 for use as a conventional AC bias
1 shows a modulated wave 102 to be recorded and a composite waveform 103a applied to the recording head.

FIG. 2 is the same as FIG. 1 except that a composite wave 103b is used by using an AC signal inverted according to the polarity of the modulated wave.
Has been generated. According to this method, as shown in FIG. 1, the composite wave is symmetrical at the rise and fall of the change point of the modulation wave, so that the position of the signal change point does not relatively shift in digital recording. FIG.
Further, a part of the change of the AC signal is thinned out and eliminated so that the change point of the signal is easily recorded.

A characteristic of such a composite recording waveform is that the phases of the edges of both the AC signal serving as a bias and the digital modulation signal match. In the conventional AC bias method, the bias waveform and the signal waveform are completely independent, so that a jitter occurs in the composite waveform, and the position of the signal edge becomes indefinite, which causes a decrease in the recording density. According to the recording waveform of the present invention, no jitter occurs in the edge phase, so that a high recording density can be maintained even with the AC bias recording method.

Various waveforms other than those shown in FIGS. 1 to 3 exist, that is, waveforms synchronized so that the phases of the edges of both the AC signal and the digital modulation signal, which are biased, coincide with each other. Any waveform can be used.

Next, a method of generating such a composite recording waveform will be described with reference to the waveform shown in FIG. 2 as an example.

FIG. 4 shows a case in which the modulation input is modulated by the FM or MFM method, and an AC signal inverted by a modulation signal is generated. The modulation signal and the AC signal are added to become an applied signal to the recording head. In FIG. 4, 10 is a modulation circuit, 1
1 is an inverting circuit for generating an inverted AC signal, 12
Is a circuit for generating clocks used in 10 and 11. FIG. 5 shows a timing chart in the circuit of FIG. The frequency corresponding to the data rate after the modulation is 1f, and the frequency 64f, which is 64 times the frequency, is used as the reference for all clocks.

In this circuit, first, a data string before being modulated is inputted while being sequentially shifted to 20, 21 DFFs at a modulation data rate. The modulation circuit 10 uses the FM system and M
The FM system is switched by FM / MFM input. D
The output of the FF 20 is input to the selector 24 and used as modulation data. When 1f is at a high level, FM and M
The operation is divided by FM. FM / MFM for MFM system
Set the input to low level. In the MFM method, when a low level continuously occurs twice as modulated data, a high level must be input between data bits as a clock bit. Therefore, the DFF 20,
From the data string of 21, it is determined whether 0 has continued twice. As a result, when 1f is at a high level, the selector 24
And the next gate circuit 25, D
The signal is input to the modulation circuit of the FF 26. In the case of the FM system, since the clock bit is always at the high level, FM / M
The FM input is fixed at a high level, and the output of the gate circuit 23 is always at a high level. The gate circuit 25 and the DFF 26 invert the output when the input is at a high level, and generate a basic modulation signal to be applied to the recording head. DF
The output of F26 is input to a delay circuit composed of a DFF 27 and an inverter 28, and is delayed by 1 / 64f and used as a modulation output. Further, by forming the modulation output of the DFF 27 and the EMOR of 16f by the gate circuit 29, an AC bias signal inverted by the modulation signal can be generated. Further, an AC bias signal synchronized with the modulation signal can be generated.

The DFF 30 and the inverter 31 are circuits for performing 1/2 frequency division, and generate frequencies from 64f to 32f. Hereinafter, the DFF 32, the inverter 33, 16f, the DFF
34, 8f at the inverter 35, 4f at the DFF 36, the inverter 37, 2f at the DFF 38 and the inverter 39, DF
Ff and the inverter 41 generate 1f. 32f, 1
6f, 2f, and 1f are used for the modulation circuit and the inverting circuit. 32f is mainly used for a delay circuit, 16f is used for a fundamental wave of an AC bias signal, and 2f and 1f are used for modulation timing.

This circuit is an example, and it goes without saying that various changes can be made according to the application. For example, changes such as changing the frequency ratio of each clock, changing the phase relationship, and adding a separate write compensation circuit may be made.

[0021]

According the above embodiment, according to the present invention evident as the present invention, to apply an AC signal and synthesized signal obtained by adding the modulated signal of the digital data synchronized with the AC signal to the recording head Magnetic tape recording device
The AC signal to be recorded is inverted according to the polarity of the modulation signal.
And the change point of the modulation signal is recorded.
Some of the changes in the AC signal
Thus , recording / reproduction of an analog signal and recording / reproduction of a digital signal can be performed by the same recording / reproduction system, and a data recording apparatus with a simple configuration and high recording density can be provided.

[Brief description of the drawings]

FIG. 1 is a waveform diagram of a recording signal according to the present invention.

FIG. 2 is a second recording signal waveform diagram of the present invention.

FIG. 3 is a third recording signal waveform diagram of the present invention.

FIG. 4 is a circuit diagram for generating the waveform of FIG. 2 of the present invention.

FIG. 5 is a waveform chart in the circuit of FIG. 4;

FIG. 6 is a schematic diagram showing a configuration of a conventional analog recording tape recorder.

FIG. 7 is a circuit diagram of a conventional recording circuit.

FIG. 8 is a waveform chart showing a conventional signal phase relationship.

[Explanation of symbols]

 101 AC signal 102 Modulated wave 103a, 103b, 103c Synthetic wave 110 clock

Claims (1)

(57) [Claims] 1. A AC signal and the magnetic tape recording apparatus and a synthesized signal obtained by adding the modulated signal of the digital data synchronized with the AC signal to be applied to the recording head met
The AC signal to be recorded is inverted according to the polarity of the modulation signal.
And the change point of the modulation signal is recorded.
A part of the change of the AC signal so as to be easily
A magnetic tape recording device characterized by being lost.