JP2841850B2 - Magnetic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Field of application in industry B Outline of the invention C Conventional technology D Problems to be solved by the invention E Means to solve the problem (FIGS. 1 and 2) F function (FIGS. 1 and 2) G Embodiment (FIGS. 1 and 2) (G1) Configuration of Embodiment (G2) Operation of Embodiment (G3) Effects of Embodiment (G4) Other Embodiments Effects of H Invention A Industrial Application Field The present invention relates to a magnetic recording apparatus, and can be applied to, for example, a digital audio tape recorder that sequentially records digital audio signals on a magnetic tape diagonally.

B. Summary of the Invention The present invention relates to a magnetic recording apparatus, in which, at the start of recording, during a period until a relative speed of a recording medium with respect to a magnetic head rises to a predetermined value, a predetermined signal that becomes silent when reproduced is used instead of a digital signal. By recording the recording signal of
At the time of reproduction, generation of abnormal noise can be effectively avoided.

C. Prior Art Conventionally, in a magnetic recording apparatus, there is a magnetic recording apparatus in which a recording track is sequentially formed diagonally on a magnetic tape to record a digital audio signal (hereinafter, referred to as a digital audio tape recorder).

In this type of digital audio tape recorder, at the time of recording, a digital audio signal is blocked at a predetermined period and then subjected to an interleave process.

Further, the digital audio tape recorder adds a code for error detection and correction to the interleaved digital audio signal, and records it on a predetermined recording track for each block.

On the other hand, at the time of reproduction, the digital audio tape recorder performs an error detection and correction process on reproduction data obtained from each recording track.

In the error detection and correction processing, the digital audio tape recorder performs interpolation processing on a portion where error cannot be corrected, and corrects reproduced data so as to mute a portion where an error occurs at a predetermined value or more.

Further, the digital audio tape recorder performs a deinterleaving process on the reproduced data on which the error detection and correction have been performed, converts the reproduced data into an analog signal, and outputs the analog signal.

Thus, in the digital audio tape recorder, a digital audio signal can be recorded at a high density on a magnetic tape, and can be reproduced while effectively preventing sound quality deterioration.

D. Problems to be Solved by the Invention Meanwhile, in this type of digital audio tape recorder, there is a digital audio tape recorder in which a magnetic tape is pressed against a magnetic tape traveling system by a pressing force of an operator to perform recording and reproduction.

When overwriting and recording with such a digital audio tape recorder, there is a problem that an unpleasant noise is generated at the start of overwriting and recording at the time of reproduction.

That is, in such a digital audio tape recorder, it takes time for the rotation speeds of the drum motor and the capstan motor to rise to a steady state, so that it is difficult to maintain the correct recording wavelength at the start of recording. is there.

That is, immediately after the start of recording, recording is performed at a short recording wavelength, and the recording wavelength gradually changes to a correct recording wavelength.

Accordingly, at the time of reproduction, an error occurs in accordance with the change in the recording wavelength at the start of the overwrite recording, and the reproduced data is interpolated gradually from silence and output as the error occurrence frequency decreases. Become like

Accordingly, the reproduction data is deinterleaved and output, so that in the actual reproduction signal,
Silencing and interpolation are repeated, resulting in an unpleasant noise.

As one method for solving this problem, a method of interrupting the supply of the recording current until the magnetic tape traveling system rises to a steady state can be considered.

However, in this case, an unerased portion occurs during a period until the magnetic tape traveling system rises to a steady state.

Therefore, when the overwriting recording is repeated, an unerased digital audio signal is reproduced for a moment, making it difficult to hear.

In addition, there is a problem that the tracking operation is disturbed at the rising edge of the re-recorded portion, so that it is not possible to reproduce correctly.

The present invention has been made in view of the above points, and has as its object to propose a magnetic recording device capable of effectively avoiding the generation of abnormal noise and performing overwriting recording.

E To solve the problem, in the present invention, in the magnetic recording apparatus 1 for sequentially recording a desired digital signal S2 on a predetermined recording medium 22, the digital signal S2 is recorded on the recording medium 22.
Magnetic heads 14A and 14B to be recorded on magnetic heads 14A and 14B
So that the relative speed of the recording medium 22 with respect to
A drive system 18 for driving the magnetic heads 14A, 14B and / or the recording medium 22 at a predetermined speed, and recording signal output circuits 4, 6, 8, 10, 30 for supplying a digital signal S2 to the magnetic heads 14A, 14B; The recording signal output circuits 4, 6, 8, 10, 30 perform reproduction instead of the digital signal S2 during the period until the relative speed of the recording medium 22 with respect to the magnetic heads 14A, 14B rises to a predetermined speed at the start of recording. Recording signal SM that is silent when
Is supplied to the magnetic heads 14A and 14B.

F action During the period until the relative speed of the recording medium 22 with respect to the magnetic heads 14A and 14B rises to a predetermined speed, the digital signal
By recording the recording signal SM that is silent when reproduced instead of S2, it is possible to effectively avoid the generation of abnormal noise during reproduction.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(G1) Configuration of the Embodiment In FIG. 1, reference numeral 1 denotes a digital audio tape recorder as a whole, which converts an analog audio signal S1 into a digital signal (hereinafter referred to as a digital audio signal) S2 and records it.

That is, the digital audio tape recorder 1
The audio signal S1 is converted to an analog digital conversion circuit (A /
D) 2, where it is converted to a digital audio signal S2.

The modulation circuit 4 inputs the digital audio signal S2 via the selection circuit 6 and converts the digital audio signal S2 into a predetermined interleave cycle (30 in the standard time mode).
[Msec]).

Further, the modulation circuit 4 sequentially stores the block-formed digital audio signal S2 in a predetermined area of a memory circuit (not shown), whereby the digital audio signal S2 is stored.
Are interleaved at a predetermined cycle.

Further, the modulation circuit 4 generates a parity code for error detection and correction with respect to the digital audio signal S2 stored in the memory circuit, and then sequentially performs 8-10 modulation with predetermined subcode data, thereby generating a recording signal S3. .

Further, the modulation circuit 4 sequentially outputs the generated recording signal S3 to the recording amplification circuit 10 via the selection circuit 8.

The recording amplifier circuit 10 rises to an operating state when the control signal SC1 output from the system control circuit 12 rises,
The recording signal S3 is amplified and output to the magnetic heads 14A and 14B.

The magnetic heads 14A and 14B are arranged at an angular interval of 180 degrees on the rotating drum 16, and the rotating drum 16
Are wound at a winding angle of 90 degrees.

When the output signal SC2 output from the system control circuit 12 rises, the servo circuit 18 rises to an operation state and drives the drum motor.

At this time, the servo circuit 18 drives the drum motor at a predetermined speed based on the rotation phase signal PG and the rotation frequency signal FG output from the drum motor.

The drum motor drives the rotary drum 16 to rotate, and also drives the capstan 20 via a predetermined gear.

Thus, in the digital audio tape recorder 1, the rotary drum 16 and the capstan 20 are driven at a predetermined rotation speed by one drum motor, and the magnetic head
14A and 14B are formed so as to form a recording track on the magnetic tape 22 sequentially and diagonally.

Further, at the time of reproduction, the servo circuit 18 switches the gear for transmitting the driving force of the drum motor to the capstan 20 and drives the drum motor at a rotation speed approximately twice that at the time of recording, so that the magnetic heads 14A and 14B The rotating drum 16 and the capstan are used to scan the recording track multiple times.
Drive 20.

Thus, in the digital audio tape recorder 1, during reproduction, reproduction data is obtained from each recording track a plurality of times, and only the reproduction data without error is selectively output, so that the reproduction is reliably performed without the tracking control. Have been made to gain.

Further, the servo circuit 18 detects the rotation speed of the rotating drum 16 based on the rotation phase signal PG and the rotation frequency signal FG, and when the relative speed of the magnetic tape 22 with respect to the magnetic heads 14A and 14B becomes a predetermined value, the system control circuit. The lock signal SR is output to 12.

As shown in FIG. 2, when the recording operator 26 is pressed at time t0, the system control circuit 12 switches to the recording mode, and raises the control signals SC1 and SC2, respectively (see FIG. 2).
Figure (A)).

As a result, the system control circuit 12 brings the recording amplifier circuit 10 and the servo circuit 18 into an operating state.

At this time, the digital audio tape recorder 1
In, the magnetic tape 22 is pressed and held against the rotating drum 16 and the capstan 20 using the pressing force of the operator.

Thus, in the digital audio tape recorder 1, the magnetic tape 22 is run while being wound around the rotary drum 16, and the magnetic tape running system is configured with a simple configuration as a whole.

Thus, in the rotating drum 16, at time t0, the operating element 26
Is pressed, the rotation speed N gradually rises (FIG. 2 (B)), and after a predetermined period elapses, rises to the steady speed.

Further, the system control circuit 12 outputs a control signal SC3 to the selection circuit 8 at a time point t0 (FIG. 2 (C)), and supplies a mute signal SM to the recording amplification circuit 10 instead of the recording signal S3.

Here, the mute signal SM is a tone signal of a fixed frequency at which an error is detected during reproduction, and is generated by the reference signal generation circuit 30 together with the system clock signal of the digital audio tape recorder 1 and the like.

As a result, in the digital audio tape recorder 1, at the start of recording, a digital audio signal is output.
Instead of S2, a signal SM that is reliably detected as an error when reproduced is recorded.

Further, based on a built-in timer, the system control circuit 12 receives a control signal at a time t1 when a predetermined period has elapsed from the time t0.
SC3 and SC4 are output (FIG. 2 (D)), and the contacts of the selection circuits 6 and 8 are switched.

As a result, the system control circuit 12 records the digital audio signal held at the 0 level instead of the mute signal SM.

Further, the system control circuit 12 outputs the lock signal SR at time t2.
Rises, the contact of the selection circuit 6 is switched, and recording of the digital audio signal S2 is started.

As a result, in the digital audio tape recorder 1, the magnetic heads 14A and 14B
Time t2 when the relative speed of the magnetic tape 22 with respect to
During this period, 0-level digital data is recorded following the mute signal SM.

In this way, in the section in which the mute signal SM is recorded, an error is continuously detected during reproduction, so that the reproduction signal is muted and output.

In the subsequent section in which the 0-level signal is recorded, the frequency of interpolation gradually decreases as the time point t2 approaches, and is output.

Since the original audio data recorded at this time is held at the 0 level, the reproduced signal is interpolated to the 0 level and output.

On the other hand, in the section in which the SM is recorded as the silence signal, the silence is reliably silenced and output even when the recording wavelength changes.

Therefore, even in the case of performing the deinterleaving processing and outputting, in the section from time t0 to time t2, a reproduced signal held at the 0 level can be obtained, thus effectively avoiding generation of abnormal noise during reproduction. be able to.

Further, as compared with the case where the supply of the recording signal is controlled to be stopped, the occurrence of the unerased portion can be effectively avoided, and the occurrence of abnormal noise can be effectively avoided accordingly.

In particular, in a reproduction system that scans one recording track a plurality of times and selectively outputs only error-free reproduction data, such as the digital audio tape recorder 1, a zero level signal follows the silence signal SM. By recording the audio data, it is possible to surely obtain the reproduction data in which the mute or the 0 level is maintained at the overwriting recording start portion, and it is possible to effectively avoid the generation of the abnormal sound.

Further, in a reproducing system in which the sub-code data is detected to detect a portion where the original signal is recorded and to mute the portion before the overwrite recording, the recording is performed in this embodiment. When reproducing the magnetic tape, it is possible to reliably detect the rising portion of the overwritten portion, and to surely reduce the generation of abnormal noise.

(G2) Operation of Embodiment In the above configuration, the audio signal S1 is converted into a digital audio signal S2 by the analog-to-digital conversion circuit 2, and then converted to a recording signal S3 by the modulation circuit 4 via the selection circuit 6. .

The recording signal S3 is output to the magnetic heads 14A and 14B via the selection circuit 8 and the recording amplification circuit 10 in order, so that the digital audio signal S2 can be sequentially recorded on the magnetic tape 22.

At the start of the recording, the contacts of the selection circuits 6 and 8 are switched, so that the mute signal SM is recorded instead of the recording signal S3 during the period from the time t0 to the time t1 of the recording start. During a period from t1 to a time point t2 when the speed rises to the predetermined speed, audio data held at the 0 level is recorded.

As a result, the mute signal SM and the audio data held at the 0 level are recorded and reproduced during the period from the start of recording until the relative speed of the magnetic tape 22 with respect to the magnetic heads 14A and 14B reaches a predetermined value. Generation of abnormal noise can be effectively avoided.

(G3) Effects of the Embodiment According to the above configuration, the mute signal SM and the zero level are held at the start of recording until the relative speed of the magnetic tape 22 with respect to the magnetic heads 14A and 14B reaches a predetermined value. By recording the audio data, it is possible to effectively avoid the occurrence of abnormal noise during reproduction, and to perform overwriting recording.

(G4) Other Embodiments In the above embodiment, the case where audio data held at the 0 level is recorded following the mute signal has been described. However, the present invention is not limited to this, and mute may be performed as necessary. Only a signal may be recorded.

Further, in the above-described embodiment, the case where the rotating drum and the capstan are driven by one drum motor has been described. However, the present invention is not limited to this, and the present invention is widely applied to the case where the rotating drum and the capstan are each driven by a dedicated motor. Can be applied.

On the contrary, the present invention can be widely applied to a case where a magnetic tape is run by a reel motor instead of the capstan.

Furthermore, in the above-described embodiment, a case has been described in which, at the time of reproduction, each recording track is scanned a plurality of times to obtain a reproduction signal. However, the present invention is not limited to this. It can be widely applied to cases.

In particular, when tracking control is performed by recording a pilot signal for a tracking servo, if a mute signal or audio data held at the 0 level is recorded together with the pilot signal as in this embodiment, the overwriting recording is started. The tracking control can be surely performed for the portion.

Furthermore, in the above-described embodiment, a case has been described in which a digital audio signal is recorded using a magnetic head mounted on a rotating drum. However, the present invention is not limited to this, and for example, a plurality of fixed magnetic heads are used. The present invention can be widely applied to a case where a digital audio signal is recorded.

H Effect of the Invention As described above, according to the present invention, at the start of recording, during a period until the drive system is stabilized, instead of a digital signal, a predetermined recording signal that is silent when reproduced is recorded. Thus, it is possible to obtain a magnetic recording apparatus capable of effectively avoiding generation of abnormal noise during reproduction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a digital audio tape recorder according to an embodiment of the present invention, and FIG. 2 is a signal waveform diagram for explaining its operation. 1 ... Digital audio tape recorder, 4 ... Modulation circuit, 6, 8 ... Selection circuit, 12 ... System control circuit, 14A, 14B ... Magnetic head, 18 ... Servo circuit, 22 ...
…Magnetic tape.

Claims (1)

(57) [Claims] 1. A magnetic recording apparatus for sequentially recording a desired digital signal on a predetermined recording medium, comprising: a magnetic head for recording the digital signal on the recording medium; and a relative speed of the recording medium with respect to the magnetic head being a predetermined value. A driving system for driving the magnetic head and / or the recording medium at a predetermined speed, and a recording signal output circuit for supplying the digital signal to the magnetic head, wherein the recording signal output circuit starts recording. At this time, during the period until the relative speed of the recording medium with respect to the magnetic head rises to the predetermined speed, instead of the digital signal, a recording signal that is silent when reproduced is supplied to the magnetic head. Magnetic recording device.