JPH05159205A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent unerased part from remaining in the case a magnetic tape recorded by an exclusive record head is reproduced by a combination head so as to record and erase its index signal. CONSTITUTION:An operating signal of an operation display panel 23 is supplied to a digital processing circuit 9 through a mode control circuit 22 to form a specified erase signal. Switches 7a, 7b are made ON only during the recording period of the index signal. On the other hand, when the magnetic tape 1 is recorded at a standard transfer speed(SP), it is detected by a reproduction processing circuit 17 and a servo circuit 14. At this time, by changing over a switch 11 with the signal from the servo circuit 14 through the mode control circuit 22, the erase signal from the digital processing circuit 9 is amplified to e.g. the level of three times so as to be supplied to the heads 2a, 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing device such as a VTR or DAT.

[0002]

2. Description of the Related Art In a so-called 8 mm type VTR,
For example, an index (detection) signal for detecting the position of a desired recording signal can be recorded in the search mode. That is, FIG. 5 shows an outline of a main part of the recording format of the 8 mm type VTR. In this figure, an index signal recording area is provided between the video signal recording area and the digital audio signal recording area.

Here, the index signal needs to be recorded and erased during reproduction of, for example, a video signal and a digital audio signal. Therefore, when recording or erasing the index signal, the device in the normal reproduction mode is set to the recording mode only during the period when the recording / reproducing head scans the recording area of the index signal. Then, an index signal or an erase signal is supplied to this head so that recording or erasing is performed by so-called overwriting.

By the way, in such an 8 mm type VTR, recording and reproduction of the magnetic tape are performed at a standard transfer speed (SP) and a transfer speed (LP) lower than the standard transfer speed. In this case, the track pattern on the magnetic tape is changed, and especially the recording track width is changed. That is, in FIG. 6, A shows a track pattern when recorded at a standard transfer speed (SP), and B shows a track pattern when recorded at a low transfer speed (LP).

On the other hand, the standard transfer speed (S
P) and a recording / reproducing operation at a low transfer speed (LP) are performed by using one set of heads as a single unit. In such an apparatus, for example, a head having a recording / reproducing width corresponding to a recording track at a low transfer speed (LP) is used. Therefore, the track pattern in this case is as shown in FIG. 7, for example. That is, A in the figure is the standard transfer speed (S
P) shows the track pattern when recorded, and B in the same figure shows the track pattern when recorded at a slow transfer speed (LP). Here, in the track pattern recorded at the standard transfer speed (SP), a non-recorded area (guard band) is formed between the tracks.

However, in such an apparatus, there is a case where a magnetic tape recorded by an apparatus having a dedicated head having a standard transfer speed (SP) is reproduced. In that case, the relationship between the track pattern and the head is as shown in C of FIG. The broken line in the figure indicates the scanning locus of the head. Here, the reproduction of the video signal, the digital audio signal, and the index signal can be performed without any trouble.

However, in such a device, it may be necessary to cancel the index signal. In that case, if a specified erase signal is supplied to the dual-purpose head to perform the erase, the range of the head scanning locus indicated by the broken line in the figure is erased, but the range corresponding to the above-mentioned guard bands on both sides of the range is erased. It will be erased. Therefore, for example, when an attempt is made to detect a desired index signal in the search mode, there is a possibility that the unerased index signal may be detected and a malfunction may occur.

When the video signal and the digital audio signal are recorded, the erase head wider than the track width when recorded at the standard transfer speed (SP) is used for the preceding erasure, so that the above-mentioned unerased portion does not occur. .. Therefore, the problem of the unerased residue described above is, for example, the standard transfer speed (SP).
The magnetic tape recorded by the dedicated head of No. 2 is reproduced only by the combined head having the standard transfer speed (SP) and the low transfer speed (LP), and the index signal is recorded and erased.

[0009]

The problem to be solved is to use a magnetic tape recorded by a dedicated head having a standard transfer speed (SP) at a standard transfer speed (SP) and a low transfer speed (LP). When reproducing with the dual-purpose head and recording and erasing the index signal, the range of the scanning locus of the head is recorded and erased, but the ranges on both sides are left unerased, and then the desired index is set in the search mode. It is said that when an attempt was made to detect a signal, the unerased signal was detected and there was a risk of malfunction.

[0010]

According to the present invention, the heads 2a, 2b having a recording / reproducing width narrower than the track width at the standard speed are provided.
In the recording / reproducing apparatus using the above, when the recorded magnetic tape 1 is reproduced and the detection signal recorded on the reproduction track is processed (circuit 9), it is supplied to the head at least when the detection signal is erased. The recording / reproducing apparatus is provided with means (amplifier 24, switch 11) for increasing the current value of the current only when processing at the standard speed.

[0011]

According to this, by increasing the current value supplied to the head at the time of erasing the detection signal, the ranges on both sides of the scanning locus of the head are also erased, and the unerased signal is detected and malfunction occurs. You can eliminate fear.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a so-called 8 mm type VTR. In this figure, reference numeral 1 is a magnetic tape, and the magnetic tape 1 is wound around an area of 180 ° or more around the rotary head 2. The digital audio signal is recorded / reproduced within the range of being wound more than 180 °.

Therefore, at the time of recording, a signal from the video input terminal 3 is first supplied to the recording processing circuit 4. The signal from the recording processing circuit 4 is supplied to the switches 5a and 5b, which are alternately selected for each field by the switches 5a and 5b and distributed to two channels. The signals from the switches 5a and 5b are the recording amplifiers 6a and 6a, respectively.
It is supplied to the two heads 2a and 2b of the rotary head 2 through 6b and recording control switches 7a and 7b.

A signal from the voice input terminal 8 is also supplied to the digital processing circuit 9. This digital processing circuit 9
The signal from the FM modulator 10, normally through the switch 11 which is switched to the side shown, switches 5a, 5b.
Is supplied to. Then, the switches 5a and 5b alternately select every one field and distribute to the channel opposite to the above-mentioned video signal.

Further, 12 is a spindle motor for driving the rotary head 2, and 13 is a capstan motor for transferring the magnetic tape 1. The spindle motor 12 and the capstan motor 13 are servo-operated by a servo circuit 14, respectively. When recording, the recording processing circuit 4
Supplies the synchronizing signal of the input video signal to the servo circuit 14, drives the motors 12 and 13 in synchronization with the input video signal, and controls the switching of the switches 5a and 5b.

On the other hand, during reproduction, signals from the two heads 2a and 2b of the rotary head 2 are supplied to the switch 16 through the reproduction amplifiers 15a and 15b, respectively.
The switch 16 is switched by the servo circuit 14 every 180 ° rotation of the rotary head 2, and the video signals distributed to the two channels are continuously taken out. The signal from the switch 16 is supplied to the reproduction processing circuit 17, and the signal from the reproduction processing circuit 17 is supplied to the video output terminal 1.
8 is taken out. A control signal in the reproduced video signal is supplied from the reproduction processing circuit 17 to the servo circuit 14, and the drive of the capstan motor 13 is controlled by this control signal to perform tracking control.

Further, signals from the reproduction amplifiers 15a and 15b are supplied to a switch 19, and the switch 19 is switched to the opposite side of the switch 16 every 180 ° rotation of the rotary head 2 by the servo circuit 14. The signal from the switch 19 is supplied to the digital processing circuit 9 through the FM demodulator 20, and the signal from the digital processing circuit 9 is taken out to the audio output terminal 21.

Further, 22 is a mode control circuit, which operates in response to an operation signal from the operation display panel 23, such as recording, reproduction, search, and standard transfer speed (SP) or slower transfer speed (LP). Is determined. Then, the signal from the mode control circuit 22 is supplied to the servo circuit 14, and the control according to the determined operation mode is performed.
Further, the digital processing circuit 9 performs predetermined processing.

In this apparatus, when the index (detection) signal is recorded in the recording or reproducing mode, the operation display panel 23 is operated. As a result, this operation signal is supplied to the digital processing circuit 9 through the mode control circuit 22, and a predetermined index signal is formed and recorded on the magnetic tape 1 for a predetermined period. In the playback mode, recording is performed by turning on the switches 7a and 7b only for a predetermined period.

In the search mode using the index signal, the reproduction signal being searched is supplied to the digital processing circuit 9. When the predetermined index signal is reproduced, this detection signal is supplied to the servo circuit 14 through the mode control circuit 22 to stop the transfer of the magnetic tape 1.

When the index signal is erased in the reproduction mode, the operation display panel 23 is operated. As a result, this operation signal is supplied to the digital processing circuit 9 through the mode control circuit 22, and a predetermined erase signal is formed. Further, the switches 7a and 7b are turned on only during the recording period of the index signal, so that the magnetic tape 1
The predetermined period of is deleted.

Further, in this apparatus, when the magnetic tape 1 is recorded at the standard transfer speed (SP), the reproduction processing circuit 17 and the servo circuit 14 detect it. When the index signal is erased from the magnetic tape 1 recorded at the standard transfer speed (SP), the switch 11 is switched in the opposite direction to that shown in the drawing.
The erasing signal from the digital processing circuit 9 is amplified by the amplifier 24 to, for example, a triple level, and erasing is performed.

That is, in this apparatus, when recording and erasing the index signal in the reproduction mode, for example, the reproduction signal from the heads 2a and 2b as shown in FIGS. , Switch 7 as shown in D
a and 7b are turned on. The recording signal of the index signal is, for example, 5.8 MHz and 2.
The erase signal is formed of a 1-wave FM signal of 9 MHz, and the erase signal is formed of a continuous signal of 5.8 MHz, for example, as shown in B of FIG. When the index signal is erased when the magnetic tape 1 is recorded at the standard transfer speed (SP), the erase signal is amplified to, for example, a triple level as shown in C of FIG. ..

Therefore, in this apparatus, when the index signal is erased by reproducing the magnetic tape recorded by the apparatus having the dedicated head having the standard transfer speed (SP) as shown in FIG. Is amplified to, for example, a tripled level to be expanded to both sides of the head 2a or 2b, and erasing is performed up to both sides of the scanning loci of the heads 2a and 2b.

Thus, according to the above-described apparatus, by increasing the current value supplied to the heads 2a and 2b (amplifier 24) at the time of erasing the detection signal, the ranges on both sides of the scanning locus of the head are also erased and the unerased remains. It is possible to eliminate the possibility that the generated signal may be detected and cause a malfunction.

In the above apparatus, the index signal is recorded at a specified level. In that case, even if there is an unrecorded portion on both sides of the scanning loci of the heads 2a and 2b, reproduction and detection can be performed without any problem. In addition, the magnetic tape 1 uses a dual-purpose head and has a standard transfer speed (S
When recorded in P), guard bands are generated on both sides of the scanning locus, so there is no problem even if erasing is performed at a triple level.

Further, this apparatus can be applied to DAT and the like for recording / reproducing digital signals by using a rotary head.

[0028]

According to the present invention, by increasing the current value supplied to the head at the time of erasing the detection signal, the ranges on both sides of the scanning locus of the head are erased, and the unerased signal is detected. It is now possible to eliminate the risk of malfunction.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an example of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a timing chart diagram for explaining the explanation.

FIG. 3 is a waveform diagram of a signal for explaining it.

FIG. 4 is a diagram showing a track pattern for the description.

FIG. 5 is a diagram for explaining an index signal.

FIG. 6 is a diagram for explaining a track pattern.

FIG. 7 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 1 magnetic tape 2 rotary heads 2a, 2b head 3 video input terminal 4 recording processing circuit 5a, 5b, 11, 16, 19 switch 6a, 6b recording amplifier 7a, 7b recording control switch 8 audio input terminal 9 digital processing circuit 10 FM modulation Device 12 Spindle motor 13 Capstan motor 14 Servo circuit 15a, 15b Reproduction amplifier 17 Reproduction processing circuit 18 Video output terminal 20 FM demodulator 21 Audio output terminal 22 Mode control circuit 23 Operation display panel 24 Amplifier

Claims (1)

[Claims] 1. A recording / reproducing apparatus using a head having a recording / reproducing width narrower than a standard speed track width, when reproducing a recorded magnetic tape and processing a detection signal recorded on this reproducing track. A recording / reproducing apparatus comprising means for increasing the current value supplied to the head at least when the detection signal is erased only during the processing at the standard speed.