JPH0375934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention dramatically increases recording density in a fixed head type magnetic recording and reproducing device that records and reproduces PCM signals, etc. using a plurality of magnetic heads arranged in the width direction of a magnetic tape. The present invention relates to a head position adjustment device that can be improved.

As a magnetic recording and reproducing device for PCM signals, a so-called fixed head system is used that performs recording and reproducing using multiple magnetic heads arranged in the width direction of a magnetic tape.
PCM tape recorders are known. Note that hereinafter, an assembly of these plural magnetic heads will be referred to as a multitrack head. In this type of magnetic recording/reproducing device, in order to prevent a decrease in the signal-to-noise ratio or an increase in crosstalk, the relative relationship between the track on the magnetic tape and the magnetic head corresponding to the track in the width direction of the magnetic tape is It is necessary to suppress the positional deviation to an extremely small value (for example, several tens of μm). Therefore, in this type of magnetic recording/reproducing device, when a small and simple magnetic tape such as a compact cassette tape is used as a recording medium, the mechanical precision of the tape running system is poor, so it is necessary to reduce the relative positional deviation. On the other hand, since the tape width becomes narrower, it is extremely difficult to improve the recording density by increasing the number of tracks (that is, decreasing the track pitch).

By the way, this type of magnetic recording and reproducing apparatus records and reproduces a time code signal for knowing the current running position of the magnetic tape on a specific track on the magnetic tape, and usually this time code signal is , for example, a signal that continues at a constant level, such as an SMPTE code signal recorded by the FM method or the MFM method.

This invention has been made in view of the above circumstances, and is a fixed head type magnetic recording and reproducing apparatus that records and reproduces digital signals such as PCM signals using a plurality of magnetic heads arranged in the width direction of a magnetic tape. A head position adjustment device that can be applied to multi-track heads of normal standards and that can always reduce the relative positional deviation in the tape width direction between each magnetic head and its corresponding track on a magnetic tape to almost zero. In a magnetic recording and reproducing apparatus that records and reproduces signals using a plurality of magnetic heads arranged in the width direction of a magnetic tape, two of the plurality of magnetic heads Level detection for detecting the level of each reproduced signal output from each magnetic head corresponding to each track on both sides of the magnetic tape where a signal of a certain level is recorded and where no signal is recorded. and control means for controlling the relative position between the magnetic head and the magnetic tape in the width direction of the magnetic tape so that the levels of the reproduction signals detected by the level detection means are equal. It is what it is.

Hereinafter, the head position adjustment device according to the present invention will be explained.
An embodiment applied to a PCM tape recorder will be described in detail with reference to FIGS. 1 and 2.

In FIG. 1, 1 is a magnetic tape, and this magnetic tape 1 is designed to run in the direction of arrow Y. Reference numeral 2 designates a multitrack head for reproduction, and this multitrack head 2 is provided so as to be movable in the width direction of the magnetic tape 1 (in the direction of arrow X or the direction opposite to arrow X). n reproduction heads 3 _-1 to 3 _-o are arranged in the width direction of the magnetic tape 1. The i-th playback head 3 _-i among these playback heads 3 _-1 to 3 _-o is a playback head for time code signals, and playback heads 3 _-(i-1) and 3 _-(i+1) are , is a reproduction head adjacent to reproduction head 3 _-i .

Next, numeral 4 is a multi-track head for recording, and this multi-track head 4 has recording heads 5-1 to _5-1 corresponding to the playback heads _3-1 to 3 _-o , respectively.
5 _-o are arranged, and these recording heads _5-1 to 5 _-o record the corresponding tracks _6-1 on the magnetic tape 1.
~6 It is now possible to record PCM signals etc. on _-o . Here, i at recording heads 5 _-1 to 5 _-o
The recording head 5 _- i is a recording head specifically for time code signals. During recording, a time code signal such as an SMPTE code signal is supplied to this recording head 5-i via a recording amplifier 7, and this time code signal is Track 6 _-i is now recorded using FM or MFM methods. In addition,
No recording is made on tracks 6- _(i-1) and 6- _(i+2) .

Next, 8 and 9 are both level detectors (level detection means), and level detector 8 corresponds to the leakage signal level of the time code signal of track 6 _-i that is reproduced by playback head 3 _-(i-1). The level detector 9 converts the leakage signal level of the time code signal of the track 6 _-i reproduced by the playback head 3 _-(i+1) into a corresponding voltage and outputs the same. It's getting old. 10 is the level detector 8,
A comparison circuit 9 compares the output voltages V ₁ and V ₂ , and a motor 11 is driven by the output signal of the comparison circuit 10 . The rotation of the motor 11 is transmitted to the multi-track head 2 through a connection mechanism (not shown), and when the motor 11 rotates forward or reverse, the multi-track head 2 moves in the direction of arrow X or in the direction opposite to arrow X. It's becoming like that. In this case, the comparator circuit 10 and the motor 11 constitute the control means in this invention.

Note that 12 is a decoder for decoding the time code signal of track 6 _-i that is reproduced by playback head 3 _-i , and 13 is a display that displays information indicating the current running position of magnetic tape 1 based on the output of this decoder 12. It is a device. 14 is the playback head 3 _-1
Playback head 3 _{-(i-1) ,} 3 _-i , 3 _{-(i+1) at ~3 -o}
This is a PCM signal processing circuit that processes PCM signals that are reproduced by a reproduction head other than the PCM signal.

Next, the operation of this head position adjusting device having the above structure will be explained. First, it is assumed here that a time code signal has already been recorded on track 6 _-i , and that the recorded signal of magnetic tape 1 is currently being played back. In this case, magnetic tape 1
However, playback head 3 _-1 ~ 3 _-o and track 6 _{-1 ~} 6 _-o
deviates from the accurately corresponding reference position (position with zero relative position deviation) by △X in the X direction, the output voltage V ₁ of the level detector 8 changes to It changes as shown by solid line a. Similarly, the output voltage V ₂ of the level detector 9 changes as indicated by the solid line b in FIG. 2 in accordance with the relative position deviation ΔX. That is, in this case, each playback head 3 _-1 to 3 _-o
When a relative positional deviation △X occurs between the track and the corresponding tracks _6-1 to 6 _-o , the comparator circuit 10 outputs a signal according to the amount and sign (direction) of this deviation △X. The motor 11 is driven by the signal. As a result, the multitrack head 2 is moved so that the deviation ΔX becomes zero.

As described above, according to this embodiment, even if the traveling path of the magnetic tape 1 changes in the tape width direction, each reproduction head 3 _-1 to 3 _-o and the corresponding track 6 _-1 to
6 _- The relative positional deviation △X from -o is always kept at zero.

In the above embodiment, the multitrack head 2 is moved to follow the fluctuation of the magnetic tape 1, but the multitrack head 2 is fixed and the running path of the magnetic tape 1 is changed according to the relative position deviation. The movement may be controlled so as to make it zero.

As is clear from the above description, the head position adjustment device according to the present invention can be used in a magnetic recording/reproducing apparatus that records and reproduces signals using a plurality of magnetic heads arranged in the width direction of a magnetic tape. Output from two magnetic heads of the magnetic heads corresponding to the tracks on both sides of the magnetic tape on which a signal of a certain level is recorded, and on which no signal is recorded. level detecting means for detecting the levels of each reproduced signal, and adjusting the relative position between the magnetic head and the magnetic tape so that the levels of the reproduced signals detected by the level detecting means are equal. Since the control means for controlling in the width direction is provided, the relative positional deviation between each of the plurality of magnetic heads and the corresponding track on the magnetic tape can always be made substantially zero. Therefore, if the head position adjustment device according to the present invention is provided, even in a magnetic recording/reproducing device using a small magnetic tape such as a compact cassette tape, the track pitch can be reduced and the recording density can be dramatically improved. I can do it. In addition, a magnetic head corresponding to a track on which a signal of a certain level is recorded and each magnetic head corresponding to each track on both sides of the track on which no signal is recorded are magnetic heads in a normal standard multi-track head. This can be realized by three magnetic heads arranged in the width direction of the tape. Therefore, the present invention has the advantage that it can be applied to multi-track heads of ordinary standards. Naturally, it is also possible to construct a normal magnetic recording and reproducing apparatus that does not perform position adjustment by using each magnetic head corresponding to a track on which no signal is recorded according to the present invention as a normal magnetic head for reproducing. The present invention
Since the position control is performed by the output of each magnetic head corresponding to the track where no signal is recorded, that is, the position control is performed by detecting no signal, it is possible to perform position control even in situations where burst errors occur due to dust etc. adhering to the tape. , almost no malfunctions occur,
Stable position control can be performed. Further, according to the present invention, there is no need to provide a dedicated track for obtaining position information, so there is an advantage that the track is not wasted.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the structure of an embodiment of a head position adjusting device according to the present invention, and FIG. 2 is a waveform diagram for explaining the embodiment. 1... Magnetic tape, 2... Multi-track head for playback, 3 _-1 to 3 _-o ... Playback head, 4...
Multitrack head for recording, _5-1 to 5 _-o ...
Recording head, 6 _-1 ~ 6 _-o ... Track, 8, 9...
... Level detection means (level detector), 10 ... Comparison circuit, 11 ... Motor.

Claims (1)

[Claims] 1. In a magnetic recording and reproducing device that records and reproduces signals using a plurality of magnetic heads arranged in the width direction of a magnetic tape, two of the plurality of magnetic heads are arranged in the width direction of the magnetic tape. Level detection means for detecting the level of each reproduction signal output from each magnetic head corresponding to each track on both sides of a track on which a signal of a certain level is recorded, and on which no signal is recorded; and this level detection means. a head position adjusting device comprising: control means for controlling a relative position between the magnetic head and the magnetic tape in the width direction of the magnetic tape so that the levels of the reproduction signals detected by the magnetic head and the magnetic tape are equal to each other;