JPS6232343Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking device in a magnetic tape recording/reproducing device having a plurality of tracks.

Conventionally, a precision tape guide has been used as a means for preventing track misalignment between a recording track and a magnetic head during reproduction of a magnetic tape. However, it has been difficult to completely prevent track deviation using this method alone. For example, in the case of compact cassette tape, from the tape width
There is a tolerance of 5 .mu.m from 3.805 mm to 3.810 mm, and therefore, no matter how precise a tape guide is used, it is difficult to guarantee that the track deviation is less than 5 .mu.m. In addition, track deviations from the recorded track also occur due to playback of tapes recorded with other recorders, variations in the precision of the cassette halves, or changes in the tape running direction. For this reason, especially in magnetic tape recording and reproducing devices that have a large number of tracks and one track width is very narrow, even a slight track deviation can have a large effect on the playback output, so conventional methods using tape guides cannot be used. I was unable to obtain satisfactory playback.

Another method is to provide an auxiliary head with a width half the track width of the signal recording/reproducing head on the side of the signal recording/reproducing head, as described in Japanese Patent Laid-Open No. 56-80822. 1/2 of output
There is a method that performs tracking control based on the magnitude relationship between the value of the output of the auxiliary head and the value of the output of the auxiliary head. However, in such a method, since the auxiliary head reproduces a different signal on the time axis than the signal recording/reproducing head, a tracking error signal may be generated even if the head is in the correct position with respect to the track. It was difficult to perform accurate tracking.

The present invention was developed in view of the above points, and its purpose is to avoid being affected by tape width tolerances, variations in the accuracy of tape guides and cassette halves, and to be able to produce a recording device that is compatible with other recorders. To provide a tracking device capable of obtaining stable playback output without track deviation even when playing back a recorded tape.

The present invention will be explained below with reference to examples. 1st
The figure is a diagram showing the overall outline of one embodiment,
The magnetic tape 1 is guided with respect to a reproducing magnetic head 4 by tape guides 2 and 3. The output of the reproducing magnetic head 4 is taken out as a reproducing output and also as a tracking output, and the latter is input to a tracking error detection circuit 5.
The detection output of the error detection circuit 5 is sent to a drive circuit 6 including a phase compensation circuit, and this drive circuit 6 drives the head vibration mechanism 7 to vibrate and track the reproducing magnetic head 4. There is. 71
72 is a push rod for moving the reproducing magnetic head 4 in the tape width direction; 72 is the push rod 71;
This is a damper that regulates the reference position of the reproducing magnetic head 4 by holding it in a predetermined position.

According to such a configuration, even if the recording track is recorded in a meandering manner during recording, track deviation is directly detected, and the deviation is compensated for by the vibrating mechanism 7 of the head.

FIG. 2 is an explanatory diagram for detecting track deviation. Signals are recorded on the magnetic tape 1 on n tracks, and the magnetic head 4 also has n tracks with the same track width as the magnetic tape 1. The first channel is composed of two channels 41A and 41A with fine boundaries.
41B, the n-th channel is also formed by two similar channels 4nA and 4nB, and both channels are located on the same time axis (on the same line perpendicular to the track). Incidentally, the same tracking control signal is recorded on the tracks 11A and 11B, 1nA and 1nB, which are in contact with the magnetic tape 1, respectively.

Further, the error detection circuit 5 is connected to the reproducing magnetic head 4.
The amplifier 51 detects the difference between the outputs of tracks 41A and 41B, the amplifier 52 detects the difference between the outputs of tracks 4nA and 4nB, and the amplifier 53 adds the outputs of both amplifiers 51 and 52.

Now, suppose that the recording track of the magnetic tape 1 slightly deviates downward in the drawing with respect to the reproduction magnetic head 4, the reproduction output of the channel 41A of the reproduction magnetic head 4 decreases, but the reproduction output of the channel 41B decreases. Output does not change. Conversely, if the recording track of the magnetic tape 1 slightly deviates upward in the drawing with respect to the reproducing magnetic head 4, the reproducing output of the track 41A does not change, but the reproducing output of the channel 41B decreases. Then,
By detecting the difference between the reproduction outputs of the channels 41A and 41B using the amplifier 51, the direction and magnitude of the track deviation can be determined. In the above case, channels 4nA and 4nB of the reproducing magnetic head 4
A similar change in the reproduction output occurs in the amplifier 5.
A similar signal is obtained at 2. Therefore, an overall tracking error signal is obtained from the amplifier 53 which adds the outputs of both amplifiers 51 and 52. If the number of tracks for error detection is increased, the recording signal will be less susceptible to dropouts and the like, and the reliability of tracking error signal detection will improve. Further, the recording signal of the track for error detection may be a signal of a constant level exclusively used for error detection, and in the case of digital recording, the information track may also be used as it is for error detection. Also, this method
The magnetic head may also be used for both recording and reproduction.

FIG. 3 is an explanatory diagram for detecting track deviation in another example, in which the magnetic head 40 is connected to the recording channels 41' to 41n' and the reproducing channel 4.
1'' to 4n'', and reproduction channels 41'' to 4n'' are arranged on the forward side in the tape running direction, and the reproduction channels 41'' and 4n'' are arranged as recording channels 41' and 4n'', respectively. 4n', and the reproduction channel 41'' was made to coincide with the inner edge of the recording track 41', and the reproduction channel 4n'' was made to coincide with the outer edge of the recording channel 4n'. It is something. The error detection circuit 5 includes an amplifier 54 that detects the difference between the outputs of the reproduction channels 41'' and 4n''.

In the example shown in FIG. 3, if the magnetic tape 1 is slightly shifted downward in the drawing with respect to the magnetic head 40, the reproduction output of the reproduction channel 41'' does not change, but the reproduction output of the reproduction channel 4n'' does not change. When the output decreases and, conversely, shifts upward, the reproduction output of the reproduction channel 41'' decreases, and the reproduction output of the reproduction channel 4n'' remains unchanged. Therefore, by detecting the difference between the reproduction outputs of both reproduction channels 41'' and 4n'' using the amplifier 54, the direction and magnitude of the track deviation can be known.

In addition, in this method, any track other than the recording tracks 11 and 1n can be used as an error detection track, and in order to improve reliability, multiple sets of two tracks are used as one set, and those error detection tracks are used. It is sufficient to add the detection signals. Further, the recording signal may be a constant level signal exclusively used for error detection, and in the case of digital recording, the information track may also be used for error detection.

FIG. 4 is a diagram showing the structure of the magnetic head drive section. The magnetic head 4 is fixed to a holder 21, and this holder 21 is connected to the base 2 by leaf springs 22 and 23.
4 so as to be movable in parallel in the direction of arrow A. The tip of the vibration mechanism 7 is fixed to the holder 21,
The damper 72 is fixed at the resonance point, and the voice coil 7
3 is individually attached to the base end of the push rod 71, and a magnetic circuit 74 that applies a bias magnetic field to the voice coil 73.

In this case, the tape guides 2 and 3 not only define the running position of the magnetic tape 1 during recording, but also control the tape running due to the friction between the head surface and the tape when the magnetic head 4 is vibrated in a direction perpendicular to the tape track. Preventing instability. Further, the voice coil 73 is placed apart from the magnetic head 4 by the push rod 71 so as not to impart unnecessary noise to the magnetic head 4. Furthermore, the damper defines the reference position of the magnetic head 4,
At the same time, it also serves to suppress the resonance of the leaf spring.

FIG. 5 is a diagram showing another structure of the magnetic head drive section, in which the push rod 71 is connected to the holder 21.
Another feature is that another rod 75 is fixed in parallel, and both rods 71 and 75 are held by slide bearings 76 and 77 so that the magnetic head 4 can move in parallel. In this case, the leaf springs 22 and 23 in FIG. 4 are unnecessary, and the magnetic head 4
Accurate parallel movement can be achieved. The other parts are the same as in FIG. 4, but the damper 72 is supported by a case 78 of a magnetic circuit 74.

As described above, the present invention provides two tracks in which two tracking signals are recorded on one track in addition to a large number of tracks in which information signals are recorded, and tracks the tracking signals of each track on the same time axis. During playback, the difference between the playback signals from the two channels on each track is detected, and the difference signals from each track are added together.
Because it is less susceptible to dropouts and provides accurate track deviation signals,
This signal can be used to adjust the position of the tape with respect to the magnetic head. Therefore, high precision is not required for the tape guide or cassette leaf, tolerances on the tape width are not a problem, and the recording track can be adjusted even if it is meandering. Tracking is performed normally and stable playback output can be obtained even when the Therefore, the present invention is suitable for compact cassette PCM tape recorders and other magnetic tape recording and reproducing devices having multiple tracks.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a tracking device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram for detecting tracking deviation, Fig. 3 is an exploded perspective view of a drive section of a magnetic head, and Fig. 4 is an explanatory diagram It is a sectional view of another example of the same drive part. 1... Magnetic tape, 2, 3... Tape guide,
4...Magnetic head, 5...Error detection circuit, 6...
...Drive circuit, 7... Vibration mechanism.

Claims (1)

[Claims for Utility Model Registration] To reproduce the above information on a magnetic tape having a plurality of information tracks on which information signals such as music are recorded and at least two tracking tracks on which tracking signals are recorded. It includes an information reproducing magnetic head and a tracking signal reproducing magnetic head provided in the same number as the tracking tracks, which divides each tracking signal into two and reproduces them, and reproduces the reproduction of each tracking track on the same time axis. a group of reproducing magnetic heads; at least two amplifiers for detecting a difference between outputs of tracking signals divided and reproduced in each of the tracking signal reproducing magnetic heads; a summing amplifier for summing outputs from the amplifiers; A tracking device comprising: vibrating means for correcting track deviation by moving the reproducing magnetic head group in a direction perpendicular to the information track using an output.