JPH0559517B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a helical scan magnetic field that records and reproduces information on inclined tracks on a magnetic tape wound at a predetermined angle around a rotating drum having at least two rotating magnetic heads. The present invention relates to a recording/reproducing device.

[Summary of the invention]

The present invention is a helical scan magnetic recording/reproducing device in which a magnetic tape is transported at high speed while being wound around a rotating drum, the envelope of an RF signal is detected from the reproduction signal of a rotating magnetic head, and the envelope corresponding to the number of tracks is detected. Count the number of changes in the level, obtain information about the transfer amount of the magnetic tape from the counted value, compare the obtained transfer amount information with a preset transfer amount setting value, and if the comparison value is zero. When this happens, the transfer of the magnetic tape is stopped.

[Conventional technology]

In a helical scan magnetic recording and reproducing device, such as a video tape recorder, in order to search for a desired program from multiple recorded programs, a system that corresponds to the non-information portion (between songs) between each program is used. An index signal and cue signal for cueing are recorded at the position. Such signals are generally recorded and reproduced by a fixed magnetic head on a cue track parallel to the running direction of the magnetic tape.

[Problem that the invention seeks to solve]

However, such a conventional device has the disadvantage that a fixed magnetic head, a generator for a queue signal, an index signal, etc. are specially required, making the device complicated and expensive. Furthermore, it is only possible to search for a position where a cue signal has been recorded in advance, and it is not possible to search for an arbitrary position in the middle of a program.

As a solution to this drawback, there is a method in which, for example, an address signal is recorded at a predetermined position on a track that records a video signal tilted with respect to the running direction of the magnetic tape, and the predetermined position is searched by reading out this address signal. be. However, in this method, since it is necessary to read the address signal, the magnetic tape cannot be transferred at high speeds such as rewinding or fast forwarding, and the retrieval process takes a long time.

[Means for solving problems]

FIG. 1 shows the present invention in an R-DAT (Rotary head Digital Audio
This is a block diagram of an application of Taperecorder. In the figure, reference numeral 1 denotes a rotating drum, which has two rotating magnetic heads A and B that are spaced apart from each other by 180 degrees and have different azimuths (for example, ±20 degrees). A magnetic tape 2 is wound around the rotating drum 1 at, for example, 90 degrees. Reels 3 and 4 take up or supply the magnetic tape 2.
A reel motor 5 rotates the reel 3 or 4 via an idler 6. Reference numeral 7 denotes an equalizer amplifier circuit, which equalizes and amplifies the reproduced signals output from the rotating magnetic heads A and B. 8 is a detection circuit that detects the envelope of the RA signal output from the amplifier circuit 7. 9 is a counter that counts the output of the detection circuit 8, and 10 is an arithmetic circuit that calculates the output of the counter 9. A comparison circuit 11 compares the output of the arithmetic circuit 10 and the output from the setting circuit 12. 13 is a drive circuit;
The reel motor 5 is driven via a switch 14.

[Effect]

The effect will now be explained. When recording digital audio signals, the rotating drum 1 is rotated at a speed of, for example, 2000 rpm by a motor (not shown), and the magnetic tape 2 is rotated at a speed of, for example, 7.2 (or 9.0) mm/s by a capstan and a pinch roller (not shown).
is run at a speed of The rotating magnetic heads A and B are switched alternately, and a second magnetic head is placed on the magnetic tape 2.
As shown in the figure, the running direction (rightward in the figure)
A track is formed that is inclined at a predetermined angle with respect to the track, and a digital audio signal is recorded there.

On the other hand, during a search, when the user specifies a position to be searched, the setting circuit 12 outputs a signal corresponding to the specified position to the comparison circuit 11. The comparison circuit 11 controls the switch 14 in response to the error signal between the signal from the arithmetic circuit 10 and the signal from the setting circuit 12, and closes the switch 14.
As a result, the motor 5 is driven by the drive circuit 13, and the reel 3 or 4 is driven in accordance with the direction of the designated position.
is rotated via an idler 6. Therefore, the magnetic tape 2 is fast-forwarded or rewound while being wound around the rotating drum 1 at 90 degrees. The speed of the magnetic tape 2 during fast forwarding or rewinding is n when recording and reproducing.
If it is multiplied (for example, 200 times), the rotating magnetic head A,
B crosses n/2 tracks (only two tracks are shown for convenience in the figure) in one trace. Since the magnetic tape 2 is wound only 90 degrees around the rotating drum 1, after one rotating magnetic head A (B) traces n/2 tracks, during the next 90 degree rotation, The next n/2 tracks will not be traced by any of the rotating magnetic heads, and during the next 90 degree rotation, rotating magnetic head B(A) will trace n/2 tracks, and the next During the 90 degree rotation of the next n/
The two tracks are not traced by any of the rotating magnetic heads and the same operation is repeated. Furthermore, among the n/2 tracks traced by the rotating magnetic head A (B), only every other n/4 track has the same azimuth. Therefore, rotating magnetic heads A and B
The RF signal output from the RF signal is as shown in FIG. In other words, every time the rotating drum 1 rotates 90 degrees,
Parts where the RF signal appears and parts where it does not appear alternately. In the area where the RF signal appears, the level reaches a peak every other track.

After the RF signal is amplified by the equalizer amplifier circuit 7, its envelope is detected by the detection circuit 8. The envelope is sliced at a predetermined level, and for example, the number of level changes (the number of peaks) above the predetermined level is counted by the counter 9.
It is counted by Since the count value of the counter 9 is 1/4 of the number of tracks passed by the magnetic tape 2, the value is multiplied by 4 by the arithmetic circuit 10 and converted into a value corresponding to the running distance. When this converted value becomes equal to the value set by the setting circuit 12, the comparison circuit 11 opens the switch 14. Therefore, at that time, the running of the magnetic tape 2 is stopped and the designated position is detected. The operation after the designated position is detected depends on the operation command, but for example, a normal reproduction operation is started from that position.

Note that the signal input to the comparator circuit 11 may not be a signal representing the number of tracks, but may be a signal representing, for example, recording/reproducing time. Rotating drum 1
If it rotates at 2000 rpm, the time required for one rotation is 30 ms, and since two tracks are formed in one rotation, the recording/reproducing time for one track is 15 ms. Therefore, in this case, for example, the arithmetic circuit 10 sets the count value N of the counter 9 to the value 0.06 (=
4×0.015). Of course, in such a case, the signal from the setting circuit 12 is also converted into a signal corresponding to time and input to the comparison circuit 11.

For example, a predetermined position can be finely searched by a conventional search using an index signal, queue signal, address signal, etc., and the present invention can be used as a rough search in the previous stage, thereby combining the conventional search method of the present invention. They can also be used together.

〔effect〕

As described above, in the present invention, a magnetic tape is transported at high speed while being wound around a rotating drum,
The envelope of the RF signal is detected from the reproduction signal of the rotating magnetic head, the number of changes in the level of the envelope corresponding to the number of tracks is counted, and information regarding the transport amount of the magnetic tape is obtained from the counted value. The transfer amount information set in advance is compared with a preset transfer amount setting value, and the transfer control of the magnetic tape is performed based on the comparison value. The structure is simple, the magnetic tape can be run at high speed, and the time required for the search can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram when the present invention is applied to an R-DAT, FIG. 2 is a schematic plan view of its track pattern, and FIG. 3 is a waveform diagram of its RF signal. 1... Rotating drum, 2... Magnetic tape, 3, 4
... Reel, 5 ... Reel motor, 6 ... Idler, 8 ... Detection circuit, 9 ... Counter, 10 ...
Arithmetic circuit, 11... Comparison circuit, 12... Setting circuit, 14... Switch.

Claims (1)

[Scope of Claims] 1. A helical scan magnetic recording and reproducing device for reproducing information recorded on an inclined track on a magnetic tape wound at a predetermined angle around a rotating drum having at least two rotating magnetic heads with different azimuths, The magnetic tape is transported at high speed while wound around the rotating drum, the envelope of the RF signal is detected from the reproduction signal of the rotating magnetic head, and the number of changes in the level of the envelope corresponding to the number of tracks is calculated. counting, obtaining information regarding the transfer amount of the magnetic tape from the counted value, comparing the obtained transfer amount information with a preset transfer amount setting value, and controlling the transfer of the magnetic tape based on the comparison. What is claimed is a helical scan magnetic recording and reproducing device.