JPH06101221B2 - Rotating head type magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type rotary head type magnetic recording / reproducing apparatus, and in particular, to a recording / reproducing azimuth head having a track width larger than a recording track width on a magnetic tape. The present invention relates to a rotary head type magnetic recording / reproducing apparatus for performing overwrite azimuth recording.

2. Description of the Related Art One of the problems that occurs in a helical scan rotary head type magnetic recording / reproducing apparatus is clogging of the rotary head.

As a means to detect that the rotary head is clogged during recording and normal recording is not performed, a monitor head is placed on the rotary cylinder in addition to the recording head as seen in a video tape recorder (VTR). There is a method of mounting and confirming the recording state by constantly reproducing the signal recorded on the magnetic tape.

A conventional rotary head type magnetic recording / reproducing apparatus as described above, particularly a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT) will be described below with reference to the drawings.

FIG. 6 is a block diagram of a conventional 4-head type R-DAT. 11A and 11B are recording azimuth heads, 12A and 12B are reproducing azimuth heads, 1 is an AD converter for converting an input analog signal into a PCM signal, and 2 is an encoder for encoding and modulating a PCM signal output from the AD converter 1. Modulation circuit 3, 3 is a selector, 4,5 is a recording amplifier that amplifies the output of the encoder and the modulation circuit 2 through the selector 3, and outputs it to the recording azimuth heads 11A and 11B, and 6 and 7 are from the reproduction azimuth heads 12A and 12B. A reproduction amplifier for amplifying the reproduction signal of, a selector 8, a decoder and demodulation circuit 9 for demodulating and decoding the output of the reproduction amplifier 6 or 7 via the selector 8, and a PCM output by the decoder and demodulation circuit 9.
A DA converter 13 for converting a signal into an analog signal is a magnetic tape.

A rotary head type magnetic recording / reproducing apparatus configured as described above,
The operation of the R-DAT will be described below. The input analog signal (voice, etc.) is converted to a PCM signal by the AD converter 1, error detection and correction codes are added by the encoder and modulation circuit 2, interleaved and 8-10 converted, and the rotary cylinder by the selector 3. Is alternately output to the recording amplifier 4 or 5. The recording signal amplified by the recording amplifier 4 or 5 is recorded on the magnetic tape by the recording azimuth head 11A or 11B.
Recorded on 13. The reproducing azimuth head 12A or 12B mounted on the rotating cylinder so as to scan this recording track with a time delay causes the reproducing amplifier 6 to sequentially reproduce reproduced signals.
Or output to 7. The selector 8 selects the reproduction amplifier 6 or 7 according to the rotation of the rotary cylinder, and the reproduction signal is subjected to 10-8 conversion and deinterleaving by the decoder and demodulation circuit 9 and corrected by error correction or interpolation. Is converted into an analog signal by.

In this way, by constantly monitoring the signal of the track recorded by the recording head with the reproducing head, an abnormality such as clogging during recording can be detected in real time.

However, since four heads are required in the above configuration, it is difficult to downsize the rotary cylinder and the rotary transformer for transmitting the recording / reproducing signal. Further, it also takes time and effort to adjust the mounting position of the head, and there is also a problem that the number of adjustment points of the tape running system increases.

In view of the above problems, the present invention provides a rotary head type magnetic recording / reproducing apparatus capable of detecting an abnormality such as clogging in real time during recording without increasing the number of heads.

Means for Solving the Problems In order to solve the above problems, according to the present invention, a track width wider than a recording trap pattern width on a magnetic tape is used in order to overwrite and record a part of a track immediately before recording. Forming a recording / reproducing azimuth head, a recording amplifier for outputting a recording signal to the recording / reproducing azimuth head, a reproducing amplifier for amplifying a reproducing signal from the recording / reproducing azimuth head, and a first recording track on the magnetic tape during recording. A signal generator for generating a pilot signal to be recorded in a predetermined area and a recording / reproducing azimuth head record the pilot signal while scanning the first predetermined area, and scan the second predetermined area. Is a timing command for controlling the reproduction of the crosstalk component of the pilot signal recorded in the adjacent first predetermined area of the immediately preceding track. The control circuit includes a control circuit and a detector that detects a reproduction signal of a crosstalk component to detect that recording is normally performed.

According to the above-described structure, the pilot signal is recorded in the first area on the track at the time of recording the PCM signal, and the azimuth head scans the second area adjacent to the first area on the next track. By reproducing the crosstalk component of the pilot signal in the first area, a recording abnormality due to clogging of the head can be detected in real time.

Embodiment A rotary head type magnetic recording / reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a rotary head type magnetic recording / reproducing apparatus, for example, an R-DAT in one embodiment of the present invention. First
In the figure, the same numbers are assigned to the components that perform the same operations as in the conventional example. 1 is AD converter (AD
C), 2 is an encoder and modulation circuit, 27 is a selector for selecting the input destination of the recording signal to either the encoder and modulation circuit 2 or the signal generator 22 described later, and is a control signal Sc from the timing control circuit 25 described later. Controlled by. 28 is a control signal from the timing control circuit 25
It is a selector that selects the output destination of the recording signal according to the rotation of the rotary cylinder by Sa. 4 and 5 are recording amplifiers,
Reference numerals 6 and 7 are reproduction amplifiers, 29 and 30 are selectors controlled by a control signal Sb from the timing control circuit 25, and input / output destinations of recording / reproduction azimuth heads 21A and 21B described later are set to the recording amplifiers 4 and 5 in the recording mode. , In the reproduction mode, the reproduction amplifiers 6 and 7 are selected. Reference numeral 31 is a selector for selecting an input destination of the reproduction signal according to the rotation of the rotary cylinder by a control signal Sa from the timing control circuit 25, and 32 is a decoder and demodulation circuit 9 to be described later or a band pass device to be described later. This is a selector that selects any one of 23 and is controlled by a control signal Sc from the timing control circuit 25. Reference numeral 9 is a decoder and demodulation circuit, and 10 is a DA converter. Reference numerals 21A and 21B denote recording / reproducing azimuth heads, which have different azimuths, and are attached to the rotary cylinder so as to face each other. A signal generator 22 generates a pilot signal for detecting a recording error, and outputs the pilot signal to the selector 27. twenty three
Is a band pass device that passes only the pilot signal of the reproduced signals from the recording and reproducing azimuth heads 21A and 21B, and 24 is a detector that detects the pilot signal of the output of the band pass device 23. Reference numeral 25 is a timing control circuit for controlling the selectors 27, 28, 29, 30, 31, 32.

FIG. 2 is a view showing an outline of winding the magnetic tape around the rotary cylinder in the present embodiment, 41 is a rotary cylinder, and 13 is a rotary cylinder.
Is a magnetic tape, 21A and 21B are recording and reproducing azimuth heads, and the winding angle is 90 ° + 2θ.

A rotary head type magnetic recording / reproducing apparatus configured as described above,
For example, the operation of the R-DAT will be described below.

When recording an analog input signal from the outside, the selectors 27 and 32 first select the terminal X and the selectors 28 and 31 select the terminal A according to the control signal of the timing control circuit 25.
The selectors 29 and 30 select the REC terminal, and the recording / reproducing azimuth head 21A transmits the PCM signal or the like that has passed through the AD converter 1, the encoder / modulation circuit 2 and the recording amplifier 4 to the magnetic tape 1.
Record on top of 3. When the rotary cylinder 41 rotates by a predetermined rotation angle (90 degrees in this case), the selectors 27 and 32 select the terminal Y and the magnetic tape 13 records the pilot signal output from the signal generator 22. Further, when the rotary cylinder 41 rotates by a predetermined angle θ, the selectors 29 and 30 select the PLAY terminal, and while the rotary cylinder 41 subsequently rotates by θ, the recording / reproducing azimuth head 21A enters the reproducing mode,
The reproduction signal is amplified by the reproduction amplifier 6 and output to the band pass device 23.

Figure 3 shows the state of the tracks on the magnetic tape.
I is the output of the encoder / modulation circuit 2 while the rotary cylinder 41 rotates 90 degrees after coming into contact with the magnetic tape 13.
A region in which signals and the like are recorded, II is a region in which a pilot signal which is the output of the signal generator 23 is recorded while rotating by θ thereafter, and III is a recording / reproducing azimuth head 21A in a reproducing state while rotating by θ thereafter. Area. L and l are the lengths of regions I, II and III. Rotating cylinder 41 from the beginning
When is rotated 180 degrees, the recording / reproducing azimuth head 21B starts recording on the magnetic tape 13, and the same operation is performed.

By the way, in the R-DAT, since the track width of the head (this is W _h ) is wider than the track width of the track actually recorded (this is T _p ), a part of the immediately preceding track (width [ W _h −T _p ]) is overwritten and recording is performed. Therefore, by setting l, that is, θ so that the region III currently scanned by the head overlaps the region II of the immediately preceding track, the recording / reproducing azimuth head 21A or 21B becomes the region II.
Area I of the last recorded track while scanning I
This will reproduce the crosstalk component of the I pilot signal. Figure 4 is a diagram showing the situation in detail, 21A, 21
B is a recording / reproducing azimuth head, and 42 is an edge of the magnetic tape 13.

Here, the condition of the above l is that the still angle of the recording track is θ.
_{If t} , Is. Therefore Becomes

Therefore, if θ and l are set to such values, the pilot signal recorded in the area II of the immediately preceding track is displayed in the band pass device 23 while the recording / reproducing azimuth head 21A or 21B is scanning the area III. The crosstalk component is amplified by the reproduction amplifier 6 or 7 and input. The band pass device 23 removes unnecessary components other than the pilot signal and outputs it to the detector 24. The detector 24 detects the presence or absence of the pilot signal, and if the pilot signal is detected, the recording is normally performed. If not detected, it is considered that an abnormality such as clogging of the head has occurred and an abnormality detection signal is output.

Fig. 5 shows the control signals when recording is done normally.
6 is a timing chart of a recording signal and a reproduction signal. Sa is a control signal for the selectors 28 and 31 (head switching signal), Sb is a control signal for the selectors 29 and 30 (recording / reproducing switching signal), Sc
Is a control signal (input / output destination switching signal) of the selectors 27 and 32, Sd is a recording signal, and Se is a crosstalk component reproduction signal of the pilot signal. These are the same as those shown in FIG. The selector function may be incorporated in each amplifier.

The pilot signal is a low-frequency single signal with low azimuth loss during crosstalk reproduction (for example, 130 kHz for R-DAT).
z sine wave) is suitable.

As described above, according to this embodiment, the actual recording track width T _p
In the rotary head type magnetic recording reproducing apparatus of helical scan type such as R-DAT for azimuth recording using two recording reproducing azimuth heads 21A and 21B wide track width W _h than the pilot signal in the region II at the time of recording Record the
While the recording / reproducing azimuth head 21A or 21B is scanning the area III, the crosstalk component of the pilot signal in the area II of the adjacent track is reproduced, and the detector 24 is detected through the reproducing amplifier 6 or 7 and the band pass device 23. By doing so, it is possible to confirm in real time whether or not the recording is normally performed.

Although the R-DAT has been described in this embodiment, any rotary head type magnetic recording / reproducing apparatus of the helical scan type for performing azimuth recording using an azimuth head wider than the actual recording track width may be used.

Further, although the regions II and III are set immediately after the region I, the arrangement of these three regions is such that the region II of one track and the region III of the other track of two adjacent tracks are always adjacent to each other. Any arrangement will do.

As described above, according to the present invention, a recording / reproducing azimuth head having a wider track width than the recording track pattern width on the magnetic tape for overwriting and recording a part of the immediately preceding track at the time of recording, A recording amplifier for outputting a recording signal to a recording / reproducing azimuth head, a reproducing amplifier for amplifying a reproducing signal from the recording / reproducing azimuth head, and a pilot signal to be recorded in a first predetermined area of a track on a magnetic tape during recording. And a recording / reproducing azimuth head scan the first predetermined area while recording the pilot signal, and while scanning the second predetermined area, the adjacent first track of the immediately preceding track. Timing control for controlling the recording amplifier and the reproducing amplifier so as to reproduce the crosstalk component of the pilot signal recorded in a predetermined area Equipped with a circuit and a detector that detects the normal recording by detecting the reproduced signal of the crosstalk component, it is possible to detect recording abnormalities such as head clogging in real time during recording. Moreover, there is no need to provide a special head for that purpose, and there is no concern about the size increase of the rotary cylinder.

[Brief description of drawings]

FIG. 1 is a block diagram of a rotary head type magnetic recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a schematic view of winding a magnetic tape around a rotary cylinder in this embodiment, and FIG. FIG. 4 is a recording track diagram on the magnetic tape, FIG. 4 is a detailed view of the relationship between the recording track and the head in this embodiment, and FIG. 5 is a control signal, a recording signal, and a reproduction signal of the rotary head type magnetic recording / reproducing apparatus in this embodiment. 6 is a block diagram of a conventional rotary head type magnetic recording / reproducing apparatus. 4,5 …… Recording amplifier, 6,7 …… Playback amplifier, 21A, 21B ……
Recording / playback azimuth head, 22 …… signal generator, 23 …… band pass device, 24 …… detector, 25 …… timing control circuit.

Claims (1)

[Claims] 1. A recording / reproducing azimuth head for forming a track width wider than a recording track pattern width on a magnetic tape for overwriting and recording a part of a track immediately before recording, and the recording / reproducing azimuth. A recording amplifier for outputting a recording signal to the head, a reproducing amplifier for increasing the reproduction signal from the pre-recording / re-azimuth head, and a pilot signal to be recorded in a first predetermined area of a track on the magnetic tape at the time of recording. And a recording / reproducing azimuth head for scanning the first predetermined area, the pilot signal is recorded through the recording amplifier, and a second predetermined area is scanned immediately before. A crosstalk component of the pilot signal recorded in the first predetermined area adjacent to the track is reproduced through the reproduction amplifier. A timing control circuit for controlling the recording amplifier and the reproduction amplifier, and a detector for detecting a reproduction signal of the crosstalk component to detect that recording is normally performed. Rotating head type magnetic recording / reproducing device.