JP2718217B2 - Magnetic recording / reproducing device - Google Patents

Description

The present invention relates to a helical scan type magnetic recording such as a video tape recorder configured to record and reproduce information such as a video signal and an audio signal on a magnetic tape. It relates to a playback device.

[Prior Art] FIG. 6 shows an arrangement of magnetic heads in a conventional magnetic recording / reproducing apparatus disclosed in, for example, JP-A-61-165801, and FIG. FIG. 3 is a diagram showing a recording track pattern.

In FIG. 6, (1) is a rotating drum, (2a), (2)
b) is a set of first magnetic heads that are 180 degrees apart from each other, (3a) and (3b) are 180 degrees apart from each other, and the first magnetic heads (2a) and (2b) are Is a set of second magnetic heads spaced 90 degrees from each other.

In FIG. 7, (4) is a magnetic tape, which runs in the direction of the arrow (R) in FIG. (5) is the first magnetic head (2
The track recorded by a), (6) is the track recorded by the second magnetic head (3a), (7) is the track recorded by the first magnetic head (2b), and (8) is the second The tracks recorded by the magnetic head (3b) of FIG.
Make up the frame.

FIG. 8 is a block diagram showing a configuration of a recording signal processing system in the case where two channels of video signals are simultaneously digitally recorded with the arrangement of the magnetic heads and the track pattern as shown in FIGS. 6 and 7. , (9a) is a first low-pass filter (hereinafter, referred to as a first LPF) for band-limiting to sample the first video signal, and (9b) is a second low-pass filter.
A second LPF that limits the bandwidth of the video signal, (10a) is a first A / D converter that samples the first video signal, and (10b) is a second A / D converter that samples the second video signal It is.

(11a) is a first encoder for adding an error correction code or the like to the digital data from the first A / D converter (10a) and encoding the digital data, and (11b) is a first encoder for encoding the digital data from the second A / D converter (10b). A second encoder for similarly encoding digital data, (12a) is a first memory used for encoding in the first encoder (11a), (12a)
b) is a second memory used for encoding in the second encoder (11b), and (13a) is a recording code optimal for magnetic recording and reproduction of digital data encoded in the first encoder (11a). The first converter for recording and encoding as described above, (13b) is a second modulator for recording and encoding the digital data encoded by the second encoder (11b).

(14a) is a first recording head amplifier for driving the output of the first modulator (13a) to the first magnetic heads (2a) and (2b), and (14b) is the second modulator (13b) Is a second recording head amplifier for driving the output of the second magnetic head to the second magnetic heads (3a) and (3b).

FIG. 9 is a diagram showing the distribution of the magnetic heads of the first and second channel recording data and the recording period of the magnetic head. Each channel data is output from the first modulator (13a) and the second modulator (13b). Show data.

 Next, the operation of the above configuration will be described.

By running the magnetic tape (4) at normal double speed,
Video signals are recorded and reproduced by first magnetic heads (2a) and (2b) arranged at an interval of 180 degrees from each other on a rotating drum (1), and second magnetic heads (3a) and (2a). The audio signal or other video signal is recorded and reproduced according to 3b).

In this case, the first and second magnetic heads (2a), (2
As shown in FIG. 7, the recording track pattern on the magnetic tape (4) according to (b) and (3a) and (3b) is track (2a) by one of the first magnetic heads (2a) and (2b). 5)
Is recorded, and the track (6) is recorded by one of the second magnetic heads (3a) and (3b) (3a). Similarly, the first and second magnetic heads (2a), (2b) and (3
Tracks (7) and (8) are recorded by the other of (a) and (3b) (2b) and (3b).

Therefore, two pieces of information are recorded by one rotation of the rotating drum (1).

Here, the operation of the recording signal processing system will be described by taking as an example the case where two-channel video signals are simultaneously digitally recorded. However, although the audio signal processing system is not shown here, it is digitally recorded in the same manner as the video signal.

In FIG. 8, the video signals of the first and second channels are band-limited by the first LPF (9a) and the second LPF (9b) so as to pass the video signal band, and then the first A / D converter (10a ) And the second A / D converter (10b) to sample at more than twice the video signal band.

Taking the general NTSC system as an example, the video signal bandwidth is about 4.
It is 5 MHz, and it is necessary to sample at a frequency of 9 MHz or more in view of Nyquist's theorem. The color signal is 3.58MHz
In general, the sampling frequency is set to an integral multiple of 3.58 MHz in consideration of beat interference with the sampling frequency, for example, since the signal is transmitted by quadrature two-phase modulation on the carrier.

From the above explanation, the sampling frequency is 3 · fs
c, that is, about 10.7 MHz or 4 · fsc, that is, about 14.3 MHz in many cases.

The recorded video data digitized as described above is respectively supplied to a first encoder (11a) and a second encoder (11a).
According to b), encoding is performed so that errors occurring during magnetic recording and reproduction can be corrected. The encoding here is performed in the first memory (12
a) and the second memory (12b).

Next, the encoded digital data is recorded and encoded by a first modulator (13a) and a second modulator (13b) by, for example, a system such as NRZ and NRZI so that the data becomes optimal for magnetic recording and reproduction. You.

Subsequently, the modulated recording video data is supplied to the first recording head amplifier (14a) and the second recording head amplifier (14a).
Via b), the digital data of the first channel is provided by the first magnetic heads (2a) and (2b), and the digital data of the second channel is provided by the second magnetic heads (3a) and (2a).
Recorded according to (3b).

Here, as shown in FIG. 9, the magnetic head distribution of the recording data of two channels is such that DATA1-1 of the first channel is recorded on the track (5) by the first magnetic head (2a),
DATA1-2 of the first channel is the first magnetic head (2
b) is recorded on track (7). Similarly, for the second channel, DATA2-1 is recorded on the track (6) by the second magnetic head (3a), and DATA2-2 is recorded on the second magnetic head (3a).
b) is recorded on track (8).

With the above operation, two-channel video signals can be recorded simultaneously, and at the time of reproduction, similarly, by tracing tracks, two-channel video signals can be reproduced simultaneously.

[Problems to be Solved by the Invention] Since the conventional magnetic recording / reproducing apparatus is configured as described above, it is necessary to add two magnetic heads to record a two-channel video signal. Thus, a signal processing circuit for two channels is required, and an operation of recording on one channel and reproducing on the other channel cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to record data on one channel and reproduce data on the other channel without adding a magnetic head and without increasing the circuit scale. It is an object of the present invention to provide a magnetic recording / reproducing device capable of realizing an operation.

[Means for Solving the Problems] A magnetic recording / reproducing apparatus according to the present invention is characterized in that it is configured to scan 2 × N or more tracks in one cycle of information.

[Operation] According to the present invention, the number of scans (the number of tracks) on the magnetic tape can be increased by rotating the rotary drum twice or more within one cycle of information. An operation of reproducing one channel while recording the other channel can be performed.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an arrangement of a magnetic head in a magnetic recording and reproducing apparatus according to an embodiment of the present invention, and FIG. 2 shows a recording track pattern on a magnetic tape by the magnetic head.

In FIG. 1, (1) is a rotating drum, and (2a) is a rotating drum.
The magnetic head (2b) is a second magnetic head, and these two heads (2a) and (2b) are spaced from each other by 180 degrees.

In FIG. 2, (15) is a track on which the first magnetic head (2a) scans on the magnetic tape (4) during the first rotation of the rotary drum (1), and (16) is a track on the rotary drum (1). The track scanned by the second magnetic head (2b) on the rotation, (17)
Is the first magnetic head (2) at the second rotation of the rotating drum (1).
a) is a track to be scanned, and (18) is a track to be scanned by the second magnetic head (2b) during the second rotation of the rotary drum (1).

FIG. 3 is a block diagram showing the configuration of a signal processing system in a case where a two-channel video signal is reproduced while simultaneously digitally recording a two-channel video signal using the magnetic head and the track pattern as shown in FIGS. 1 and 2. In the figure, (9)
(14) to (14) correspond to (9a) to (14) of the conventional example shown in FIG.
Since they are the same as a), their detailed description is omitted.

In FIG. 3, (19) is a reproducing head amplifier for amplifying the reproducing signals from the magnetic heads (2a) and (2b),
(20) is a demodulator that performs recording and encoding in the reverse manner to recording and encoding in the modulator (13), and (21) performs error correction and detection by decoding for error correction encoding in the encoder (11). Decoder (22), a memory used for decoding by the decoder (21), (23) a D / A converter that converts error-corrected reproduced video data into analog data, and (24) a reproduced video signal LPF that is limited by the signal band.

(25) a head changeover switch for switching a signal from the recording head amplifier (14) during recording and a reproduction signal from the magnetic heads (2a) and (2b) during reproduction based on the head changeover signal (26); 27) is a first channel video signal input terminal, (28) is a first channel video signal output terminal, (29) is a second channel video signal input terminal,
(30) is the output terminal of the video signal of the second channel, (31)
Is a video signal changeover switch for switching input / output signals of the first and second channels based on a video signal changeover signal (32).

FIGS. 4A and 4B are diagrams showing the recording and reproduction switching state of the first and second magnetic heads (2a) and (2b) by the head switching signal (26). )
Record at high level (W) and play at low level (R)
I do. The hatched portion of each of the magnetic heads (2a) and (2b) indicates a magnetic tape trace period.

FIG. 5 is a diagram showing the recording / reproducing data and the magnetic head scanning state when reproducing the video signal of the second channel while recording the video signal of the first channel. ) Is recording data obtained by digitizing the video signal of the first channel, (34) is recording compression data obtained by time-compressing the recording data (33), and (35) is second recording data.
Playback compressed data obtained by playing back channel data, (36)
Is reproduction data obtained by time-expanding the reproduction compression data (35). The hatched portion of each of the magnetic heads (2a) and (2b) indicates a magnetic tape trace period.

 Next, the operation of the above configuration will be described.

In FIG. 1, a rotating drum (1) on which a pair of magnetic heads (2a) and (2b) at 180-degree intervals are mounted is rotated twice as much as the conventional one, and a magnetic tape (4) is rotated. When the tape is fed at twice the speed as in the conventional case, the track on the magnetic tape (4) rotates twice within the time required for one rotation of the conventional rotating drum as shown in FIG. In the first rotation, the track (15) is scanned by the first magnetic head (2a), and the track (16) is scanned by the second magnetic head (2b).

In the next one rotation, the track (17) is scanned by the first magnetic head (2a), and the track (18) is scanned by the second magnetic head (2b). In the above four tracks, track (15) and track (17) are used as one channel, and track (16) and track (18) are used as the other channel, and one channel is recorded and the other channel is reproduced. The operation performed will be described with reference to FIG.

First, in the recording signal processing system, the video signal switching signal (32)
The video signal changeover switch (31) is operated in response to the input of the input signal, and the input terminal (27) of the video signal of the first channel or the input terminal (29) of the video signal of the second channel is selected. The signal is input to the LPF (9).

The input video signal is, as in the case of the conventional example,
A / D converter (10) after band limitation by LPF (9)
Is digitized. In the next encoding, the encoder (11) stores the data in the memory (12) in the same manner as in the conventional example.
, And are recorded and coded by the modulator (13) so as to be recordable on the magnetic tape (4), and are transmitted to the first magnetic head (2) via the head changeover switch (25).
a) Or the recording is performed by the second magnetic head (2b).

In the reproduction signal processing system, the first magnetic head (2a)
Alternatively, the reproduction signal reproduced by the second magnetic head (2b) is supplied to the demodulator (20) via the head changeover switch (25).
Are recorded and decoded, and error correction, detection and correction are performed by the decoder (21) using the memory (22).

Next, the reproduced video signal analogized by the D / A converter (23) is band-limited by the LPF (24), and the video signal changeover switch (31) is operated by the video signal changeover signal (32). The video signal output terminal (28) of the channel or the output terminal (30) of the video signal of the second channel is transmitted.

Here, the head changeover switch (25) responds to a head changeover signal (26) as shown in FIG. 4 by a recording signal or a reproduction signal to the first magnetic head (2a) and the second magnetic head (2b). Are switched, and a recording signal is selected at a high level of the head switching signal (26), and a reproduction signal is selected at a low level of the head switching signal (26).

FIG. 4 (A) shows that the first channel is recorded by the first magnetic head (2a) and the second channel is recorded by the second magnetic head (2b).
FIG. 4 (B) is switched so that the first magnetic head (2a) reproduces the first channel and the second magnetic head (2b) records the second channel.

In FIG. 5, a case where the video signal of the second channel is reproduced while simultaneously recording the video signal of the first channel will be described. The video signal of the first channel is converted by the A / D converter (10). The digitized data is divided into blocks, for example, in units of fields, and the recording data (33) (W-DATA1, W-DATA2,...) In FIG.
Becomes

The recording data (33) is error-correction-coded by the encoder (11) and time-compressed at the same time as the recording compression data (34) (WD0, WD1, DWD2,...) In FIG. .

Next, the recorded compressed data (34) is shown in FIG.
The first magnetic head (2a) is a magnetic tape (4)
2 is switched to the recording head amplifier (14) by the head switching signal (26) while scanning the track (15) in FIG.
And track (17).

On the other hand, while the second magnetic head (2b) scans the magnetic tape (4), it is switched to the reproducing head amplifier (19) by the head switching signal (26), and the video signal of the second channel in FIG. Play the recorded track (16) and track (18). This reproduced signal is reproduced in a time-compressed state at the time of recording, and the reproduced compressed data (3
5) (RD1, RD2, ...).

Next, the reproduced compressed data (35) is subjected to error correction decoding by the decoder (21) and time-expanded at the same time, and the reproduced data (36) divided into fields in FIG.
(R-DATA0, R-DATA1,...). The reproduced data (36) is converted into an analog signal by the D / A converter (23) and reproduced and output as a second channel video signal.

As described above, the rotating drum (1) is rotated twice during one frame period of the video signal, and one channel is scanned by the magnetic head (2a) or (2b) twice on the magnetic tape (4). Data of one frame of the video signal of
Recording is performed with time compression for each field, and at the same time, the other magnetic head (2b) or (2a)
In the scanning period, the video signal of the other channel is reproduced one field at a time, and data is extended for one frame to reproduce one frame of data, so that one channel can be recorded and the other channel can be reproduced. .

In the above embodiment, regarding the channel configuration on the magnetic tape (4), the track (15) and the track (17) are used as one channel, and the track (16) and the track (1) are used.
8) The other channel is described above, but the channel configuration is such that track (15) and track (16) are one channel, and track (17) and track (18) are the other channel. In this case, the same effect as in the above embodiment can be obtained.

Further, in the above-described embodiment, the case where one cycle of information is one frame and recording is performed on two tracks for one cycle of information has been described. However, one cycle of information may be one field and may be an integral multiple of one field and one frame. It may be. Further, the number of tracks to be recorded / reproduced per information cycle may be any number.

[Effects of the Invention] As described above, according to the present invention, by rotating the rotating drum twice or more within one cycle of information,
The number of tracks to be scanned within the same period is increased, and recording / reproduction is performed in a time-division manner.
The operation of reproducing the other channel while recording the other channel becomes possible, so that there is little change from the one-channel recording / reproducing apparatus and it can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is a layout diagram of a magnetic head in a magnetic recording and reproducing apparatus according to one embodiment of the present invention, FIG. 2 is a diagram showing a recording track pattern, FIG. 3 is a block diagram showing a configuration of a signal processing system in the present invention, FIG. 4 is a diagram showing a recording / reproducing switching state of each magnetic head by a head switching signal, FIG. 5 is a diagram showing recording / reproducing data and a scanning state of the magnetic head, and FIG. layout drawing,
FIG. 7 is a diagram showing a recording track pattern on a magnetic tape, FIG. 8 is a block diagram showing a configuration of a recording signal processing system in a conventional magnetic recording / reproducing device, and FIG. 9 is a diagram showing recording data distribution in a conventional device. FIG. (1) ... rotating drum, (2a) ... first magnetic head,
(2b)… second magnetic head, (4)… magnetic tape. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. Two magnetic heads for recording and reproducing information on a magnetic tape, wherein the two magnetic heads are mounted, and one magnetic head scans the magnetic tape for two or more tracks during one cycle of the information. A rotating drum that rotates at a speed as high as possible, a head that supplies a signal for recording information on one of the two magnetic heads and reproducing information on the other, and switches the signal within the one cycle period A magnetic recording / reproducing apparatus comprising a changeover switch.