JPH0485747A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To add a scramble function at a low cost by recording a phase servo signal indicating an azimuth state different from an actual one in the recording mode of a scramble mode. CONSTITUTION:The heads HA and HB are fixed at the positions opposite to a drum 1 by 180 deg. and have different azimuth angles, that is, these heads are set at A and B azimuth angles respectively. Then both heads HA and HB scan alternately a tape 2, i.e., a recording medium to perform the azimuth recording operations. When a scramble mode is selected for recording, a pilot signal generator 4 outputs a pilot signal of f2 or f4 at the H level of a switching pulse and a pilot signal of f1 or f3 at the L level of the switching pulse respectively. Thus the pilot signals of f2 and f4 are recorded at the A azimuth angle together with the pilot signals of f1 and f3 recorded at the B azimuth angle respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a recording/reproducing device with a scrambling function.

[Summary of the invention] The first invention performs azimuth recording using a plurality of heads,
In a recording/reproduction device that applies phase servo based on the recorded phase servo signal in the playback mode, when the scramble mode is selected, in the record mode, the phase servo signal indicating an azimuth state different from the actual azimuth state is recorded. When a recording medium recorded in scramble mode is played back, the servo is locked to the opposite azimuth, making it impossible to play back the video signal. Scrambling can be done at low cost simply by changing the phase servo signal to be recorded.

The second invention is a recording and reproducing apparatus that performs azimuth recording using a plurality of heads and applies phase servo based on the recorded phase servo signal in the reproducing mode, when the scramble mode is selected, the phase servo signal is changed in the reproducing mode. By applying phase servo to scan the head at an azimuth angle different from the azimuth state indicated by The servo is locked to scan with a head that has the same azimuth angle as the azimuth of the azimuth, and the video signal can be played back.

In the conventional scramble function, an encoder is provided in the recording circuit, and the encoder performs special signal processing different from normal signal processing on the video signal and records the signal. It is configured such that it can only be reproduced by an apparatus that has a special decoder in its reproduction circuit.

[Problem to be solved by the invention] However, in the above configuration, the encoder and/or
Also, since a decoder is required, the cost is high.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a recording and reproducing apparatus that can add a scrambling function at low cost and that can reproduce signals recorded using the scrambling function.

[Prior Art] Some VTRs (video tape recorders), which are recording and reproducing devices, are equipped with a scrambling function that performs recording processing so that normal devices cannot reproduce the data.

[Means for Solving the Problem 7] - A recording/reproducing device of the first invention for achieving the above object is provided with a plurality of heads having different azimuth angles, and scans the recording medium alternately with the plurality of heads. However, in the recording mode, the video signal is azimuthally recorded and a phase servo signal indicating the azimuth state is recorded, and in the playback mode, the phase servo is applied based on this phase servo signal.When the scramble mode is selected in the recording/playback device, the recording mode is switched on. Here, a phase servo signal indicating an azimuth state different from the actual azimuth state is recorded.

The recording/reproducing device of the second invention is provided with a plurality of heads having different azimuth angles, the plurality of heads alternately scan the recording medium, and in the recording mode, the video signal is recorded in the azimuth, and a phase servo control that indicates the azimuth state is provided. In a recording/reproducing device that records a signal and applies phase servo based on this phase servo signal in playback mode, when scramble mode is selected, in playback mode the head is scanned at an azimuth angle different from the azimuth state indicated by the phase servo signal. It has a phase servo applied to it.

[Function] According to the first invention, when the scramble mode is selected, the recording mode records a phase servo signal indicating an azimuth state different from the actual azimuth state, so when playing back with a normal device, the servo signal is moved to the opposite azimuth. is locked, making it impossible to reproduce the video signal, and all you have to do is change the phase servo signal to be recorded from the normal one.

According to the second invention, when the scramble mode is selected, in the reproduction mode, the azimuth state indicated by the phase servo signal is reversed, and the servo is locked to the same azimuth, making it possible to reproduce the video signal.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention, in which the present invention is applied to a VTR.

FIG. 1 shows a circuit block diagram during recording. In Figure 1, the bed H is placed 180° opposite the drum 1.
The heads A and Ha are fixed, and the heads HA and Hl have different azimuth angles, one head HA having an A azimuth angle and the other head HII having a B azimuth angle. These two spatulas 1-H^ and HB are configured to alternately scan a tape 2, which is a recording medium, to perform azimuth recording.

The switching pulse is H based on the rotational position of drum 1.
Switch between level and L level. That is, one head HA
is at H level during tape scanning, and is at L level while the other head H3 is scanning the tape, and this switching pulse is guided to microcomputer 3. The microcomputer 3 outputs a 2-bit signal of "00" to "11" to the pilot signal generator 4 based on the switching pulse. In the normal mode where the scramble mode signal is not input, the switching pulse is "00" or "10" when it is at H level.
” signal, and every time the level changes, ro
The output is switched in the order of "oJ-rolJ-rl, 0J-rll" and this is repeated. Further, in the scramble mode, when the switching pulse is an H1 novel, a signal of "01" or "11" is output, and the output is repeated in the above order every time the level is switched. The scramble mode is configured to be selectable using a scramble mode selection button (not shown). The pilot signal generator 4 outputs a pilot signal based on the input signal, f when the input signal is "00", f2 when the input signal is "roi" + f3 when the input signal is "rlO".
．． Outputs the pilot signal of rill's f4. Therefore, the relationship between the pilot signals recorded in the HETS HA, H, etc. is as shown in FIG. The pilot signal is a low frequency of 100 to 170 KHz without azimuth loss, and this pilot signal is passed through a low pass filter (LPF) 5.
t4 and is led to the adder 6. A video signal and an audio signal are led to this adder 6, where a pilot signal is added to these signals. The output of this adder 6 is selectively guided to each head HA, HB via a changeover switch SW. A switching pulse is guided to the changeover switch SW, and based on this switching pulse, the switch is switched to the FHA or HB side during tape scanning.

FIG. 2 shows a circuit block diagram during reproduction. In FIG. 2, the outputs of two heads I(A, I(B) are selectively led to a balanced modulation circuit 7 and a signal processing circuit via a changeover switch SW2. The balanced modulation circuit 7 has f1.
A reference pilot signal of ~f4 is input, and the reproduced pilot signal and the reference pilot signal are balanced-modulated. This output is sent to a 16 KHz band pass filter 8 and a 46 KHz band pass filter 9, respectively, and the outputs of both band pass filters 8 and 9 are input to an operational amplifier 10. The output of the operational amplifier 10 is sent to the adder 1 as phase error data.
1, where it is added to the speed error signal and sent to the drive circuit 12. The drive circuit 12 outputs a drive signal to a capstan motor (not shown) based on this error signal, so that the heads HA and HB are auto-tracking controlled. On the other hand, the switching pulse is set to the H level and L level based on the rotational position of the drum 1, as described above.
The levels are switched so that one head HA is at H level during tape scanning and the other head HB is at L level while tape scanning, and this switching pulse is guided to microcomputer 13. The microcomputer 13 outputs a 2-bit signal of "00" to "11" to the pilot signal generator 14 based on the switching pulse. In the normal mode where the scramble mode signal is not input, a signal of "00" or "10" is output when the switching pulse is at H level, and each time the level changes, "00" → "ON-rl"
The output is switched in the order of OJ - rl lj and this is repeated. Further, in the scramble mode, a signal of "01" or "11" is output when the switching pulse is at H level, and the output is repeated in the above order every time the level is switched. The scramble mode is configured to be selectable using a scramble mode selection button (not shown). The pilot signal generator 14 outputs a pilot signal based on the input signal, and when the input signal is "00", fl, rol
” when f2. When rlOJ, f3+ outputs f4 reference pilot signal when rllJ. This reference pilot signal is output to the balanced modulation circuit 7 via the low-pass filter 15.

In the above configuration, when the normal mode is selected and recorded, the pilot signal generator 4
In order to output f (or f3 pilot signal) at level and f2 (or f4) pilot signal at L level, f, at A azimuth as shown in Fig. 4(a).
or f3 pilot signal is f2 or f at B azimuth
4 pilot signals are recorded. When the tape recorded in the normal mode is played back in the normal mode, one head HA plays the track whose playback pilot signal is fl or f, as shown in FIG. 5(a).
Since the other head H scans the track 2 or f4, the track and heads HA and HB have the same azimuth, and the video signal and audio signal are reproduced.

Also, when the scramble mode is selected and recorded, the pilot signal generator 4 generates a pilot signal of f2 (or f4) at the H level of the switching pulse, and f, at the L level of the switching pulse.
In order to output pilot signals of (or f3), f2 and f4 at A azimuth as shown in Fig. 4(b).
The pilot signals of f and f3 are recorded at B azimuth. When the tape recorded in the scramble mode is played back in the normal mode, as shown in FIG. Since the other head H3 scans the track, the azimuths of the tracks and heads HA and Ha are reversed, and the video and audio signals are not reproduced.

Therefore, tapes recorded in scramble mode cannot be played back with normal equipment. When a tape recorded in scramble mode is played back in scramble mode, the fifth
As shown in figure (c), the regenerated pilot signal is f2 or f
4, one head HA selects f or f3
Since the other head H, scans a certain track, the track and the heads HA, HI1 have the same azimuth, and the video signal and the audio signal are reproduced.

Note that in this embodiment, there are two heads HA.

Although the case where the HBs are arranged at 180° opposing positions is shown, four heads may be arranged at 90° intervals and the heads facing each other may have the same azimuth, or it may have six or more heads. The present invention is also applicable to the following. Further, in this embodiment, a tracking pilot signal is used as the phase servo signal, but a control signal consisting of an H level and an L level may also be used. Further, in this embodiment, a scramble mode selection switch is provided to select whether or not to reproduce in scramble mode, but a determination circuit may be provided to automatically perform the determination. Furthermore, as long as azimuth recording is possible, the recording medium is not limited to tape, but may be a disk or the like.

[Effects of the Invention] As described above, according to the first invention, in a recording and reproducing apparatus that performs azimuth recording using a plurality of heads and applies phase servo based on the recorded phase servo signal in the reproducing mode, the scrambling mode When is selected, a phase servo signal indicating an azimuth state different from the actual azimuth state was recorded in the recording mode, so when playing back a recording medium recorded in scramble mode, the servo is locked to the opposite azimuth and the video signal is played back. For example, by modifying the microcomputer software and changing the phase servo signal to be recorded, it is possible to perform scrambling at low cost.

Further, according to the second invention, in the recording and reproducing apparatus that performs azimuth recording using a plurality of heads and applies phase servo in the reproduction mode based on the recorded phase servo signal,
When the scramble mode is selected, in the playback mode, the phase servo signal is configured to apply the phase servo to scan the head at an azimuth angle different from the azimuth state indicated by the phase servo signal. When a recording medium on which a signal has been recorded is reproduced in scramble mode, the servo is locked so that scanning is performed with a head having the same azimuth angle as the azimuth of the recording medium, making it possible to reproduce the video signal.

Furthermore, when scrambling is performed using an encoder as in the past, it is common to scramble only the video signal and record the audio signal as is, which increases the cost even more when the audio signal is also scrambled. According to the present invention, both the video signal and the audio signal can be scrambled at low cost.

[Brief explanation of the drawing]

1 to 5(c) show an embodiment of the present invention, FIG. 1 is a circuit block diagram during recording, FIG. 2 is a circuit block diagram during reproduction, FIG. 3 is a time chart diagram, Figure 4(a)
is the recording format diagram of normal mode, Figure 4(b)
is the scramble mode recording format diagram, Figure 5 (
Figure 5(b) is a head scanning state diagram of normal mode during playback, and Figure 5(c) is a head scanning state diagram of scramble mode during playback. It is. HA, HE...head, 2...tape (recording medium)
. Quim + Yard Map Figure 3

Claims (2)

[Claims] (1) A plurality of heads with different azimuth angles are provided, and the plurality of heads alternately scan the recording medium. In the recording mode, the video signal is recorded azimuthally, and a phase servo signal indicating the azimuth state is recorded, and in the playback mode Now, in a recording and reproducing apparatus that applies phase servo based on this phase servo signal, when a scramble mode is selected, in the recording mode, a phase servo signal indicating an azimuth state different from the actual azimuth state is recorded. Device. (2) A plurality of heads with different azimuth angles are provided, and the plurality of heads alternately scan the recording medium. In the recording mode, the video signal is recorded azimuthally, and a phase servo signal indicating the azimuth state is recorded, and in the playback mode Now, in a recording/reproduction device that applies phase servo based on this phase servo signal, when scramble mode is selected, in reproduction mode, phase servo is applied so that the head is scanned at an azimuth angle different from the azimuth state indicated by the phase servo signal. A recording/playback device characterized by: