JP3163584B2 - Playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus, and more particularly to a reproducing apparatus.
Is related to the process of generating a clock phase-synchronized with the playback signal.
You.

[0002]

2. Description of the Related Art As a conventional recording and reproducing apparatus of this kind,
Multi-channel recording type video tape recorder (VT
R). Multi-channel recording type VT that divides a Hi-Vision signal into two channels and records it by FM modulation
In the case of R, for example, first, when a VTR reproduces a signal including video information (hereinafter referred to as a video information signal) and converts it into a video signal, the reproduced video information is converted into an A / D signal.
It is configured to perform digital processing after conversion, D / A conversion and output.

A processing unit for performing this digital processing is usually
It has a memory for one to two frames and converts video information signals of two channels into video signals of Y, PB, PR signals or G, B, R signals. In the reproduction system of the digital processing unit, a clock synchronized with a synchronization signal included in the reproduced video information signal is used as a sampling clock of the A / D converter and an input clock of the memory, and an output clock of the memory and a D / D converter are used. By using a clock synchronized with the line as the clock of the A converter, the time axis correction for removing the jitter of the reproduced signal is performed.

[0006] A PLL (Phase Locked Loop) circuit which is locked to a horizontal synchronizing signal or a synchronizing signal such as a burst included in the reproduced video information signal is used as a phase synchronizing control circuit. A sampling clock for the / D converter is generated. The loop filter of the PLL circuit is designed so as to follow the tape jitter at the time of reproduction and to reduce the steady-state phase error.

[0005]

However, in the above-mentioned conventional recording / reproducing apparatus, the relative speed between the head and the tape greatly changes in the case of a high-speed search, so that the PLL circuit can follow the tape jitter during reproduction. There is a problem that it becomes impossible. For example, in the case of a high-speed search of ± 30 times speed, the change in relative speed between the head and the tape is ± 15%.
About. It is difficult to set the lock range of each PLL circuit so as to cover the change in the relative speed and satisfy characteristics such as a steady phase error required during normal reproduction. The signal is disturbed in the time axis direction, making it impossible to identify the reproduced video.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a recording / reproducing apparatus capable of reproducing an image well even in a high-speed search.

[0007]

Reproducing apparatus according to claim 1 of the present invention to achieve SUMMARY OF for the] upper Symbol purpose, of a plurality of channels by a plurality of rotary heads from the tape-shaped recording medium in which a number of helical tracks are formed Reproducing means for reproducing signals in parallel, a plurality of PLL circuits each having a different lock range and generating a clock phase-synchronized with the reproduced signals of the plurality of channels, and a clock generated by the plurality of PLL circuits. Processing means for processing the reproduced signal by using the processing means. Claim 2
Reproducing apparatus according to the a feature in that it has a locking range corresponding to the tape transport has a speed different special playback mode, each of the plurality of PLL circuits, reproduction signal frequency of the plurality of special playback mode to each other I do.
Further, a reproducing apparatus according to a third aspect of the present invention has a reproducing means for reproducing signals of a plurality of channels in parallel from a tape-shaped recording medium having a plurality of helical tracks formed thereon by a plurality of rotary heads, and a first lock range. A first PLL circuit for generating a clock phase-synchronized with a reproduction signal of a first channel among the plurality of channels, and a second lock range different from the first lock range. A second PLL circuit for generating a clock phase-synchronized with the reproduction signal of the second channel;
Processing means for processing the reproduction signals of the plurality of channels using clocks generated by an L circuit and a second PLL circuit, wherein the tape-shaped recording medium is transported at a first speed, and the processing means A first special playback mode for processing a playback signal of the first channel using a clock generated by the first PLL circuit, and a second special playback mode in which the tape-shaped recording medium has a second speed different from the first speed. And a second special reproduction mode in which the processing means processes the reproduction signal of the second channel using a clock generated by the second PLL circuit.

[0008]

According to the present invention, a large number of helical tracks are formed.
From multiple tape heads
When reproducing signals of a plurality of channels in parallel, the reproduced signals are processed using clocks generated by a plurality of PLL circuits having different lock ranges , so that the signals are stable even in a reproduced mode in which the reproduced signal frequency is different. Thus, a reproduced signal can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a recording / reproducing apparatus according to the present invention, FIG. 2 is a waveform diagram showing a TCI signal in the recording / reproducing apparatus of FIG. 1, and FIG. Explanatory diagram showing a tape pattern in the apparatus, FIG.
Is an explanatory diagram showing a lock range of the PLL circuit of the reproducing system in FIG. 1, and FIG. 5 is an explanatory diagram showing an operation of the head at the time of special reproduction.

FIG. 1 shows a VTR of a multi-channel recording system in which a Hi-Vision signal is divided into two channels A and B and recorded by FM modulation as an embodiment. The upper part shows a recording system, and the lower part shows a reproducing system. Input Hi-Vision signal Y, P
B and PR are A / D converters 101a to 101c, respectively.
Is converted into a digital signal, and the digitized Hi-Vision signals Y, PB, PR are converted to TCI (Time
Compressed Integration) encoder 102
As shown in FIG. 2, the luminance signal Y and the chrominance signal C are converted into TCI signals of two channels A and B multiplexed on a time axis.

Next, the TCI signals of the channels A and B are converted into analog signals by D / A converters 103a and 103b, respectively, and are converted into FM signals by the FM modulation circuits 104a and 104b.
b, and the recording amplifiers 105a and 105b
After being amplified by the magnetic tape 10a, the recording heads 106a and 106b form a magnetic tape 10 in a tape pattern as shown in FIG.
9 recorded.

Here, in this recording system, the sync separation circuit 107 extracts a horizontal sync signal and a vertical sync signal from the luminance signal Y or sync signal SYNCin of the input Hi-Vision signal, and the PLL circuit 108 A / D converters 101a to 101c and TCI
A master clock for the encoder 102 and the D / A converters 103a and 103b is generated.

The video information signals of channels A and B recorded on the magnetic tape 109 are reproduced into RF signals by the reproducing heads 110a and 110b, respectively, amplified by the reproducing amplifiers 111a and 111b, and then amplified by the FM demodulation circuit. The signals are FM-demodulated by 112a and 112b and converted into TCI signals as shown in FIG.
a and 113b are converted into digital signals. The TCI signal converted into the digital signal is restored to a high-definition signal by interpolating a signal whose time axis is disturbed in the case of a high-speed search by the TCI decoder 114 as described later, and then the D / A converters 117a to 117a. At 117c, the original analog Hi-Vision signals Y, PB and PR are restored.

Here, in this reproduction system, the synchronization separation circuits 115a and 115b are respectively provided with the FM demodulation circuit 11
2a and 112b, a synchronization signal is extracted from the reproduced TCI signal FM-demodulated. The PLL circuits 116a and 116b respectively use the synchronization signals extracted by the synchronization separation circuits 115a and 115b to reproduce the reproduction TCI signal as shown in detail in FIG.
The clocks of channels A and B synchronized with the CI signal are generated and supplied to A / D converters 113a and 113b and TCI decoder 114. Further, the synchronization separation circuit 119 outputs the signal GEN. Extract the synchronization signal from LOCK,
The circuit 119 generates a clock according to the synchronization signal, and generates the clock by the TCI decoder 114 and the D / A converters 117a to 117.
c. That is, in FIG. 1, the solid line indicates the flow of the video signal or the video information signal, and the broken line indicates the flow of the clock.

Next, the TCI signal will be described with reference to FIG. 2. The TCI signal is such that the luminance signal Y and the chrominance signal C are one.
Time axis multiplexing is performed in line units, and an H (horizontal) synchronization signal and a burst are added. The TCI encoder 102 alternately assigns the TCI signal to the channels A and B line by line, and
The I signal is a tape pattern as shown in FIG.
h, Bch). Here, recording heads 106a and 106b of channels A and B
Are arranged on a drum (not shown) so as to face each other by 180 degrees. Therefore, a pattern on the tape 109 is formed every two tracks as shown in FIG.

The P for channel A in the reproducing system
LL circuit 116a and PLL circuit 116b for channel B
Are set so that their lock ranges deviate from each other as shown in FIG. 4 so as to correspond to a relative speed change in the case of a high-speed search. Here, as shown in FIG.
At the time of special reproduction, the relative speed between the recording heads 106a and 106b and the magnetic tape 109 changes, so that the time axis of the reproduced video information signal is compressed or expanded. For example +
At 3 × speed, the relative speed is slowed down by about 0.8%, so that the time axis of the reproduced TCI signal is expanded by about 0.8%.
Conversely, at -3 times speed, the relative speed increases by about 2.2%,
The time axis of the reproduced TCI signal is compressed by about 2.2%. Also, in the case of a high-speed search, the value of the compression or expansion on the time axis is further increased. For example, in the case of ± 32 × speed, the value is about ± 18%.

In this embodiment, as shown in FIG.
In order to cope with the double speed to the −4 × speed, the lock range of the channel A is set to 0.827 to the normal reproduction frequency.
1.033 times the frequency range, and +4 to
In order to cope with −32 × speed, the lock range of channel B is 0.983 to 1.18 with respect to the frequency at the time of normal reproduction.
The frequency is set to a range of four times.

Therefore, the A / D converter 11 shown in FIG.
The reproduced TCI signal of channel A converted by 3a is
The time axis becomes accurate at +32 to -4 times speed, and A / D
Reproduction TC of channel B converted by converter 113b
The time axis of the I signal becomes accurate at +4 to -32 times speed. That is, the time axis of each signal of channel A at -4 to -32 times speed and that of channel B at +32 to +4 times speed is disturbed.

Therefore, the TCI decoder 114 uses a simple logic circuit to convert the speed information of the tape 109 into +
Three conditions of 32 to +4 times speed, +4 to -4 times speed, and -4 to -32 times speed are set, and at +32 to +4 times speed,
The line of channel B whose time axis is disturbed is interpolated by the line of channel A whose time axis is accurate. For +4 to -4 times speed, the TCI signals of channels A and B whose time axes are both accurate are used. At −32 × speed, the line of channel A whose time axis is disturbed is interpolated by the line of channel B whose time axis is accurate. Here, since the purpose of the high-speed search is mainly to search recorded contents, sufficient image quality can be realized even if the line of the channel whose time axis is disturbed is interpolated by the line of the channel whose time axis is accurate. .

Therefore, according to the above embodiment, +32
In order to cope with the search from the double speed to the −4 × speed, the lock range of the PLL circuit 116a of the channel A is set to a frequency range of 0.827 to 1.033 times the frequency at the time of normal reproduction, and the + 4 × speed is set. In order to cope with the search up to -32 times speed, the PLL circuit 116b of channel B
Lock range is 0.98 with respect to the frequency during normal playback
The frequency is set in the range of 3 to 1.184 times, the channel whose time axis is accurate is selected according to the speed, and the channel whose time axis is disturbed is interpolated, so that the video can be reproduced well even in the case of high-speed search. can do.

Next, a second embodiment will be described. FIG.
FIG. 7 is a block diagram showing a schematic configuration of a second embodiment of the recording / reproducing apparatus according to the present invention. FIG. 7 is an explanatory diagram showing a lock range of the PLL circuit of the reproducing system in FIG. In the second embodiment, a VTR for dividing a Hi-Vision signal into three channels and recording digitally is shown. The upper part of the drawing shows a recording system, and the lower part of the drawing shows a reproduction system.

In FIG. 6, the input Hi-Vision signal Y,
PB and PR are A / D converters 601a to 601 respectively.
c and converted into a digital signal, and the digitized Hi-Vision signals Y, PB, and PR are converted to DPCM signals.
(Differential PCM) The band is compressed by the encoder 602. Next, an ECC (error correction code) encoder 603
, An error correction code is added.
The signal is added and divided into three channels A to C.
Each of the digital signals of the channels A to C is parallel-serial converted by the modulators 604a to 604c to 8-9 conversion, and the recording amplifiers 605a to 605c.
After being amplified by 605c, recording heads 606a-6
06c on the magnetic tape 609.

Incidentally, in the second embodiment, similarly,
In the recording system, the sync separation circuit 607 extracts a horizontal sync signal and a vertical sync signal from the luminance signal Y or the sync signal SYNCin of the input Hi-Vision signal, and the PLL circuit 608 outputs an A / D signal from the horizontal sync signal and the vertical sync signal. Converter 601
a to 601c, a DPCM encoder 602, an ECC encoder 603, and a master clock for the modulators 604a to 604c.

Channel A recorded on magnetic tape 609
To C, respectively.
To 610c, and the reproduction amplifiers 611a to 611c
After being amplified by 1b, they are integrated by integrators 612a to 612c. Then, the data separators 613a to 613a
613c converts it into a 1-bit digital signal,
9-8 conversion by the demodulators 614a to 614c and serial-parallel conversion, error correction by the ECC decoder 615, expansion of the band by the DPCM decoder 618, restoration to a high-definition signal, and
The original analog Hi-Vision signal is restored by the A converters 619a to 619c.

Here, in the case of digital recording, the sampling clock for A / D conversion of the reproduction system is extracted from the data itself. Each of the comparators 616a to 616c binarizes the reproduced data integrated by the integrators 612a to 612c by comparing the data with a threshold value,
a to 617c are comparators 616a to 616, respectively.
6c, it is locked to the binarized data sequence and generates a sampling clock.

In the second embodiment, as shown in FIG. 7, the lock range of the PLL circuit 617a of the channel A is set to correspond to +10 to -2 times speed, and the lock range of the PLL circuit 617b of the channel B is set. Lock range is +6
P-6 of channel C is set to correspond to
The lock range of the LL circuit 617c is set to correspond to +2 to -10 times speed. In general, a VTR of a digital recording system has a stricter requirement for a steady phase error of a PLL circuit than a VTR of an FM modulation system, so that the lock range of the PLL circuit is narrower.

When the reproduced video information signals of these three channels are converted into a high-definition signal, the speed information of the tape 609 can be obtained from the speed information of +10 to +6 times, as in the first embodiment.
+1 according to five conditions of +6 to +2 times speed, +2 to -2 times speed, -2 to -6 times speed, -6 to -10 times speed
At the time of 0 to +6 times speed, the pixels of channels B and C
At +6 to +2 times speed, the pixel of channel C is interpolated by the pixels of channels A and B. At +2 to -2 times speed, all pixels of channels A to C are used.
At 6 × speed, the pixels of channel A are interpolated by the pixels of channels B and C, and at −6 to -10 × speed, the pixels of channels A and B are interpolated by the pixels of channel C.

Therefore, also in the second embodiment, similarly, the pixels of the channel whose time axis is disturbed are interpolated by the pixels of other channels whose time axis is accurate. Can be played.

[0029]

As described above , according to the present invention ,
Even in playback modes with different playback signal frequencies,
Thus, a reproduction signal can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a waveform diagram showing a TCI signal in the recording / reproducing apparatus of FIG.

FIG. 3 is an explanatory diagram showing a tape pattern in the recording / reproducing apparatus of FIG. 1;

FIG. 4 is an explanatory diagram showing a lock range of the PLL circuit of the reproduction system in FIG. 1;

FIG. 5 is an explanatory diagram showing an operation of a head during special reproduction.

FIG. 6 is a block diagram showing a schematic configuration of a second embodiment of the recording / reproducing apparatus according to the present invention.

FIG. 7 is an explanatory diagram showing a lock range of the PLL circuit of the reproduction system in FIG. 6;

[Explanation of symbols]

 109,609 Magnetic tape 110a, 110b, 610a-610c Reproducing head 114 TCI decoder 116a, 116b, 617a-617c PLL circuit 615 ECC decoder 618 DPCM decoder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956 H04N 5/782-5/783 H04N 9/79-9/898

Claims (3)

(57) [Claims] 1. A reproducing means for reproducing in parallel a plurality of channels of signals from a tape-shaped recording medium on which a large number of helical tracks are formed by a plurality of rotary heads, and having different lock ranges from each other. A reproducing apparatus comprising: a plurality of PLL circuits that generate clocks that are phase-synchronized with signals; and processing means that processes the reproduced signal using the clocks generated by the plurality of PLL circuits. 2. A plurality of special reproduction modes having different tape transport speeds from each other, and each of the plurality of PLL circuits has a lock range corresponding to a reproduction signal frequency in the plurality of special reproduction modes. Claim
Claim 1 Symbol placement of the playback device. 3. A reproducing means for reproducing, in parallel, signals of a plurality of channels from a tape-shaped recording medium on which a number of helical tracks are formed by a plurality of rotary heads; and a first lock range. A first PLL circuit that generates a clock phase-synchronized with the reproduction signal of the first channel; and a second lock range different from the first lock range. A second PLL circuit that generates a clock phase-synchronized with the reproduction signal; and processing means that processes the reproduction signals of the plurality of channels using the clocks generated by the first PLL circuit and the second PLL circuit. And transporting the tape-shaped recording medium at a first speed;
A first special reproduction mode in which the processing means processes a reproduction signal of the first channel using a clock generated by the first PLL circuit; A second special reproduction mode in which the processing means conveys at a different second speed and the processing means processes a reproduction signal of the second channel using a clock generated by the second PLL circuit. .