JP2944851B2 - Magnetic recording / reproducing 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 VHS type VTR.
The present invention relates to a magnetic recording and reproducing device such as a (video tape recorder).

[0002]

2. Description of the Related Art In a conventional VHS system VTR, usually,
In the standard mode (SP mode) and in the triple mode (EP mode) in which the recording time is tripled by reducing the running speed of the magnetic tape to one third of that in the standard mode, the recording / reproducing operation is performed.
It is configured to be able to reproduce.

[0003] The inventors of the present application further reduced the running speed of the magnetic tape to 1/6 of that in the standard mode, and provided a configuration capable of recording / reproducing in the 6-times mode in which the recording time was 6 times longer. (See Japanese Patent Application No. 4-208069).

[0004] VHS system V with 6 times mode as described above
The TR includes an H array circuit 53 in the video signal processing circuit, for example, as shown in FIG. At the time of recording,
A composite video signal input from the outside through the signal input terminal T _IN is first passed from an AGC (automatic gain control circuit) 51 to a Y / C separation circuit 52, so that a Y signal (luminance signal) and a C signal (chroma signal) are output. ) and to be separated, Y signal is input to the above-mentioned H arranging circuit 53 via the input signal changeover switch S _I. In the H arrangement circuit 53, H arrangement processing for changing the delay time for each field is performed.

[0005] The H arrangement processed signal processed through the H arrangement circuit 53 is then converted to an LPF (low-pass filter) 54.
A sub-emphasis & de-emphasis circuit 55, a main emphasis circuit 56, a white clip & dark clip circuit 57, and an FM modulator 58 are sequentially processed. Next, the MIX circuit (synthesis circuit) 59 synthesizes the recording color signal with the recording color signal, and supplies the recording color signal to the magnetic head to be recorded on the magnetic tape. This recording state is recorded as a so-called H arrangement state in which the positions of the horizontal synchronization signals are arranged in a straight line even in the 6 × mode by the above-described H arrangement processing.

On the other hand, in the reproduction mode, a reproduction FM signal reproduced from the magnetic tape 61 by the magnetic head 62 is supplied to a head amplifier & RF-AGC circuit 63 and an FM equalizer 64.
Double limiter 65, is sequentially passed through the processing to the FM demodulator 66, the main de-emphasis circuit 67, the signal is, the inputted input signal via the switch S _I to the H side by side circuit 53, H sequence inverse correction process Done.

The signal subjected to the H arrangement reverse correction processing is LP
F54 and a sub-emphasis & de-emphasis circuit 55, a noise canceller 68, and an image quality adjustment circuit 69 are sequentially processed and processed by a MIX circuit (synthesis circuit) 70.
Is combined with separately processed reproduced color signal through unillustrated color signal processing circuit, is outputted to the video signal output terminal T _OUT via the first output signal changeover switch S _01. At this time, the Y signal from the image quality adjustment circuit 69 is simultaneously output to the S terminal T _S via the second output signal changeover switch S ₀₂ .

The output signal to the S terminal T _S is also sent to a synchronization separation circuit 71, which separates a composite synchronization signal. This synchronizing signal is supplied to a color signal processing circuit (not shown) and also to a control signal generating circuit 72 composed of a microcomputer or the like. In the control signal generation circuit 72, field discrimination is performed based on the vertical synchronization signal from the synchronization separation circuit 71, and the time interval is always 26.2.
An H arrangement control signal is generated so as to be 5H. And
The processing operation of the H-arrangement circuit 53 is controlled by this control signal.

[0009] Incidentally, the stop state of the VTR other than the recording and playback mode, the so-called EE (Electric-to-Electric) mode, the output from AGC51 via the first output signal changeover switch S ₀₁ to the video signal output terminal T _OUT A signal, and an output signal from the Y / C separation circuit 52 are output to the S terminal T _S via the second output signal changeover switch S ₀₂ . Therefore, on the monitor connected to these terminals T _OUT and T _S , an image corresponding to an external composite video signal input to the signal input terminal T _IN is displayed.

Conventionally, when switching from the EE mode to the reproduction mode, the first and second output signal changeover switches S ₀₁ and S ₀₂ are used to prepare for a mechanical mechanism such as tape loading on a rotating drum. About 500 after completion
Screen switching control signal EE (L) generated with a delay of msec
Accordingly, the input signal changeover switch S _I simultaneously switched, thereby, monitor screen is controlled so switched to the playback screen from EE screen.

[0011]

However, in the above-described conventional control structure, when the mode is shifted from the EE mode to the reproduction mode, the first and second output signal changeover switches S _{01 are set.}
· S at the same time as the EE screen monitor by switching the _02's switches to the playback screen is switched input signal changeover switch S _I. That is, at this point, the input to the H arrangement circuit 53 is switched to the reproduced video signal, and the control signal generation circuit 72 starts field discrimination for the reproduced video signal. Therefore, after the screen is switched, the time interval of the vertical synchronization signal is 265.5 until the field determination result is obtained.
There is a problem that H is not constant and V jitter occurs on the monitor screen.

[0012]

In order to solve the above-mentioned problems, a magnetic recording / reproducing apparatus according to the present invention comprises: an H-arrangement circuit for performing a predetermined delay process on a video signal for each field; a sync separation circuit; A VHS type magnetic recording / reproducing apparatus comprising: a control signal generating means for generating a control signal to the H-arrangement circuit based on the synchronization signal separated by the separation circuit.
An input signal changeover switch for changing the input to the H parallel circuit from an external video signal input from the outside through a signal input terminal to a reproduction signal on a magnetic tape when switching from the E mode to the reproduction mode; A field discrimination signal changeover switch for switching an input to the separation circuit from an external video signal to an H arrangement processing signal processed through an H arrangement circuit, and an output to a monitor output terminal from the external video signal to the H arrangement processing signal A video signal based on the output signal is provided with an output signal changeover switch that switches the input signal changeover switch and the field discrimination signal changeover switch at a predetermined time delay from the time of switching.

[0013]

In the magnetic recording / reproducing apparatus having the above configuration, the EE
When the mode is shifted to the reproduction mode, first, the input signal changeover switch and the field discrimination signal changeover switch are switched, whereby the input to the H arrangement circuit is switched to the reproduction signal on the magnetic tape and the control signal generation is performed. In the means, the H arrangement processing signal processed through the above H arrangement circuit is supplied through the synchronization separation circuit, whereby the field discrimination based on the reproduction signal is started. And
After that, for example, a predetermined time delay of about 500 msec,
The output signal changeover switch is switched, and E is displayed on the monitor.
The screen is switched from the E screen to the playback screen.

As described above, in the above, before the screen is switched, field discrimination based on the reproduction signal is started by the control signal generation means, whereby the time interval of the vertical synchronizing signal in the reproduction signal is kept constant at 265.5H. In this state, the screen can be switched on the monitor, so that it is possible to display a high-quality image without V jitter from the beginning of the screen switching.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a VHS type V with a 6 × mode.
FIG. 2 shows a signal processing system diagram of a Y signal (luminance signal) in the TR. First, referring to the figure, at the time of recording (REC)
The control configuration of the recording system according to the present embodiment will be described along the flow of signals in.

As shown in FIG. 1, an AGC (automatic gain control circuit) 1 and a Y / C separation circuit 2 are connected to a signal input terminal T _IN.
Are sequentially connected. A composite video signal input from the outside through the signal input terminal T _IN is amplified to an appropriate amplitude by the AGC 1 and separated into a Y signal (luminance signal) and a C signal (color signal) by the Y / C separation circuit 2. Is done.

The separated C signal is supplied to a color signal processing circuit (not shown), while the Y signal is input to the H arrangement circuit 3 via a _first switch S1 as an input signal switch. . The above-mentioned Y signal, via a second changeover switch S ₂ as a field discriminating signal changeover switch, it is input to the synchronization separation circuit 21, a third
S via changeover switch S ₃ (output signal changeover switch)
The signal is output to the terminal T _S.

The H-arrangement circuit 3 performs signal processing for changing the delay time for each field. As shown in FIG. 2, an A / D converter 3a for A / D-converting an input signal,
0.25H delay circuit 3 connected in parallel to the through line 3b for supplying the / D-converted signal as it is to the output side
Which one of the c · 0.5H delay circuit 3d · 0.75H delay circuit 3e, the through line 3b and each of the delay circuits 3c · 3d · 3e is to be processed, is switched according to the H arrangement control signal described later. A changeover switch 3f and a D / A converter for D / A converting and outputting a signal selected by the changeover switch 3f.
/ A converter 3g.

In the H-arrangement circuit 3 having the above configuration, when recording (REC) in the 6 × mode, 0H ·
The signal is recorded on the magnetic tape in the H-arranged state by performing the H-arrangement process for sequentially delaying 0.25H, 0.5H, 0.75H. It should be noted that playback in the 6 × mode (P
In B), the H arrangement reverse correction, which is the reverse of the above, is performed by the H arrangement circuit 3.

As shown in FIG. 1, the H arrangement circuit 3 has L
A PF (low-pass filter) 4 and a sub-emphasis & de-emphasis circuit 5 are sequentially connected. From the Y signal processed through the H arrangement circuit 3, a low frequency component is extracted by the LPF 4. Then, at the time of recording (REC), a process of sequentially passing through the sub-emphasis & de-emphasis circuit 5 and the main emphasis circuit 6 to emphasize the high frequency of the signal output from the LPF 4 is performed. This signal is then subjected to white clip and dark clip processing in a white clip & dark clip circuit 7, and then input to an FM modulator to be FM-modulated. Then, the MIX circuit (synthesis circuit) 9 synthesizes the recording color signal output from the color signal processing circuit with the recording color signal and supplies it to a magnetic head (not shown) to perform recording on a magnetic tape.

At the time of the above recording, the Y / C separated circuit 2 separates the Y terminal from the S terminal T _S as described above.
Signal is output via a third changeover switch S _3. At the same time, the composite video signal after passing AGC1 is, the fourth through the switch S ₄ (output signal changeover switch), is output to the video signal output terminal T _OUT, the terminals _{T S} · T _OU T
The video at the time of recording is displayed on the monitor connected to.

Next, the control configuration of the reproduction system of the present embodiment will be described along the flow of signals during reproduction (PB).

A reproduction FM signal obtained from the magnetic tape 11 is amplified through a head amplifier & RF-AGC circuit 13 by a pair of magnetic heads 12 attached to opposing positions of a rotating drum (not shown), and , Into a signal of constant amplitude. The head amplifier & RF-AGC circuit 13 includes an FM equalizer 14 and a double limiter 1.
5. FM demodulator 16 Main deemphasis circuit 17
Are sequentially connected, a process of balancing upper and lower sidebands is performed by an FM equalizer 14, and a limiter is divided into a high band and a low band by a double limiter 15, and then an FM demodulator 16 Is FM-demodulated. Then, the main by de-emphasis circuit 17, after the processing for suppressing the high frequency of the reverse to the Y signal is performed from the main emphasis circuit 6 of the, H arranging circuit 3 via a first changeover switch S ₁ described above And the H arrangement reverse correction process is performed.

The signal subjected to the H arrangement reverse correction processing is sequentially passed through the LPF 4 and the sub-emphasis & de-emphasis circuit 5 to take out a low-frequency component and to sequentially perform processing for suppressing the high range of the Y signal. Then, the signal is input to the noise canceller 18 to cut high-frequency noise. Further, after the image quality adjustment processing is performed by the image quality adjustment circuit 19, the MIX circuit (synthesis circuit) 20 separately reproduces the output signal of the head amplifier & RF-AGC circuit 13 through a color signal processing circuit (not shown). The signal is synthesized with the color signal and output to the video signal output terminal T _OUT via the fourth switch S ₄ . At this time, the Y signal output from the image quality adjustment circuit 19 is simultaneously output to the S terminal T _S via the third changeover switch S _3, and is also output to the _{S /} T terminal via the second changeover switch S _2. The signal is input to the circuit 21.

In the sync separation circuit 21, the image quality adjustment circuit 19
The composite synchronizing signal is separated from the output signal, and the synchronizing signal is supplied to the above-described color signal processing circuit and also input to a control signal generating circuit (control signal generating means) 22 including a microcomputer. This control signal generation circuit 22
In the above, a field determination is performed to determine whether a head switching pulse for switching the pair of magnetic heads 12 and the vertical synchronization signal separated as described above are in a predetermined phase,
In the case of a phase shift, an H arrangement control signal for operating the H arrangement circuit 3 is generated so as to eliminate the phase shift by changing the delay time of each field of the H arrangement circuit 3,
It is sent to the arrangement circuit 3. Thus, the above-described H arrangement reverse correction in the H arrangement circuit 3 is performed.

The C signal separated by the Y / C separation circuit 2 at the time of recording is subjected to the same signal processing as that of a normal VHS system VTR, and is converted into a low frequency band of 629 kHz.
H arrangement processing is performed similarly to the signal. When performing such processing of the C signal, processing such as extracting the burst portion of the C signal from the composite synchronization signal separated from the Y signal is performed in the 6-times mode of the present embodiment, as in the related art.
Therefore, the synchronization separation output supplied to the color signal processing circuit needs to be separated from the Y signal before the H arrangement processing in the H arrangement circuit 3. For this reason, the synchronization separation circuit 2
The second changeover switch S ₂ provided at the input stage to 1, by the time of recording the second switching of the changeover switch S _2, the above Y /
The Y signal separated by the C separation circuit 2 is input to the synchronization separation circuit 21.

The monitor connected to the video signal output terminal T _OUT and the S terminal T _S is provided with a VTR stopped state,
In other words, when in the EE (Electric-to-Electric) state,
At the time of recording, since the third and fourth changeover switches S ₃ and S ₄ are respectively located on the EE side, the composite video signal after passing through the AGC 1 is separated by the Y / C separation circuit 2 as described above. And the output Y signal. On the other hand, at the time of reproduction, the third and fourth changeover switches S ₃ and S ₄ are respectively switched to the PB side from the above, so that the reproduced video signal from the MIX circuit 20 is output to the video signal output terminal T _OUT . The reproduced luminance signal from the image quality adjustment circuit 19 is output to the S terminal T _S , whereby the reproduced video from the magnetic tape 11 is displayed on the monitor.

The first and second changeover switches S ₁
· S ₂ also, third and fourth change-over switch S _{3-S 4} described above
Is switched between the EE side and the PB side in the same manner. In this embodiment, particularly, when the switching from the EE state to the reproduction state is performed, the loading of the magnetic tape 11 onto the rotating drum is performed. When the operation is completed and the reproduction FM signal starts to be generated, the voltage level changes from low to high.
The first and second changeover switches S ₁ and S ₂ are first switched by a reproduction control signal AL (H) which is controlled by a control device (not shown) so as to change to. afterwards,
The voltage level changes from low to high with a delay of about 500 msec.
The third and fourth changeover switches S ₃ and S ₄ are switched by the screen change control signal EE (L) controlled by the control device so as to change to h.

Next, the operation of the VTR having the above-described configuration, particularly when shifting from the EE state to the reproduction state, will be described.

In the EE state, the first to fourth changeover switches S
₁ to S ₄ are respectively positioned on the EE side shown in FIG. At this time, when a composite video signal from an external input such as a television tuner or a video camera is input through the signal input terminal T _IN , the video signal from the AGC 1 is output through the video signal output terminal T _OUT , and the video signal is output through the S terminal T _S. , Y / C separation circuit 2 is output to a monitor connected to these terminals T _OUT and T _S.

In this state, when a recording switch (not shown) is operated to enter the recording mode, the first to fourth recording switches are set.
The changeover switches S _{1 to} S ₄ are held at the above positions. Therefore, the processing from the H arrangement circuit 3 to the MIX circuit 9 is sequentially performed on the composite video signal input to the signal input terminal T _IN, and Recorded on tape. An image based on the recorded composite video signal is displayed on a monitor.

When the switching from the EE state to the reproduction mode is performed, the operation of the mechanical mechanism such as loading of the magnetic tape 11 on the rotating drum is started. When the operation is completed, the reproduction control signal is output. AL (H)
Changes from the low level to the high level, whereby the processing operation in the head amplifier & RF-AGC circuit 13 is started. At the same time, the first changeover switch S ₁ and the second changeover switch S ₂ are switched from the EE side to the PB side by the reproduction control signal AL (H), respectively. The H arrangement processing signal after the H arrangement reverse correction through the circuit 3 is
Is input through the second changeover switch S _2.

Thus, the control signal generation circuit 22 starts field discrimination based on the reproduction signal, and performs an operation of generating the H arrangement control signal to be sent to the H arrangement circuit 3 based on the phase of the vertical synchronization signal in the reproduction signal. Start.

Thereafter, with a delay of about 500 msec, the screen switching control signal EE (L) changes from the low level to the high level, whereby the third / fourth switching switch S
₃ · S ₄ is switched from EE side PB side.
As a result, a reproduced video signal is output through the video signal output terminal T _OUT and the S terminal T _S, and the screen on the monitor is switched from the EE screen to the reproduced screen.

As described above, V in this embodiment is
In the HS system VTR, the screen on the monitor is EE
When switching from the screen to the playback screen,
Before sec, the control signal generation circuit 22 starts field discrimination in the reproduced video signal, and generates an H-arrangement control signal such that the time interval of the vertical synchronizing signal is 262.5H. Note that at least four frames of time are required to determine a field, which is 120 msec, and the screen switching control signal EE (L) is changed from a low level to a high level.
It is enough time to reach the level.

With the above switching control, the monitor screen can be switched from the EE screen to the reproduction screen when the vertical synchronizing signal interval is constant at 262.5H. Therefore, from the beginning of the switching, a high-quality image without V jitter can be displayed. Further, in the above embodiment, the third and fourth change-over switch S _{3-S 4} whereas switching the conventional Likewise screen switching control signal EE (L), the first and second changeover switches S ₁ - S ₂ The above-mentioned reproduction control signal AL (H) is used as a control signal for switching earlier than the above. Therefore, since the configuration does not require any special means only for performing the switching timing control as described above, the overall configuration can be simplified.

[0038]

As described above, according to the magnetic recording / reproducing apparatus of the present invention, when the mode is switched from the EE mode to the reproducing mode, the input to the H parallel circuit is supplied to the external video signal input from the outside through the signal input terminal. , An input signal changeover switch for changing over to a reproduction signal on a magnetic tape, a field discrimination signal changeover switch for changing over the input to the sync separation circuit from an external video signal to an H arrangement processed signal processed through an H arrangement circuit, and a monitor. An output signal switch for switching the output to the output terminal from an external video signal to a video signal based on the H arrangement processing signal by a predetermined time later than when the input signal switch and the field discrimination signal switch are switched. This is the configuration provided.

Therefore, before switching from the EE screen to the reproduction screen on the monitor, the control signal generation means starts field discrimination based on the reproduction signal, whereby the time interval of the vertical synchronizing signal in the reproduction signal becomes 265. Since the screen can be switched on the monitor in the state where it is constant at 5H, it is possible to display a high-quality image without V jitter from the beginning of the screen switching.

[Brief description of the drawings]

FIG. 1 shows a VH with a 6 × mode in one embodiment of the present invention.
FIG. 3 is a control block diagram illustrating a schematic configuration of a luminance signal processing system of the S-system VTR.

FIG. 2 is a control block diagram showing a configuration of an H arrangement circuit in the luminance signal processing system.

FIG. 3 is a control block diagram showing a schematic configuration of a luminance signal processing system of a conventional VHS type VTR with a 6 × mode.

[Explanation of symbols]

3 H Arrangement Circuit 11 Magnetic Tape 21 Sync Separation Circuit 22 Control Signal Generation Circuit (Control Signal Generation Means) S ₁ First Changeover Switch (Input Signal Changeover Switch) S ₂ Second Changeover Switch (Field Discrimination Signal Changeover Switch) S _3rd 3 switch (output signal switch) S ₄ 4th switch (output signal switch) T _IN signal input terminal T _OUT video signal output terminal (monitor output terminal) T _S S terminal (monitor output terminal)

Claims (1)

(57) [Claims] An H-arrangement circuit for performing a predetermined delay process on a video signal for each field, a synchronization separation circuit, and a control for generating a control signal to the H-arrangement circuit based on a synchronization signal separated by the synchronization separation circuit. In the VHS type magnetic recording / reproducing apparatus provided with a signal generating means, when the mode is switched from the EE mode to the reproducing mode, the input to the H parallel circuit is changed from the external video signal inputted from outside through the signal input terminal to the magnetic field. An input signal changeover switch for switching to a reproduction signal on a tape, a field discrimination signal changeover switch for changing an input to the sync separation circuit from an external video signal to an H arrangement processed signal processed through an H arrangement circuit, and a monitor output terminal Output from the external video signal to the video signal based on the H arrangement processing signal, the input signal changeover switch and the field discrimination. Magnetic recording and reproducing apparatus characterized by the output signal changeover switch for switching delayed a predetermined time is provided than switching the No. changeover switch.