JPS583433B2 - TV show - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for shaping a synchronization signal portion of a television signal reproduced from a VTR or the like.

Television signal regenerators, especially broadcast VTRs, reproduce composite video signals (hereinafter abbreviated as TAPE and VIDEO).
The synchronization signal phase of is the local synchronization signal (hereinafter referred to as REF, SYNC
In some cases, it may be necessary to match the phase of

Operating the VTR in such an operating state is referred to as VH lock mode, H lock mode, or ■lock mode, depending on the mode, as described below.

VH lock mode means that the synchronization signal phase of TAPE, VIDEO and the phase of REF, SYN O are vertical synchronization signal (V
SYNC) and a horizontal synchronizing signal (HSYNC) are either completely matched or fixed to a constant phase relationship.

What is H lock mode? TAPE, VIDEO H, SYN
This means operating the VTR so that only the C phase completely matches that of REF and SYNC, or is fixed to a constant phase relationship.

■What is lock mode?■ of TAPE, VIDEO, SYN
This means operating the VTR so that only the C phase completely matches that of REF and SYNC, or is fixed to a constant phase relationship.

Also, when operating a broadcast VTR, TAPE and VID are generally used.
The synchronization signal portion of the EO (hereinafter abbreviated as TAPE, SYNC) is waveform-shaped by a stabilizing amplifier called a processor.

Generally, three methods are used for this waveform shaping, and these are shown in FIGS. 1 to 3.

The method shown in FIG. 1 is called the GATED, SYNC mode, in which the synchronization signal from TAPE VIDEO is once separated by a synchronization separator 3, and then shaped by a synchronization signal shaper 5.
The video signal that has passed through the video signal shaping section 2 and the synchronization signal mixer 4
Mix again.

A locked oscillator (including AFC, APC oscillators, etc.) 8 and a gate signal generator 6 are circuits that generate gate pulses and the like for separating and shaping the synchronizing signal section.

TAP due to the gate action and shaping action of each circuit described above.
E SYNO noise, waveform distortion, etc. can be removed to a considerable extent, but large dropout noise and SYNC
It is impossible to completely eliminate jitter peculiar to VTRs and time axis fluctuation components called drift remaining at the leading edge.

The method shown in Figure 2 is a method called REGENERATED SYNC mode (abbreviated as REGEN mode).
TAPE SYN from PE VIDEO with sync separator 3
After separating C, the locked oscillator 8 is driven by this synchronization signal, the synchronization signal generator 9 regenerates the synchronization signal from the oscillator output pulse, and this output is sent to the video signal shaping section 2 by the synchronization signal mixer 4. mixed with the output video signal.

In this method, as mentioned above, the synchronization signal part is regenerated by a locked oscillator, such as the output of an AFC oscillator, so it is less affected than the method shown in Figure 1, and the amount of time axis fluctuation is also averaged, reducing its influence considerably. However, if large dropout noise occurs near the sync signal section, a pseudo sync signal will be generated at the output of the sync separator 3, causing the locked oscillator to malfunction. ing.

Furthermore, since the amount of time axis variation is only averaged and not completely removed, the synchronization signal portion of the VTR output signal remains with some time axis variation.

For this reason, there was a risk that the distortion would accumulate, especially when creating a duplicate tape (dubbing).

In order to eliminate these drawbacks, the TA
PE VIDEO (7) Completely REFS the synchronization signal section
A method of substitution with YNO 1 0 was considered.

Set this to EXTERNAL SYNC mode (EXT S
(abbreviated as YNC3 mode).

This method completely eliminates the above drawbacks, but on the other hand, TAP
E VIDEO is REF SYNC! completely that SY
There is a constraint that reproduction must be performed so that the NC phases match.

Furthermore, if the phase relationship does not match for some reason, the video signal section and the synchronization signal section become completely unrelated, and the screen cannot be reproduced normally on the receiver.

On the other hand, when a VTR is playing in the lock mode, the lock may be lost if there is a disturbance such as a large dropout noise or a temporary interruption of the video signal.

Furthermore, once the lock is released, it will be 1 until it is relocked.
It often takes several seconds.

In particular, it takes time to lock synchronization.

Therefore, in such a case, the VT
When operating the VTR, a normal screen cannot be displayed on the receiver for more than 10 seconds, which is a fatal drawback for a broadcast VTR.

Therefore, except for operations such as dubbing, it was normal to operate in the mode shown in FIG. 1 or 2.

The present invention provides a new reproduction method that solves the drawbacks of the above-mentioned methods.

FIG. 4 shows an example of the method of the present invention.

A V synchronization signal separator 14 separates only the V synchronization signal portion from the TAPE VIDEO 1 reproduced in the H lock mode.

On the other hand, the reference horizontal synchronization signal (abbreviated as REF・H) 11 obtained by extracting only HSYNC from REF SYNC is sent to HSYNC (T
The locked oscillator 15 is driven after the phase is shifted so as to have a required phase relationship with the APE.H (abbreviated as APE.H).

One of the outputs of the locked oscillator 15 drives a horizontal synchronization pulse generator 16 to generate required horizontal synchronization related pulses such as a horizontal synchronization signal and a horizontal blanking signal.

The other output of the oscillator 15 enters a vertical synchronizing pulse generator 1T, which will be described later, and becomes a clock pulse for the counting circuit 17.

On the other hand, the (2) pulse separated from the TAPE VIDEO by the V synchronization signal separator 14 becomes the (2) reset pulse for resetting the counting circuit in the (2) reset pulse generator 18, which will be described later.

The vertical synchronization pulse generator 17 can be constructed using various circuit systems, but a typical example will be described here with reference to FIG. 5.

R which is the output of the locked oscillator 15 shown in FIG.
A 31.5 KHz (twice the frequency of H synchronization) pulse 20 synchronized with EF-H drives flip-flops constituting 10 stages of binary counting circuits 22-31.

In this case, each flip-flop operates on the falling edge of the pulse.

On the other hand, the output 21 of the V reset pulse generator 18 shown in FIG. 4 is connected to the reset terminal of the flip-flop.

As shown in Figure 5 A, B, and C, the above 18 is a
The TAPE SYNC separated from the APE VIDEO is integrated to generate the ■ pulse as shown in Figure 1, and Schmidtli, the other 14 components, drives the circuit with this V pulse, creating the V IJ as shown in Figure C. Generates a set pulse and outputs it.

Therefore, at the reset terminal of the flip-flop,
As shown in Figure C, a pulse with a leading edge will enter between the leading edge point A (2) of the TAPE-V and the first serration point E (2).

Therefore, the output of the first stage flip-flop 22 has a waveform as shown in E, and the output of the second stage flip-flop 22 has a waveform as shown in E.
The output of the flip-flop 24 in the third stage has a waveform as shown in FIG.

In this way, in the same field, the start phase of the pulse waveform of each stage is sequentially delayed, and the end phase is reset by the waveform C, so that the flip-flop 31 of the 10th stage
The output is 60H synchronized with TAPE■ as shown in
It becomes a z pulse.

Therefore, when the four pulses E, H, G, and J are used to drive the NAND gate 32, which generates a low level output when all of its input terminals are at high level, the following 21
The NAND gate generates a pulse 33 with a leading edge corresponding to a point.

The 31.5KHz pulse shown in 2 is generated from REFH synchronized with tape H as mentioned above, and since A is TAPE SYNC, points A → D and points K - ■ are in principle coincident. It turns out.

Therefore, ri is a pulse whose phase coincides with the leading edge of V synchronization, and using this pulse as a reference, by the same means as described above,
(2) All pulses related to (2) such as blanking signals and V equalization pulses can be generated.

These output signals are mixed with the H-related pulses in the V and H pulse mixers shown in FIG. The signals are mixed to form a composite video signal.

As can be seen from the above explanation, in the method of the present invention, TAPE VI
Since only the synchronization signal section (1) is extracted from the DEO as a reset pulse, the VTR only needs to be operated in the H lock mode.

In general, in the H lock mode, even if the lock is once lost due to a disturbance, the H lock mode recovers much faster than the VH lock mode, and recovers in less than a few seconds, usually less than 1 second.

Therefore, due to disturbance, the TAPE・H phase changes to REF・H.
Even if the phase deviates, it can be restored in about 1 second at most, so it can be said that the restoration is done to a degree that does not pose any practical problem.

In addition, I used and played HS YN C, which has no negative effects such as waveform distortion and noise obtained from REF・H.■
Since the synchronization signal section is also made from the REEH pulse, it is a TAP that eliminates the above drawbacks even in dubbing work etc.
E VIDEO can now be used.

Furthermore, as mentioned above, the synchronous signal separator is generally less affected by dropout noise due to the composite synchronous signal separator being composed of an integrating circuit, etc., so it is more effective than the conventional method shown in Figures 1 and 2. It has the advantage of being able to use a stable synchronization signal.

Note that the phase control signal 12 is REF・H and TAPE.
- Obtained by detecting the average phase shift of H, REF-
12 and 13 can be omitted in a regenerator that operates only when the phases of H and TAPE/H are completely matched.

Also, the synchronization signal regeneration method has been simplified to TAPE SYNC.
It is also conceivable to directly extract the synchronization signal part from the above method and achieve almost the same effect as the above method.

In this case, it is sufficient to transform 14, 17, and 18.

Although the above explanation uses a broadcasting VTR as an example, it goes without saying that the method of the present invention can be applied not only to other VTRs that require similar operation, but also to other television signal reproducing devices that operate for the same purpose. stomach.

[Brief explanation of the drawing]

1 to 3 show system diagrams of conventional reproduction systems. FIG. 4 shows an example of a system diagram of a regeneration method according to the present invention, and FIG. 5 shows a system diagram and a waveform diagram of a V synchronization pulse generator.

Claims (1)

[Claims] 1. In a television signal regenerator that reproduces at least the horizontal synchronizing signal part of the reproduced television signal by matching the phase of the horizontal synchronizing signal with that of the reference synchronizing signal or fixing it to a certain fixed phase relationship, the horizontal synchronizing signal of the reproduced television signal The vertical synchronizing signal part is replaced with a reference horizontal synchronizing signal related pulse or a horizontal synchronizing signal related pulse generated therefrom, and the vertical synchronizing signal part is synchronized with the vertical pulse separated from the reproduced television signal and the horizontal synchronizing signal part, and the vertical synchronizing signal part is replaced with a pulse related to the reference horizontal synchronizing signal or a horizontal synchronizing signal related pulse generated therefrom. A television signal reproducing method that has a synchronization signal part shaping method that replaces the vertical synchronization signal with a pulse related to a vertical synchronization signal generated based on a signal having a frequency.