JP2890861B2 - Phase adjustment 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 digital phase adjuster for adjusting the phase of a video signal.

[0002]

2. Description of the Related Art Conventionally, when a video signal is mixed using a main adjustment device and a sub-adjustment device, it is necessary to accurately match the color phase and the like of the video signal. In the sub-adjustment device, the digital processing of the video signal is performed. Although the stability of the digital processing is improved, the delay time is greatly increased, for example, about 1/4 to 1H (H: horizontal cycle). Has been delayed. Therefore, the digitally processed video signal and the unprocessed video signal have significantly different phases. Since the main adjustment device switches and transmits a plurality of video signals, a phase adjustment device such as an automatic color phase adjustment device or a frame synchronizer is provided on the output side of the switch, and the phase adjustment device adjusts the phase of the video signal. It is carried out.

FIG. 4 is a block diagram showing a video switcher provided with a conventional phase adjusting device. An input terminal 41 receives a video signal digitally processed by a sub-adjustment device (not shown) and an unprocessed video signal. The switch 42 receives various video signals from the input terminal 41, switches these appropriately, and outputs them. The phase adjusters 43 and 44 receive the video signal output from the switch 42 and the reference signal supplied from the reference signal input terminal 47, respectively.
The phase of the video signal is adjusted according to the reference signal and output. The mixing amplifier 45 receives the video outputs output from the phase adjusters 43 and 44, mixes and amplifies them, and outputs the amplified output to an output terminal 46.

When a frame synchronizer is used as the phase adjusters 43 and 44, a still image is temporarily output at the time of switching response, or a delay time between input and output is increased, causing a difference between video and audio. There are cases. For this reason, the phase adjusters 43 and 44 that can adjust the phase in one horizontal cycle are also used.

[0005]

However, in a video switcher provided with the above-mentioned conventional phase adjusting device, when a plurality of sub-adjusting devices for performing digital processing of a video signal are connected in cascade, the phase difference of the video signal is reduced. 1H
, Phase adjustment becomes difficult. That is, when the phase difference is 1H or less, the phase can be adjusted relatively easily. However, when the phase difference is several Hs, the phase difference cannot be determined at a high speed. There is a problem that it is difficult to complete the phase adjustment within the vertical blanking period of the video signal.

In this case, the phase adjuster 43 is connected to the switch 42
However, if the number of inputs of the switch 42 is larger than the number of outputs, it is necessary to provide many phase adjusters 43, which increases the manufacturing cost. Therefore, the phase adjuster 43 needs to be provided on the output side of the switch 42. The example in FIG. 4 is an example in which the mixed amplifier is a single system.
But increase this further and cascade mixed amplifiers.
Things have also been done. For this reason, the second stage mixed amplifier
The input is the signal of input 41 by the delay of the first stage signal processing.
It is necessary to delay the mixing amplifier at the output side of the switch.
In the input stage, the signal from the input 41 and the
When it is appropriate to adjust the phase of the signal together
There is. The switch 42 at the preceding stage of such video mixing is
The so-called blanking switching is being performed. Normally, switching
As the timing, the equivalent pulse ends after the vertical synchronization.
Was done in the vicinity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a phase adjusting apparatus capable of completing phase adjustment within a vertical blanking period of a video signal.

[0008]

According to the present invention, there is provided a phase adjusting apparatus which counts each horizontal cycle of a video signal and resets the same with a vertical cycle of the video signal .
A signal adder for adding the line number data signal al to the horizontal blanking period of the video signal, from the signal adder
Receives signals and switches at vertical blanking timing
A switch, and the line number from the video signal output from the switch.
Adjusted according to the phase difference between the reference signal to separate the issue data signal
A phase adjustment unit that performs the data adjustment.
Line number included in signal and reference signal supplied from outside
And the comparison result of this comparison circuit
Delaying the video signal up to 12H on the basis of
And an extension circuit .

[0009]

In the present invention, the counter counts every horizontal cycle of the video signal and resets it at the vertical cycle of the video signal. Therefore, the data signal of the counter corresponds to the scanning line number of the video signal. In addition, the signal adding unit adds the data signal of the counter to a horizontal blanking period of the video signal. The scanning line number of the signal can be easily determined. Accordingly, the phase adjuster can separate the data signal from the video signal and adjust the phase of the video signal in units of a horizontal cycle according to the data signal.

According to the present invention, since the phase of the video signal can be adjusted at a high speed by using the data signal added to the video signal, the phase adjustment is completed within the vertical blanking period of the video signal. be able to.

Further, the phase adjusting section can be configured as described below. That is, the comparison circuit detects a phase difference between the data signal and the reference data signal by comparing the data signal added to the video signal with a reference data signal supplied from the outside. The delay circuit appropriately delays the video signal based on a comparison result of the comparison circuit. Thereby, the phase of the video signal can be adjusted.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a video switcher provided with a phase adjusting device according to an embodiment of the present invention, FIG. 2 is a block diagram showing an insert circuit of the phase adjusting device according to the present embodiment, and FIG. It is a block diagram showing a phase adjustment part of a phase adjustment device concerning an example.

The insert circuit 4 receives a video signal from the input terminal 1, adds a predetermined data signal to the video signal, and outputs the video signal. That is, as shown in FIG. 2, the video signal is input to the input terminal 21 of the insert circuit 4, and is supplied to the synchronous data generation circuit (counter) 23 and the signal adding unit 24. The synchronous data generating circuit 23 synchronously separates the video signal input to the input terminal 21, counts each horizontal period, and resets the vertical period. The signal adding unit 24 adds the data signal output from the synchronous data generating circuit 23 to the horizontal blanking period of the video signal, and outputs the video signal to the output terminal 22 of the insert circuit 4.

The switch 7 receives video signals output from the plurality of insert circuits 4 and switches these appropriately to output.

Each of the two phase adjusters 5 receives the video output output from the switch 7 and the reference signal supplied from the reference signal input terminal 2, and outputs the video signal according to the reference signal. Adjust the phase and output. That is, as shown in FIG. 3, the video signal (the video signal to which the data signal is added) output from the switch 7 is input to the input terminal 31 of the phase adjustment unit 5, and the delay circuits 34 to 37 and the phase comparison circuit 38. The phase comparison circuit 38 receives a reference signal from the reference signal input terminal 33, and has a counter that counts every horizontal period of the reference signal and resets it at a vertical period of the reference signal. The phase comparison circuit 38 receives the reference signal from the reference signal input terminal 33.
It is counted every horizontal cycle of this reference signal.
With a counter that resets with the vertical period of the reference signal
I have. Then, the phase comparison circuit 38 compares the data signal added to the video signal with the reference data signal output from the counter. The delay circuits 34 to 37 are connected in cascade with each other and each have a delay time of 1H. The switch 40 switches the number of connection stages of the delay circuits 34 to 37 based on the comparison result of the phase comparison circuit 38, and outputs the video signal with a predetermined time delay. The variable phase adjustment circuit 39 receives the video signal output from the switch 40, adjusts the phase difference of the video signal within 1H with respect to the reference signal, and outputs this video signal to the output terminal 32 of the phase adjustment unit 5. I do. The switching device 7 in FIG.
The switching is performed, so-called blanking switching is performed.
Synchronization signal is supplied to the switch as switching timing information
However, illustration is omitted. Also, the signal is switched
It is necessary to change the phase adjustment in 1H units depending on
Is determined by the line number detected after signal switching.
It is. Phase adjustment is limited to the vertical blanking period.
There is no particular need to set it, and it is sufficient to immediately respond to signal switching.
Therefore, the line number detected after signal switching and the reference signal
The phase difference from the signal is determined, and the phase can be adjusted.
From switching to the end of vertical blanking until the video starts
If the period is 12H, adjust the phase by about 5H vertically.
Obviously, it can be completed within the blanking period.
In addition, whether or not the phase can be adjusted is determined immediately.
Can be determined.

The mixing amplifier 6 receives the video signal output from the phase adjuster 5, mixes and amplifies the video signal, and outputs it to the output terminal 3.

In this embodiment, a data signal which changes every horizontal cycle of the video signal and is reset at the vertical cycle is added to the video signal on the input side of the switch 7. In this case, since the data signal corresponds to the scanning line number of the video signal, the scanning line number of the video signal can be easily determined on the output side of the switch 7. Therefore, in the phase adjustment unit 5 on the output side of the switch 7, the data signal can be separated from the video signal, and the phase of the video signal can be adjusted in units of the horizontal cycle (1H) according to the data signal. Thus, a video signal whose phase is shifted by several H can be adjusted at a high speed (for example, within 12H), and thus the phase adjustment can be completed within the vertical blanking period of the video signal.

In this embodiment, a 3-bit data signal can be added to the video signal by the insert circuit 4 on the input side of the switch 7. Further, the data signal added to the video signal during the horizontal blanking period can be easily deleted by the phase adjustment unit 5, and the synchronization signal can be replaced.

[0020]

As described above, according to the present invention, the data signal counted at each horizontal cycle of the video signal and reset at the vertical cycle is added to the horizontal blanking period of the video signal. Accordingly, the phase of the video signal can be adjusted in horizontal cycle units. Thus, the phase adjustment can be completed within the vertical blanking period of the video signal.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a video switcher including a phase adjustment device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an insert circuit of the phase adjustment device according to the embodiment.

FIG. 3 is a block diagram illustrating a phase adjustment unit of the phase adjustment device according to the embodiment.

FIG. 4 is a block diagram showing a video switcher provided with a conventional phase adjustment device.

[Explanation of symbols]

1, 21, 31: input terminal 2, 3 3 : reference signal input terminal 3, 22, 3 2 : output terminal 4: insert circuit 5: phase adjuster 6: mixed amplifier 7, 40: switch 23: synchronous data generation Circuit 24: Signal addition unit 34, 35, 36, 37: Delay circuit 38: Phase comparison circuit 39: Variable phase adjustment circuit

Claims (1)

(57) [Claims] A counter that counts each horizontal cycle of the video signal and resets the vertical cycle of the video signal; and a signal addition unit that adds a line number data signal from the counter to a horizontal blanking period of the video signal. , Signal addition
Switching at the timing of the vertical blanking receives a signal from the Department
A switching device for switching, the video signal output from the switching device,
Separate line number data signal and respond to phase difference with reference signal
And a phase adjustment unit for adjusting the phase in the same manner.
Line number included in the data signal
A comparison circuit that compares the reference signal with
Delays the video signal up to 12H based on the comparison result
A delay circuit for causing the phase adjustment to be performed.