JPH0614760B2 - Color signal phase adjuster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a color for a luminance signal of a composite video signal in order to make the phase of a color signal continuous when a screen composed of a plurality of videos is synthesized on a TV screen. The present invention relates to a color signal phase adjuster capable of arbitrarily changing the phase of a signal.

[Conventional technology]

The present applicant demodulates the composite video signal to the baseband and performs necessary processing when synthesizing a single screen or creating a reduced screen using two or more composite video signals, and then again desires. Developed a composite video signal processing device that can continuously change the phase of the color signal by arbitrarily changing the phase of the color signal with respect to the luminance signal without performing the troublesome processing of modulating into the composite video signal having the phase of Already Japanese patent application Sho 63
-134330 has been filed.

The outline will be described. The composite video signal is sampled by a clock signal having a frequency N times that of the color subcarrier of the composite video signal, and every N sample values are sampled and an appropriate calculation is performed between these sample values. After that, the D / A conversion is performed to arbitrarily change the phase of the color signal with respect to the luminance signal, and the phase of the color signal can be changed without demodulating and modulating the composite video signal. It's a breakthrough.

[Problems to be Solved by the Invention]

However, when changing the phase of the color signal, this device requires the arithmetic operation of weighting the sample values to correct the level of the luminance signal and performing the arithmetic mean. It had the drawback of being limited.

An object of the present invention is to improve the drawbacks of the conventional device, and to provide a color signal phase adjusting device capable of arbitrarily changing the phase of the color signal without impairing the degree of freedom of the circuit. .

[Means for Solving the Problems]

In order to achieve the above object, the phase adjusting device for a color signal according to claim 1 of the present invention generates a clock signal which is synchronized with a color subcarrier of a composite video signal and has a frequency N times that thereof. A clock generator, a separator for separating the composite video signal into a luminance signal and a chrominance signal, and an A / for sampling the chrominance signal separated by the separator by the clock signal
A D converter, a delay device that sequentially extracts sample values obtained by the A / D converter as N types of signals having different phases, and a changeover switch that selects one of the N types of delayed signals output from the delay device, The output of the changeover switch is D / A
And a D / A converter for converting the new color signal to have a different phase from the color signal.

The color signal phase adjuster according to the second aspect is a clock generator that generates a clock signal having a frequency N times that of the color subcarrier of the composite video signal in synchronization with the composite video signal. , An A / D converter that samples the sample value, a separator that separates the sample value obtained by the A / D converter into a luminance signal component and a chrominance signal component, and a color signal component of the sample value separated by the separator by N A delay device that sequentially extracts signals of different kinds of phases, and a changeover switch that selects one from N kinds of delayed signals output from the delay device,
And a D / A converter for D / A converting the output of the changeover switch to generate a new color signal having a phase different from that of the color signal.

[Action]

The color signal separated from the composite video signal by the clock signal is sampled, or the color signal component is separated after sampling the composite video signal, and the sampled values are sequentially taken out as N types of signals having different phases. , A new color signal having a phase different from that of the original color signal is obtained by selecting one of the changeover switches and performing D / A conversion.

〔Example〕

A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram thereof, and FIG. 2 is a signal waveform diagram of each part thereof.

The color signal phase adjusting apparatus includes a clock generator 1, a separator 2, an A / D converter 3, a delay device 4, a changeover switch 5 and a D / A converter 6, and outputs a composite video signal input from an input terminal I. The phase of the color signal with respect to the luminance signal is changed and output to the output terminal O.

The clock generator 1 generates a clock signal having a frequency 4fsc which is four times the frequency fsc in synchronization with the color subcarrier of the composite video signal input from the input terminal I. The separator 2 separates the composite video signal into a luminance signal and a color signal, and sends the color signal to the A / D converter 3. A / D converter 3
In this case, this color signal is sampled by the clock signal,
This sample value is sent to the delay device 4. The delay device 4 is composed of three stages of shift registers 4a, 4b and 4c, and sends the input sample value to each of the fixed terminals 5a to 5d of the changeover switch 5 as four kinds of signals shifted by one clock. In the changeover switch 5, by selecting any of the fixed terminals 5a to 5d, 4
One of the types of delayed signals is selected. The selection of fixed terminals is not always fixed, if necessary,
It can also be changed depending on the time. The signals (or a set thereof) selected in this way are converted into analog signals by the D / A converter 6 and then output to the output terminal O.

The output new color signal is combined with the previously separated luminance signal, if necessary, to form a composite video signal. The combination with the luminance signal may be performed before the D / A converter 6.

Next, the operation will be described with reference to FIG.

The composite video signal (a) input from the input terminal I is separated into a luminance signal (b) and a color signal (c) by the separator 2, and the color signal (c) is separated in the A / D converter 3. It is sampled by the clock signal and becomes a sampled value (d). This sampled value (d) is shifted by 1 clock by the delay unit 4
It is output as a type signal and sent to each fixed terminal 5a-5d of the changeover switch 5. That is, (d) is input to the fixed terminal 5a as it is, and delayed signals (e), (e), and (e) having different phases are input to the fixed terminals 5b, 5c, and 5d by one clock, respectively.

Now, since two composite video signals are used by half to compose one video, considering the case where the phase of the composite video signal with respect to the luminance signal is shifted by 180 degrees, one of the delay signals ( F) is selected and the delayed signal is converted into an analog signal by the D / A converter 6, the obtained new color signal (h) has a phase of 180 degrees compared to the original color signal (b). It will be delayed.

Actually, the clock signal used for the D / A conversion by the D / A converter 6 is a clock signal common to the two composite video signals in order to make the phases of the color signals of the two composite video signals have continuity. Since it is used, the signal may be different from the clock signal when sampling is performed by the A / D converter 3, so that when two or more composite video signals having different phases are combined, The phase of the signal can be continuous.

Further, when it is desired to reduce the composite video signal to 1/2, it is necessary to take out every other sample value and then compress the time axis to 1/2, so that the changeover switch 5 is sequentially operated by the clock signal. Switching, for example, at time T ₀ , fixed terminal 5a, at T ₂ , 5b, at T ₄ , 5c, T
_By switching 5d in ₆ and 5a in T ₈ and so on, the signal as shown in (i) can be obtained.
A desired color signal is obtained by compressing the time axis of this signal by half and then performing D / A conversion. At this time, the phase of a new color signal can be changed by appropriately changing the initial state of the fixed terminal to be selected.

FIGS. 3 and 4 are a block diagram of the second embodiment and an output signal waveform diagram of the A / D converter thereof.

The difference of this embodiment from the first embodiment is that the separator 2 is provided in the subsequent stage of the A / D converter 3.
Other configurations are exactly the same.

The composite video signal (a) input from the input terminal I is sampled as it is by the clock signal in the A / D converter 3, and this sampled value (nu) is supplied to the luminance signal component and the color signal in the separator 2. Separated into components. The color signal component (n) of this sampled value is the same as the sampled value (FIG. 2 (d)) obtained by sampling the color signal in the first embodiment, and therefore the subsequent operation is the first. This is exactly the same as the embodiment described above.

In the above embodiment, the frequency of the clock signal is set to 4 times the color subcarrier, but the frequency is not limited to this, and any setting of 2 times or more may be set. Absent. Also, in order to reduce the color signal band on a reduced screen,
A filter may be provided before the delay device 4.

〔The invention's effect〕

As described above, the phase adjustment device for a color signal of the present invention does not perform the troublesome process of demodulating the composite video signal to the baseband and again modulating the composite video signal to have a desired phase. The phase of the color signal can be arbitrarily changed, and the degree of freedom of the circuit is far increased as compared with the above-mentioned conventional apparatus of the present applicant, so that it is possible to easily obtain a high-quality screen.

[Brief description of drawings]

 1 ... Block diagram of first embodiment FIG. 2 ... Signal waveform diagram of each part thereof FIG. 3 ... Block diagram of second embodiment FIG. 4 ... Output signal waveform diagram of the A / D converter 1 ... Clock generator, 2 ... Separator 3 ... A / D converter, 4 ... Delay device 5 ... Changeover switch, 6 ... D / A converter

Claims (2)

[Claims] 1. A clock generator that generates a clock signal having a frequency N times that of a color subcarrier of a composite video signal; and (b) separating the composite video signal into a luminance signal and a chrominance signal. And (A) an A / D converter that samples the color signals separated by the separator using the clock signal, and (D) sample values obtained by the A / D converter have N types of different phases. (E) A changeover switch for selecting one of N kinds of delay signals output from the delayer, and (f) D / A conversion of the output of the changeover switch to obtain the color signal. A color signal phase adjusting device, comprising: a D / A converter that creates a new color signal having a different phase. 2. A clock generator for generating a clock signal having a frequency N times that of the color subcarrier of the composite video signal, and (b) A for sampling the composite video signal with the clock signal. A / D converter, (c) a separator that separates the sample value obtained by the A / D converter into a luminance signal component and a color signal component, and (d) a color signal component of the sample value that is separated by the separator. N
A delay device that sequentially extracts signals of different kinds of phases, (e) a changeover switch that selects one of N kinds of delay signals output from the delay device, and (f) D / A-converts the output of the changeover switch. And a D / A converter for producing a new color signal having a phase different from that of the color signal.