JPH031664A - Ghost elimination device - Google Patents

Abstract

PURPOSE:To obtain a ghost elimination device whose ghost eliminating capability is always maximized by controlling the phase of a sampling clock so as to always maximize the level of a peak point of a ghost signal. CONSTITUTION:The device consists of an A/D converter 5, a generating circuit 3 for a sampling clock SK and a peak detection circuit 7. Through the constitution above, a clock phase control data is outputted from a controller 9 and a TV signal is sampled with a clock SK having a phase selected by the data to extract a peak point data of a GCR signal. The data is stored in a memory in the controller 9. Then a clock phase control data selecting a different clock phase is outputted from the controller 9 and similarly the peak point data is extracted. The processing above is executed for all clock phases and the control data selecting the clock phase with the largest peak point data is outputted from the controller 9. Thus, the GCR signal is subjected to A/D conversion with a desired clock SK at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a ghost removal device suitable for application to received signals of television receivers, etc. (New Technology) Currently, with the trend toward higher picture quality on televisions, it is now necessary for broadcasting stations to send out a standard signal for ghost removal (GCR signal) once, so that ghost removal can be easily performed on the receiver side. is being considered.

Ghost removal reference signal (G CR
No. 18) includes a 5in(x)/X pulse shown in FIG. 3A and a 5in(x)/x lever not shown in FIG. 3B.

By differentiating the 5in(x)/y lever, 5in(
y)/y pulse is obtained, and on the receiving IB side, 5in(x)/y pulse is obtained.
Use after xX pulse conversion.

The peak point of the OCR signal refers to the point of maximum amplitude in the 5in(X)/xX pulse state, and this peak point serves as the reference point in ghost removal. Note that the reference OCR signal generated inside the ghost removal device will be referred to as an RGCR signal below.

The ghost removal device extracts the GCR signal sent out by the broadcasting station on the reception side, equalizes the waveform of the extracted OCR signal into an RGCR signal held in the coast removal device, and performs ghost i removal.

``Problems to be Solved by the Invention'' The RGCR signal in the ghost removal device is stored in a ROM or the like as data sampled at peak points as shown in FIG. 4.

In such a case, there will be no problem if the received GCRjN signal is sampled almost at the peak point as shown in the figure 8. It may be sampled like C or D.

This is because the sampling clock for A/D converting the OCR signal is locked to the color burst signal or the horizontal open signal, but the OCR signal has a phase difference between the color burst 1 word and the horizontal synchronization signal. Relationships are not managed. Therefore, the peak point of the OCR signal is not necessarily sampled. If sampling is performed as shown in B, C, or D in the figure, the ghost removal ability will be significantly degraded.

Therefore, the present invention takes these points into consideration and proposes a ghost removal device that can always maximize its ghost-me removal ability.

"Means for Solving the Problems" In order to solve the above problems, the present invention provides an A/D converter that A/D converts a reference signal for ghost removal, a sampling clock generation circuit supplied to the A/D converter, and a sampling clock generation circuit supplied to the A/D converter. , means for detecting the peak point position and the magnitude of the peak point of the ghost signal, and the phase of the sampling clock is controlled so that the magnitude of the peak point is maximized. be.

“Function” In this configuration, the ghost removal standard (No. 8-(OC
The magnitude of the peak point of the R signal is detected, and the phase of the sampling clock is selected so that the peak point is the largest.

Specifically, the sampling phase is sequentially changed, the magnitude of the peak point at each time is memorized, and the maximum modulus of the memorized peak point magnitude is determined as the phase of the sampling clock. A/D converts the OCR signal.

"Embodiment" Next, an embodiment of the present invention will be described with reference to the block diagram of FIG. 1.

In the figure, reference numeral 1 denotes an input terminal to which a television signal is supplied, and the manually inputted television signal is supplied to a synchronization separation circuit 2 and an A/D converter 5. The synchronization separation circuit 2 generates the color sub-IQW transmission wave fsc and performs horizontal synchronization separation, and the next clock generation t'r-circuit 3 generates the sampling clock SK by PLL using the horizontal synchronization signal or the color subcarrier. do.

Sampling clock S K is clock phase selection circuit 4
Based on the control data from the controller 9, the clock phase is changed by the necessary amount.

The sampling clock SK that has undergone the necessary amount of phase change in this way is co-supplied to the A/D converter 5)\/D
From the television signal digitized by the converter 5, only the OCR signal is extracted by the OCR extraction circuit 6, and the peak of G CRIi is detected by the peak detection circuit 7.

From the peak-detected OCR data, peak point data (size) is extracted by a peak point data extraction circuit 8 and is supplied to a controller 9 . The controller 9 can be composed of a microprocessor or the like, and data for controlling the phase of the sampling clock SH is supplied to the clock phase advance Y&4.

The clock phase selection tR circuit 4ζ can be constructed using a plurality of delay circuits, for example, as shown in FIG.

In the figure, lO is a clock input terminal from the clock generation circuit 3, and 11 is 1/n of the clock frequency (1/n in this example).
78) is the time delay time Y3.

12 is a multiplexer that selects one from 11 types (8 types in this example). The phase of the sampling clock SK changes depending on which delay circuit 11 is selected.

Next, the operation of this example will be explained.

First, a certain clock phase control data is output from the controller 9, and a television signal is sampled using a sampling clock SK having a certain phase selected by the data to extract peak point data of a GCR signal. The peak point data is stored in a memory built into the controller 9.

Next, the controller 9 outputs clock phase advantage data for selecting the first different clock position, and similarly extracts peak point data. This is executed for all selectable clock phases, and finally the controller 9 outputs control data for selecting the clock phase with the largest peak point data, that is, the clock phase that can sample the point closest to the peak of the GCRli signal.

In this way, the GCRI word can be A/D converted using the sampling clock SK that always provides the maximum peak point data.

"Effects of the Invention" As explained above, according to the present invention, the peak point of the GCR signal is always sampled, so that the ghost removal ability can always be maximized. Therefore,
Improved ghost removal performance.

The image after ghost removal becomes high quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a clock phase selection circuit, and FIG. 3 is a waveform diagram showing a ghost removal standard (-11 of No. 3). Figure 4 is a diagram showing changes in GCR data depending on the sampling phase. 4th race, 5th race, 6th, 7th, 8th race - Sampling clock S K generation circuit - Clock position selection circuit - A/D converter - GCR Signal extraction circuit, peak detection circuit, peak point data extraction circuit 9φ...Controller Patent Applicant Sharp Corporation Agent Kunio Yamaguchi Figure 1 Figure 2 Ghost Removal 1 & Quasi Signal (GCR Signal) Figure 4 Changes in CrCR signal due to salep link

Claims (1)

[Claims] (1) A/D converting the reference signal for ghost removal
a converter, a sampling clock generation circuit supplied to the converter, and means for detecting the peak point position and magnitude of the peak point of the ghost signal; A ghost removal device characterized by controlling the phase of a sampling clock.