JPH07240857A - Data slicer - Google Patents

Abstract

PURPOSE:To realize the data slicer in which comparate processing is applied in common to data whose standards differ from each other. CONSTITUTION:A pedestal clamp circuit 1 clamps a pedestal level in a video signal at a potential VC and a specific line selection gate circuit 2 extracts various data (equivalent pulse) superimposed for a blanking period of a video signal subject to pedestal clamp in response to a line selection pulse signal LS. A peak hold circuit 3 generates an intermediate potential between a peak hold level of the extracted equivalent pulse and the pedestal level clamped to the potential VC. Then a comparator 4 comparates the intermediate potential with an intermediate potential (slice level) generated from an output of the pedestal clamp circuit 1. Thus, as a result, data of various standards superimposed for the blanking period are located to various data being an object of line selection pulse to attain the comparate processing by a common circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data slicer suitable for use in, for example, extracting a character signal superimposed on a vertical blanking period in a video signal.

[0002]

2. Description of the Related Art As is well known, in recent years, a character signal for character multiplex broadcasting, a closed caption signal for displaying subtitles, or an image receiving screen in a vertical blanking period of a video signal (for example, NTSC composite signal). A wide ID signal or the like for determining the aspect ratio is superimposed.
The data formats / standards of these various signals are not standardized. For example, in the wide ID signal, the H (high) level of the signal is "70IRE" and the L (low) level is "0IRE". For closed caption signals, H level is "50IRE" and L level is "0IR".
"E".

[0003]

Now, in order to extract various signals to be superimposed on the video signal in this way, they are compared at a predetermined slice level based on the data format / standard defined for each signal. To form a digital signal. Therefore, in a television receiver including a data slicer that performs such a comparison process, it is necessary to mount a plurality of data slicers so as to correspond to each signal, which is also a factor of increasing the product cost. Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a data slicer that can perform common processing commonly on data of different standards.

[0004]

In order to achieve the above object, in the present invention, the pedestal level in the video signal is set to the first level.
Pedestal clamp means for clamping to the potential of the pedestal, a selection means for extracting a plurality of equivalent pulses superimposed in the blanking period of the pedestal clamped video signal according to a selection signal supplied from the outside, and the selection means. And a pedestal clamp, which slice level generating means generates a slice level corresponding to an intermediate potential between the peak hold level and the first potential while peak-holding the equivalent pulse selected by Comparing the output of the means at the slice level,
And a comparison means for outputting the comparison result at the second potential.

[0005]

According to the present invention, the pedestal clamp means clamps the pedestal level in the video signal to the first potential, and the selection means various data superimposed during the blanking period of the pedestal clamped video signal ( Equivalent pulse). The slice level generating means generates an intermediate potential between the peak hold level of the extracted equivalent pulse and the pedestal level clamped to the first potential. And
The comparison means compares the output of the pedestal clamp means at the slice level, and outputs the comparison result at the second potential.
As a result, the data of various standards superimposed during the blanking period can be processed by the common circuit, and the input level fluctuation of the video signal can be dealt with.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a data slicer according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a pedestal clamp circuit that clamps the pedestal level of a video signal on which various signals (character signal or closed caption signal) are superimposed in the vertical blanking period VBL to the potential VC and outputs the pedestal clamp circuit. That is, the clamp circuit 1 clamps the vertical blanking signal in the video signal supplied from the outside to the potential VC, and the specific line selection gate circuit 2 in the next stage and the non-inverting input terminal of the comparator 4 described later. Supply to.

The specific line selection gate circuit 2 selects and outputs various signals to be superimposed in the vertical blanking period VBL according to the line selection pulse signal LS. A peak hold circuit 3 detects the peak level of the signal output from the gate circuit 2 and outputs it as an H (high) level. Reference numeral 4 is a comparator. Comparator 4
A slice level divided by the resistors R ₁ and R ₂ to an intermediate level between the H level and the pedestal clamped level (potential VC) is applied to the inverting input terminal of the comparator 4. The outputs of the pedestal clamp circuit 1 supplied to the non-inverting input terminal side are compared according to the level, and a comparator output Dout is generated.

Next, the operation of the data slicer having the above configuration will be described. First, when the video signal shown in FIG. 2A is supplied, the pedestal level of the video signal is clamped to the potential VC and input to the specific line selection gate circuit 2. In FIG. 2A, HS indicates a horizontal sync signal. Next, when the line selection pulse signal LS shown in FIG. 2B is supplied to the gate circuit 2 in order to select various signals (character signal or caption signal) to be superimposed in the vertical blanking period VBL, The gate circuit 2 outputs various signals superimposed on the vertical blanking period VBL to the peak hold circuit 3.

The peak hold circuit 3 peak-holds various signals in the thus-gated vertical blanking period VBL and divides them into an intermediate level between the H level and the pedestal clamped level (potential VC). Convert to slice level. Then, as shown in FIG. 3C, the comparator 3 compares the pedestal clamped video signal at the slice level, and outputs various signals superimposed on the vertical blanking period VBL to, for example, a CMOS.
It generates a comparator output converted to a data level that can be directly used for digital signal processing such as level.

However, according to the above configuration, it is not necessary to perform the comparing process at the predetermined slice level based on the data standard defined for each signal as in the conventional case.
Since it is only necessary to pedestal clamp to the level required by each signal, it is possible to perform common processing even on data of different standards. Moreover, according to such a configuration, even when the input level of the video signal fluctuates, it is possible to always perform constant and stable comparison processing.

[0011]

According to the present invention, the pedestal clamp means clamps the pedestal level in the video signal to the first potential and the selection means superimposes during the blanking period of the pedestal clamped video signal. Extract the data (equivalent pulse). The slice level generating means generates an intermediate potential between the peak hold level of the extracted equivalent pulse and the pedestal level clamped to the first potential. Then, the comparison means compares the output of the pedestal clamp means at the slice level and outputs the comparison result at the second potential, so that the data of various standards superimposed during the blanking period are compared in the common circuit. In addition, stable comparator processing can be realized even when the input level of the video signal changes.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a data slicer according to an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the embodiment.

[Explanation of symbols]

 1 Pedestal clamp circuit 2 Specific line selection gate circuit 3 Peak hold circuit 4 Comparator

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[Procedure amendment]

[Submission date] July 4, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

Now, in order to extract various signals to be superimposed on the video signal in this way, they are compared at a predetermined slice level based on the data format / standard defined for each signal. To form a digital signal. Therefore, in a television receiver equipped with a data slicer that performs such comparison processing, the slice level of each signal must be adjusted so as to correspond to each signal.
It is necessary to mount a plurality of data slicers set to, which also causes a high product cost. Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a data slicer that can perform common processing commonly on data of different standards.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

According to the present invention, the pedestal clamp means clamps the pedestal level in the video signal to the first potential, and the selection means various data superimposed during the blanking period of the pedestal clamped video signal ( Equivalent pulse). The slice level generating means generates an intermediate potential between the peak hold level of the extracted equivalent pulse and the pedestal level clamped to the first potential. And
The comparison means compares the output of the pedestal clamp means at the slice level, and outputs the comparison result at the second potential.
As a result, the data of various standards that are superimposed during the blanking period can correspond the extraction timing of the selection means to the standard.
Therefore , the common circuit can perform the comparison process, and the input level fluctuation of the video signal can be dealt with.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a data slicer according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a pedestal clamp circuit that clamps the pedestal level of a video signal on which various signals (character signal or closed caption signal) are superimposed in the vertical blanking period VBL to a potential VC and outputs the pedestal clamp circuit. That is, this clamp circuit 1 is used for the pedestal in the video signal supplied from the outside.
The level is clamped to the potential VC and supplied to the specific line selection gate circuit 2 in the next stage and the non-inverting input terminal of the comparator 4 described later.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007] specific line selection gate circuit 2, vertical blanking interval VBL Noah according to the line selection pulse signal LS
One of various signals to be superimposed on the selected line is selected and output. A peak hold circuit 3 detects the peak level of the signal output from the gate circuit 2,
This is output as H (high) level. Reference numeral 4 is a comparator. A slice level divided by the resistors R ₁ and R ₂ into an intermediate level between the H level and the pedestal clamped level (potential VC) is applied to the inverting input terminal of the comparator 4. The outputs of the pedestal clamp circuit 1 supplied to the non-inverting input terminal side are compared according to the slice level, and a comparator output Dout is generated.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Next, the operation of the data slicer having the above configuration will be described. First, when the video signal shown in FIG. 2A is supplied, the pedestal level of the video signal is clamped to the potential VC and input to the specific line selection gate circuit 2. In FIG. 2A, HS indicates a horizontal sync signal. Next, the gate circuit 2 is supplied with the line selection pulse signal LS shown in FIG. 2B to select one of various signals (character signal or caption signal ) superimposed in the vertical blanking period VBL. Then, the gate circuit 2 outputs various line-selected signals to the peak hold circuit 3.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009] Peak-hold circuit 3, thus various signals in the gate by a vertical blanking interval VBL and peak hold, which was divided in the middle level of the pedestal clamped level (potential VC) as H level Convert to slice level. Then, as shown in FIG. 3C, the comparator 3 compares the pedestal clamped video signal at the slice level, and various signals superimposed on the vertical blanking period VBL are, for example, CMO.
A comparator output converted to a data level that can be directly used for digital signal processing such as S level is generated.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

However, according to the above configuration, it is not necessary to perform the comparing process at the predetermined slice level based on the data standard defined for each signal as in the conventional case.
Since the pedestal clamp may be performed at any level, it is possible to commonly perform the comparing process on the data having different standards. Moreover, according to such a configuration, even when the input level of the video signal changes,
It is possible to perform constant and stable comparator processing.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

According to the present invention, the pedestal clamp means clamps the pedestal level in the video signal to the first potential and the selection means superimposes during the blanking period of the pedestal clamped video signal. Extract the data (equivalent pulse). The slice level generating means generates an intermediate potential between the peak hold level of the extracted equivalent pulse and the pedestal level clamped to the first potential. Then, the comparison means compares the output of the pedestal clamp means at the slice level and outputs the comparison result at the second potential, so that the data of various standards superimposed during the blanking period changes the timing of the selection means. By doing so, it is possible to perform the comparison process in the common circuit, and in addition, the stable comparison process can be realized even when the input level of the video signal changes.

Claims (1)

[Claims] 1. A pedestal clamp means for clamping a pedestal level in a video signal to a first potential, and a plurality of equivalent pulses which are superimposed during a blanking period of a pedestal clamped video signal are externally supplied. Selection means for extracting in accordance with the selection signal, peak hold of the equivalent pulse selected by the selection means to detect a peak hold level, and corresponding to an intermediate potential between the peak hold level and the first potential. A data slicer comprising: a slice level generating means for generating a slice level; and a comparing means for comparing an output of the pedestal clamp means at the slice level and outputting a comparison result at a second potential.