KR100348444B1 - Television standard signal converter - Google Patents

Abstract

PURPOSE: A television standard signal converter is provided to display two different television broadcasting signals on one screen without deteriorating picture quality. CONSTITUTION: A television standard signal converter includes the first field memory(100) for storing an input NTSC composite video signal in fields, an enable signal generator(110) for receiving a horizontal synchronous signal to allow the first field memory to read/write, the first line memory(120) for storing the signal output from the first field memory in lines, and an interpolation signal generator(140) for generating an interpolation signal. The converter further includes a line interpolator(130) for interpolating the output of the first line memory into the number of PAL lines according to the interpolation signal, the second field memory(150) for storing the signal output from the line converter in fields, the second line memory(160) for storing the signal output from the second field memory in lines, and a sampling rate converter(170) for accepting the output of the second line memory to convert the output signal into a PAL horizontal frequency to output a final PAL video signal.

Description

Standard Signal Inverter of TV

The present invention relates to a two-screen television that simultaneously displays two different broadcast signals on one screen, and particularly, converts a broadcast signal of a sub picture to a broadcast signal of a main picture in an area where a PAL broadcast signal and an NTSC broadcast signal exist simultaneously. The present invention relates to a standard signal converter of a television that displays two screens simultaneously without deterioration of image quality.

Conventionally, in a dual screen television which converts an NTSC broadcast signal into a PAL broadcast signal and displays it on a television screen simultaneously, in order to convert an NTSC broadcast signal into a PAL broadcast signal, it is divided into three directions: time direction, horizontal direction, and vertical direction. Although the processing is performed separately, there is a problem in that the image quality is degraded due to the clock speed conversion or interpolation effect in each step.

Therefore, in view of this problem, the present invention minimizes the degradation in image quality by simultaneously processing the NTSC broadcast signal using the same clock in the vertical and time conversion periods, and then performs horizontal conversion to display the entire frequency displayed on the screen in the PAL method. The purpose is to convert to.

Another object is to minimize the deterioration of gray matter by horizontally converting an NTSC broadcast signal to a PAL broadcast signal, and then vertically and timely, and the present invention having such a purpose will be described in detail.

As shown in FIG. 1, the standard signal switching device of the television of the present invention includes a first field memory (100) for storing an input NTSC system composite video signal (CVBS) in field units, and a horizontal synchronization signal (Hsync). A first signal for storing the enable signal generator 110 to read / write the first field memory 100 and a signal output from the first field memory 100 in line units. The number of lines of the PAL method according to the interpolation signal of the line memory 120, the interpolation signal generator 140 generating the line interpolation signal, and the output of the first line memory 120, and the interpolation signal generator 140. A line converting unit 130 for converting to a second field, a second field memory 150 for storing the line interpolated signal output from the line interpolation unit 130 in field units, and an output from the second field memory 150. A second line memory 160 for storing the signal in line units; The sampling rate converter 170 receives the output of the two-line memory 160 and converts the PAL signal to a horizontal frequency to output the final PAL video signal CIO.

The operation and effects of the present invention configured as described above will be described in detail.

When the write enable signal WEN is applied from the read / write signal generator 110, the first field memory 100 receives an NTSC composite video signal CVBS of 525 lines / 60 Hz 910 f _H and has a clock of 14.3 MHz. The read / write signal generator 110 receives the horizontal sync signal Hsync of the composite image signal CVBS, and stores the read / write enable signal according to the CLK1. REN) (WEN).

Subsequently, when the read enable signal REN is applied from the read / write signal generator 110, the first field memory 100 transmits field data stored by the clock CLK1 to the first line memory 120. ), And the first line memory 120 is applied to the first line memory 120 and stored in line units as a whole process for line conversion.

At this time, in order to convert the NTSC signal of 525 lines / 60 Hz into a PAL signal of 625 lines / 50 Hz, the field rate and the line rate must be simultaneously converted using a clock CLK1 of 14.3 MHz. 625 lines × 25 Hz = At 30 Hz = 520.83 Is set to 521 lines, the number of lines when writing to the first field memory 100 is 521 lines, and the read and write addresses of the first field memory 100 are reset every 12 fields. Will not occur.

In addition, if the above 625 lines are set to be 630 lines, the error of the decimal point may not occur even if the read and write addresses of the first field memory 100 are not reset.

Therefore, when converting an NTSC signal of 525 lines / 60 Hz to a PAL signal of 625 lines / 50 Hz, the line unit signal of the first line memory 120 is input to the line interpolator 130 to interpolate the signal generator 140. Line interpolation is performed by interpolating 5 lines into 6 lines by using interpolation data. However, the read enable state of the first field memory 100 is disabled once every 5 lines in order to convert 5 lines into 6 lines. Along with this, the write enable state of the first line memory 130 must also be disabled.

The line interpolator 13 receives the output of the line unit of the first line memory 120 and performs line interpolation by the interpolation signal of the interpolation signal generator 140. The interpolation coefficient input unit 130-1 is performed. ) Receives the coefficient K generated by the interpolation signal generator 140, and the line interpolation coefficient converter 130-2 receives data in field units output from the first field memory 100, and receives the line coefficient input unit. The subtractor 130-3 adds and outputs the outputs of the interpolation coefficient input unit 130-1 and the line interpolation coefficient converter 130-2 by subtracting one from the coefficient K of 130-1.

At this time, the interpolation signal output from the interpolation signal generator 140 is 1, 1/6, 2/6, 3/6, 4/6, 5/6, 1, By allowing the interpolation signal to change every line, the NTSC signal at 525 lines / 60 Hz is converted to 625 or 630 lines / 50 Hz without changing the clock.

The second field memory 150 receives the output of the line interpolator 130 and writes the data by the clock CLK1 of 14.3 MHz to store them in units of fields. The second field memory 150 stores them in units of lines. After reading and writing, the data is read by the clock CLK2 of 17.7 MHz and output to the sampling rate converter 170.

The sampling rate converter 170 needs about 5/4 more data to convert the horizontal frequency 910f _H in the NTSC system to 1135f _H in accordance with the PAL method, so that the line of the second line memory 160 The sampling rate is converted by the clock CLK2 of 17.7HHz by using the unit data. At this time, only 908 data among the 910 data inputted are used and the remaining two data are reset for each field to remove the time difference. The converter 179 outputs a PAL image signal CIO having 625 lines / 50Hz 1135f _H.

Therefore, this is performed by performing the vertical and time direction conversions first and then the horizontal direction conversions.

2 shows another embodiment of a standard signal switching apparatus of a television according to the present invention, as shown in FIG. 1, a first field memory 200 for storing an input NTSC system composite video signal (CVBS) in field units; An enable signal generator 210 which receives a horizontal sync signal Hsync to read / write the first field memory 200 and a signal output from the first field memory 200 in a line unit; The first line memory 220 to be stored as, the sampling rate converter 230 for converting the output of the first line memory 220 to the horizontal frequency of the PAL method and the horizontal synchronization signal (Hsymc) The line counter 250 is applied to count and generates a read enable signal REN for each line, and the output of the sampling rate converter 230 is stored and stored in units of fields. This is caused by the lead enable signal REN. A second field memory 240 for reading and outputting, a second line memory 260 for receiving the output of the second field memory 240 and storing them in line units, and generating an interpolation signal for generating a line interpolation signal And a line converter 270 for converting the output of the second line memory 260 to the number of lines of the PAL method according to the interpolation signal of the interpolation signal generator 280 and outputting the CIO. do.

In contrast to the case described with reference to FIG. 1, first, the horizontal direction conversion is performed first, followed by the vertical and time direction conversion. Each part is the same as the operation described with reference to FIG.

When the write enable signal WEN is applied from the read / write signal generator 210, the first field memory 200 receives an NTSC-type composite video signal (CVBS) of 525 lines / 60 Hz 910 f _H and has a clock of 14.3 MHz. By CLK1, this is stored in units of fields, and the first line memory 220 and the sampling rate converter 230 convert the field rate to 50 Hz and the sampling rate to 1135f _H.

At this time, when 910 data of 910f _H is read with a 14.3 MHz clock (CLK1) and the sampling rate is converted to 1135f _H , 505 lines per 50 Hz field and a corresponding decimal point error occur. The read / write address of the one-field memory 200 can be reset to remove it.

Accordingly, data of 505 lines / 50 Hz 1135f _H is stored in the second field memory 240, and the line interpolation unit 270 via the second line memory 260 shows only 500 lines as shown in FIG. Similarly, 5/4 line interpolation can be performed to obtain a PAL-type 625 line / 50 Hz 1135f _H video signal CIO.

At this time, the read clock RCLK of the second field memory 240 and the second line memory 260 is the second field memory 240 every four lines using the 17.7 MHz clock CLK2 which is a 4 fsc clock of the PAL signal. By disabling), you can create 5 lines with 4 lines, which allows you to generate 625 lines.

As described above, in the present invention, two different television broadcast signals exist (for example, the Middle East), the sub-picture broadcast signal is converted in the vertical direction and the time direction at the same time, and then the horizontal direction conversion or the horizontal direction conversion is performed first. After performing the conversion in the vertical direction and the time direction at the same time, it is converted into the broadcast signal of the main screen, so that all of them can be displayed on one screen without deterioration of image quality.

1 is a diagram showing an embodiment of a standard signal converter of a television of the present invention.

2 is a view showing another embodiment of the standard signal conversion apparatus of the present invention television.

3 is a diagram illustrating a method of converting a line interpolation signal of the interpolation signal generator of FIG.

** Explanation of symbols for main parts of drawing ***

100: first field memory 110: read / write signal generator

120: first line memory 130: line interpolation unit

130-1: line interpolation coefficient input unit 130-2: line interpolation coefficient conversion unit

140: interpolation signal generator 150: second field memory

160: second line memory 170: sampling rate converter

180: sampling counter

Claims (2)

A first field memory for storing an input NTSC composite video signal in field units, an enable signal generator for receiving a horizontal synchronization signal and allowing the first field memory to read / write the first field memory, and the first field The number of lines in the PAL method according to the first line memory for storing signals output from the memory in line units, the interpolation signal generator for generating line interpolation signals, and the output of the first line memory for interpolation signals. A line converting unit for converting to a second field; a second field memory for storing a line interpolated signal output from the line interpolation unit in a field unit; and a second line memory for storing a signal output from the second field memory in a line unit. And a sampling rate converter that receives the output of the second line memory and converts the horizontal frequency of the PAL method to output a final PAL video signal. TV standard signal converter, characterized in that consisting of A first field memory for storing an input NTSC composite video signal in field units, an enable signal generator for receiving a Suffolk synchronous signal and allowing the first field memory to read / write the first field memory, and the first field A first line memory for storing a signal output from the memory in line units, a sampling rate converter for receiving the output of the first line memory and converting the signal into a horizontal frequency of a PAL method, and receiving and counting A line counter for generating a read enable signal for each line, a second field memory receiving the output of the sampling rate converter and storing the result in a field unit, and then reading and outputting the read enable signal by the line counter; A second line memory that receives the output of the second read memory and stores it in line units, and a beam that generates a line interpolation signal And a line converting section for converting the inter-signal generating section and the output rate interpolating signal generating section of the second line memory into a PAL system according to the interpolation signal.