JPH01194591A - Video signal processor - Google Patents

Abstract

PURPOSE:To enable the low cost of a device and the image of high quality to be simultaneously attained by making the adjustment of the whole device unnecessary and building the whole circuits of the device in the semiconductor integrated circuit of one chip. CONSTITUTION:By previously storing digital composite video signal data corresponding to digital RGB color data, the circuit is scaled down and simplified. Then, as the data is lastly converted to analogue data by a single digital- analogue conversion device 8, the adjustment is made to be entirely unnecessary. Therefore, the circuit can be made on the semiconductor integrated circuit of one chip. Thus, the composite video signal of high quality which is suitable for mass production and can cost down the device can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention displays image information expressed in digital RGB color data output from a Bernal combination coater system or a video game machine on a CRT display device. The present invention relates to a video signal processing device that converts into a composite video signal (for example, NTSC system or PAL system) for this purpose.

[Conventional technology]

In recent years, personal computer systems and video game consoles have become increasingly contradictory. Since these are realized exclusively by digital integrated circuits, image information is also expressed as digital RGB color data within the system. In order to configure a system at low cost, it is essential to use a conventional television receiver as a CRT display device. Therefore, it is essential to use a conventional television receiver as a CRT display device. Image information must be output as a composite video signal using the PAL system (in Europe), and therefore a video signal processing device that converts digital RGB color data into a composite video signal is required. FIG. 8 shows a configuration diagram of a conventional video signal processing device. conventionally,
Using a matrix conversion device, digital RGB color data is converted into digital Y, in which the luminance signal is expressed as a digital value.
data, digital R-Y data in which the red difference signal is expressed as a digital value, and digital B-Y data in which the blue difference signal is expressed in digital values. Digital B-Y data is converted into analog R-Y data and analog B-Y data by three independent digital-to-analog converters, and the analog R-Y data and analog B-Y data are By performing balanced modulation using color subcarriers whose phases differ by 90 degrees, and mixing anlog Y data, balanced modulated R-Y data and B-Y data, and a separately generated composite synchronization signal and burst signal. , a composite video signal was obtained.

The composite video signal of the NTSC or PAL system consists of a luminance signal, a color difference signal, a horizontal/vertical composite synchronization signal, and a color bust signal.Of these, the color difference signal and the luminance signal are the key to high image quality. . However, the color difference signal is
Color subcarrier (3.58MHz in NTSC system, PA
In the L method, the amplitude of the color subcarrier is It was not possible to obtain a high-quality composite video signal without finely adjusting the phase and phase using a mixing circuit.

On the other hand, in order to reduce the cost of the device, it is necessary to incorporate all the circuits into a single-chip semiconductor integrated circuit, but in this case, 1711 adjustment of the mixed circuit becomes impossible. Therefore, it has been impossible to achieve low cost and high quality images at the same time.

[Problem to be solved by the invention]

The present invention eliminates all the drawbacks of the conventional methods as described above, and eliminates the need for adjustment of the entire video signal processing device, realizing a single-chip semiconductor integrated circuit and achieving high quality at low cost. The purpose is to obtain a composite video signal with a high quality.

[Means to solve the problem]

The video signal processing device of the present invention converts RGB color data expressed in digital values into analog values consisting of each component of a luminance signal component, a color difference signal component, a horizontal synchronization signal, a vertical synchronization signal, and a color bar. In a device that converts and outputs a composite video signal expressed by a color subcarrier, one period of a color subcarrier is divided into a plurality of time intervals, and RGB color data expressed by the digital value is converted to the analog signal for each time interval. A semiconductor integrated circuit in which a composite video signal expressed as a digital value corresponding to the RGB color data expressed as the digital value at each time interval is stored in advance when converting into a composite video signal expressed as a value. means for converting the composite video signal expressed by the digital value,
The present invention is characterized in that means for converting the digital-to-analog converter into a composite video signal expressed by the analog value is provided on a semiconductor integrated circuit on the same chip.

〔Example〕

FIGS. 1 and 3 are block diagrams of a video signal processing device that is an embodiment of the present invention.
"r" SC is converted into a convoluted l-signal. FIG. 1 is a block diagram of an apparatus for carrying out a first signal processing method, and FIG. 3 is a block diagram of an apparatus for carrying out a second signal processing method. Digital RGB color data is 3 bits each, total 9
Bit set.

Therefore, it is possible to express 512 colors. The table below shows 512 digital RGB color data. Among the luminance signal component and color difference signal component data, representative 50 color data are shown.

The representative 50 colors were black + 7 colors x 7 gradations.

In the power level diagram, set the 6-bed scale level (black level) at the time of color par output to 10, and set the synchronization: brightness (black - white) to 2:5, and set the white level to 35. Full scale. The brightness levels of these color pars correspond to the maximum output of each color in the table above. Also,
The dotted lines indicate the upper and lower limits of the level when two digitally modulated color difference signals are added.

From this, FIG. 1 shows the first and second signal processing methods.
Digital RGB color data input terminals 1.2 in FIG.
3 will be explained using the case where digital values (7, 0, 7) are input. At this time, magenta is being output.

The first signal processing method shown in FIG.
In the C method, one period of 3.58 MHz) is divided into 12 equal intervals, and data in eight states (■ to ■) are sequentially output from the semiconductor memory device 10 depending on the timing. The luminance signal component and color difference signal component data for magenta (7,0,7) are (20,1
3,7). Moreover, the balanced modulation data for the eight data output states (■-■) is calculated as follows.

■゛y + (RY) 20±13
=33■Y+(RY)+(B-Y)20+13+7
=40■Y +(B-Y)20
+7 =27■Y-(RY)+(B-Y)20-1
3+7 =14■Y-IR-Y) 2
0-13 =7■Y -(RY)-(B-Y)
20-13-7 = 0■Y -(B-
Y)20 -7 =13■Y+(R-'/)
-(B-Y) 20+13-7 = 26 Although the semiconductor recording device 10 uses a read-only memory (ROM), it can also be used as a read-write memory (RAM). , the data obtained by the calculations of (1) to (2) above are stored in the semiconductor storage device 10 in advance, and the 9-frequency divider circuit 12 divides one period (1/1) of the color subcarrier using 6 times fsc. f s
c) is divided into 12 at equal intervals to create 12 clock pulses as shown in Figure 2 A to A. These 12 clock pulses turn on each of the 12 switches of the data selector 11. For the clock pulse in Figure 2A, only the switch in A of the data selector 11 is
High h'''C'' is turned on, and during the High period, only the data of ■ is output from the semiconductor memory device 10.

For one tarock pulse, only the data (2) is output, and subsequently for the other clock pulse, only the data (2) is output. As described above, for one set of digital input data, data in eight states from ■ to ■ are continuously output as a digital video signal, which is converted by one digital-to-analog converter 8 to produce a composite video signal. It has gained. FIG. 6 is a composite video signal diagram of 8-state output for magenta (7, 0, 7), and is an enlarged view of FIG. 5 when magenta is output.

Next, the second signal processing method shown in FIG. Data in four states are sequentially output from the semiconductor memory device 13.

This is a simplified version of the first processing method. The luminance signal component and color difference signal component data for magenta (7,0,7) are (20,1
3, 7), and the balanced modulation data for the four data output states ■' to ■' are calculated as follows.

■'Y+(R-YJ +(B-Y) 20+13+7
=40■'Y-In-Y) +(B-Y) 20-1
3+7 =14■'Y-(ll-Y) -18-Y)
20-13-7 =0■'Y+(RY) -(B-
Y) 2013-7 = 2 (i) The data obtained by the calculations in the previous steps ■' to ■' for all 512 colors is stored in advance in the semiconductor storage device 13.The frequency dividing circuit 15 , one period (1/f9c) of the color subcarrier is divided into four at equal intervals using double fsc or quadruple fsc to create the four clock pulses shown in Fig. These four types of clock pulses turn on the four switches of the data selector 14.In response to the tarock pulse shown in Fig. 4A, the switch A of the data selector 14 turns ON at High. Te, H
During the ``high'' period, only the data ``■'' is output from the semiconductor memory device 13. For the clock pulse of A,
For one set of digital input data, such as 0 or more, only the data of ■' is output, the data of four states of ■' to ■' are continuously outputted as a digital video signal, and one digital It is converted by an analog converter 8 to obtain a composite video signal. FIG. 7 is a composite video signal diagram of four-state output for magenta (7, 0, 7), and is an enlarged view of FIG. 5 when magenta is output.

Note that FIG. 1 shows the input terminal 4 of the semiconductor recording device in FIG.
．． Reference numerals 5 and 6 denote a blanking signal input terminal, a horizontal/vertical composite synchronization signal input terminal, and a color burst signal input terminal, respectively, and data corresponding to the levels of these signals are also output from the semiconductor storage device 9. In this way, since the digital composite video signal data corresponding to the digital RGB color data is stored in advance in the semiconductor storage device, the circuit is miniaturized and simplified, and finally, the digital composite video signal data corresponding to the digital RGB color data is Since it is converted into data, a high quality composite video signal can be obtained even though no adjustment is required.

〔Effect of the invention〕

As described above, according to the present invention, there are no parts that require adjustment, and since it is constructed using only conventional MOS digital circuit technology, it can be created on a single-chip semiconductor integrated circuit. becomes possible. Therefore, ・No adjustment is required. ・Suitable for mass production and low cost. ・High quality composite video signals can be obtained. ・Each circuit can be designed to be optimized, resulting in high speed and low consumption. Extremely large effects such as improved power efficiency can be obtained.

[Brief explanation of the drawing]

1 and 3 are block diagrams in which an NTSC video signal processing device, which is an embodiment of the present invention, is realized using a one-chip semiconductor integrated circuit. The figure is a configuration diagram of four-state processing. FIG. 2 is a timing waveform diagram of 12 types of clock pulses for 8-state processing, and 12 switches of the data selector are turned ON in response to the 12 types of clock pulses A to A. FIG. 6 is a composite video signal diagram of magenta (7, 0, 7) in 8-state processing, and is an enlarged diagram when magenta is output. FIG. 4 is a timing waveform diagram of four types of tarock pulses for four-state processing, and four switches of the data selector are respectively turned on in response to four types of clock pulses of this AN. FIG. 7 is a composite video signal diagram of magenta (7, 0, 7) in four-state processing, and is an enlarged diagram when magenta is output. FIG. 5 is an output level diagram of the composite video signal in this embodiment. FIG. 8 is a block diagram of a conventional video signal processing device. 1...Digital R color data input terminal 2...Digital G color data input terminal 3...Digital B color data input terminal 4...Blanking signal input terminal 5...Composite synchronization signal input terminal 6. . . . Color burst signal input terminal 7 . . Color subcarrier input terminal 8 . . . Digital-to-analog converter 9 . - Frequency divider circuit 13...Semiconductor storage device 14...Data selector 15...Frequency divider circuit 31...Synchronization signal input terminal 32...Digital R color data input terminal 33...
Digital G color data input terminal 34...Digital B
Color data input terminal 35...Clock signal input terminal 36...Matrix conversion circuit 37...Control signal generation circuit 38...Digital burst signal generation circuit 39...Digital-to-analog conversion device 40...Digital Balanced modulation circuit 41...Digital balanced modulation circuit 42...Composite video signal synthesis circuit 43...Composite video signal output terminal. 44... Digital Y signal 45... Digital RY signal 46... Digital B-Y signal 47... Burst signal control 1 word 48... Carrier wave signal for burst generation 49... R- Y balanced modulation carrier wave signal 50...R-Y balanced modulation carrier wave signal Applicant: Seiko Epson Corporation Figure 1 Figure 3 Figure 1

Claims (1)

[Claims] Converts RGB color data expressed in digital values to a composite video signal expressed in analog values, which consists of each component of a luminance signal component, a color difference signal component, a horizontal synchronization signal, a vertical synchronization signal, and a color burst signal, and outputs it. In the device,
When dividing one period of the color subcarrier into a plurality of time intervals and converting the RGB color data expressed by the digital values into a composite video signal expressed by the analog values for each time interval, each period is divided into a plurality of time intervals. means for performing conversion by a semiconductor integrated circuit in which a composite video signal expressed in digital values corresponding to the RGB color data expressed in the digital values at time intervals is stored; and a composite image expressed in the digital values; A video signal processing device, comprising means for converting a signal into a composite video signal expressed by the analog value using a digital-to-analog conversion device, on a semiconductor integrated circuit on the same chip.