GB2134743A - Color display system - Google Patents
Color display system Download PDFInfo
- Publication number
- GB2134743A GB2134743A GB08334521A GB8334521A GB2134743A GB 2134743 A GB2134743 A GB 2134743A GB 08334521 A GB08334521 A GB 08334521A GB 8334521 A GB8334521 A GB 8334521A GB 2134743 A GB2134743 A GB 2134743A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signal
- color display
- carrier chrominance
- output
- luminance signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
- H04N9/641—Multi-purpose receivers, e.g. for auxiliary information
Abstract
A color display system comprises a signal generating device 30 and a color display monitoring receiver 31. The signal generating device 30 has a carrier chrominance signal generator 12, a luminance signal generator 13, a first output terminal 32 for directly producing an output carrier chrominance signal, and a second output terminal 33 for directly producing an output luminance signal. The color display monitoring receiver 31 has a first input terminal 34 coupled 36 with the first output terminal of the signal generating device and supplied with the output carrier chrominance signal, a second input terminal 35 coupled 37 with the second output terminal and supplied with the output luminance signal, a carrier chrominance signal demodulating circuit 19, and a display 21, 22 supplied with output signals of the carrier chrominance signal demodulating circuit 19 and the luminance signal processing circuit 20, for carrying out a color display. <IMAGE>
Description
SPECIFICATION
Color display system
The present invention generally relates to color display systems, and more particularly to a color display system which carries out the color display by supplying a color display signal from a color display signal generating device to a color display monitoring receiver.
Generally, a color display system is employed in a personal computer, a television game machine, and the like. In such a color display system, a color display signal for obtaining a color picture is generated from a color display signal generating device, and this color display signal is supplied to a color display monitoring receiver to carry out the color picture display.
Conventionally, an ordinary color television receiver was employed in most cases as the above color display monitoring receiver. For this reason, the conventional color display signal generating device was designed to generate a composite color video signal which is in conformance with a standard television system such as the NTSC system, for example. That is, the conventional color display signal generating device was designed to generate a multiplexed signal comprising a luminance signal which includes a composite synchronizing signal, and a carrier chrominance signal. The composite color video signal thus generated for the color display, was supplied to the color television receiver wherein the composite color video signal was separated into the luminance signal and the carrier chrominance signal.The separated luminance signal was supplied to a luminance signal processing circuit, and the separated carrier chrominance signal was supplied to a carrier chrominance signal demodulating circuit. Output signals of the luminance signal processing circuit and the carrier chrominance signal demodulating circuit, were supplied to a matrix circuit. An output signal of the matrix circuit was then supplied to a cathode ray tube (CRT) and displayed as a color picture.
As an example of a separating circuit for separating the luminance signal and the carrier chrominance signal in the color television receiver, there was a conventional separating circuit comprising a bandpass filter and a band suppression filter. The bandpass filter obtained the carrier chrominance signal in a frequency band which was +0.5 MHz about a chrominance subcarrier frequency. On the other hand, the band suppression filter eliminated the carrier chrominance signal from the input color display signal, and obtained the luminance signal. The carrier chrominance signal obtained in the bandpass filter was supplied to the carrier chrominance demodulating circuit, while the luminance signal obtained in the band suppression filter was supplied to the luminance signal processing circuit.
However, according to the above conventional separating circuit, a luminance signal component
remained within the carrier chrominance signal which was obtained in the bandpass filter.
Especially when the video information included parts where the luminance changed sharply such as the case where the picture contained characters and numerals, the high frequency component of the sharply changing parts was included within the carrier chrominance signal which was supplied to the chrominance signal demodulating circuit. Thus, this high frequency component was demodulated together with the chrominance signal in the carrier chrominance signal demodulating circuit. This demodulated high frequency component acted as a cross color interference and generated blur and the like in the color of the reproduced picture, and the picture quality was consequently deteriorated.In addition, the band suppression filter was designed to reduce the dot interference by providing a trap with respect to the chrominance subcarrier frequency, however, the high frequency component of the luminance signal was also attenuated by the provision of this trap, and the resolution accordingly became poor. Further, there was a disadvantage in that phenomena such as overshoot and ringing were generated in the sharply changing parts of the luminance signal due to the effects of the band suppression filter, and the picture quality became poor.
As another example of a conventional separating circuit for separating the luminance signal and the carrier chrominance signal in the color television receiver, there was a separating circuit having a comb filter construction. This separating circuit included a 1 H delay circuit for delaying the input composite color video signal by one horizontal scanning period, a subtracting circuit for carrying out a subtraction between the input composite color video signal and the output signal of the 1 H delay circuit to obtain the carrier chrominance signal, and an adding circuit for adding the input composite color video signal and the output signal of the 1 H delay circuit to obtain the luminance signal.This conventional separating circuit having the comb filter construction operated normally when the input signal was made up from the luminance signal and the carrier chrominance signal which are maintained in a frequency-interleaving relationship, such as the standard system composite color television signal. However, in the color display signal which is generated from the color display signal generating device of a personal computer and the like, the chrominance subcarrier frequency is not strictly made equal to 1/2 an odd number multiple of the horizontal scanning frequency H' that is, the above frequency-interleaving relationship does not exist between the luminance signal and the carrier chrominance signal.Hence, in the separating circuit having the comb filter construction, it was impossible to completely separate the above type of a color display signal to the luminance signal and the carrier chrominance signal, and there were disadvantages in that the picture quality became poor due to the dot interference and the cross color interference.
Accordingly, it is a general object of the present invention to provide a novel and useful color display system in which the above described disadvantages have been eliminated.
The present invention provides a color display system comprising, a signal generating device comprising a carrier chrominance signal generator for generating a carrier chrominance signal, a luminance signal generator for generating a luminance signal, a first output terminal for directly producing an output carrier chrominance signal of said carrier chrominance signal generator, and a second output terminal for directly producing an output luminance signal of said luminance signal generator, and a color display monitoring receiver comprising a first input terminal coupled with the first output terminal of said signal generating device and supplied with said output carrier chrominance signal, a second input terminal coupled with the second output terminal and supplied with said output luminance signal, a carrier chrominance signal demodulating circuit supplied with the carrier chrominance signal from said first input terminal, a luminance signal processing circuit supplied with the luminance signal from said second input terminal, and color display means supplied with output signals of said carrier chrominance signal demodulating circuit and said luminance signal processing circuit, for carrying out a color display.
Another and more specific object of the present invention is to provide a color display system which independently produces the carrier chrominance signal and the luminance signal which are generated from a color display signal generating device, and independently supplies these signals to a color display monitoring receiver to be supplied to predetermined circuits within the receiver. According to the system of the present invention, the carrier chrominance signal and the luminance signal are transmitted independently and the color display signal is not transmitted in the form of a composite color video signal in which the luminance signal and the carrier chrominance signal are multiplexed. Thus, it is unnecessary to separate the composite color video signal into the carrier chrominance signal and the luminance signal in the color display monitoring receiver.Hence, it is possible to obtain a clear color display picture without accompanying deterioration in the picture quality due to causes such as the dot interference, cross color interference, overshoot, and ringing.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.
Fig. 1 is a systematic block diagram showing a conventional color display system; and
Fig. 2 is a systematic block diagram showing an embodiment of a color display system according to the present invention.
As shown in Fig. 1, a conventional color display system was made up from a color display signal generating device 10 and a color display monitoring . eceiver 11. In the color display signal generating device 10, a carrier chrominance signal which is generated from a carrier chrominance signal generator 1 2 and a luminance signal which is generated from a luminance signal generator 13, are respectively supplied to an adding circuit 14. The carrier chrominance signal and the luminance signal are multiplexed in the adding circuit 14, and is produced through an output terminal 1 5 as a composite color display signal which is in ccnformance wioh a standard system composite color video signal.
The composite color display signal from the output terminal 15, is transmitted to an input terminal 17 of the color display monitoring receiver 11, through a connector cable 1 6. The composite color display signal which is transmitted to the input terminal 17, is supplied to a separating circuit 18. As described before, the separating circuit 18 comprises a bandpass filter and a band suppression filter, or comprises a 1 H delay circuit, a subtracting circuit, and an adding circuit, and separates the input composite color display signal into the carrier chrominance signal and the luminance signal.The separated carrier chrominance signal is supplied to a carrier chrominance signal demodulating circuit 1 9 wherein the carrier chrominance signal is demodulated, and color difference signals which are obtained from the carrier chrominance signal demodulating circuit 1 9 are supplied to a matrix circuit 21. On the other hand, the luminance signal which is separated in the separating circuit 18, is supplied to a luminance signal processing circuit 20 wherein the luminance signal is subjected to a predetermined signal processing such as amplification. The processed luminance signal which is obtained from the luminance signal processing circuit 20, is also supplied to the matrix circuit 21.Three primary color signals which are obtained from the matrix circuit 21, are supplied to a cathode ray tube (CRT) 22, and the color display is carried out on the screen on the CRT 22.
However, this conventional color display system is designed to produce a composite color display signal which is in conformance with the standard system, from the output terminal 1 5 of the color display signal generating device 10, because a standard system broadcasting color television receiver is used as the color display monitoring receiver in most cases. Hence, the color television receiver was originally provided with the separating circuit 18, but the receiver exclusively for the color display was also provided with a separating circuit to separate the composite color display signal into the carrier chrominance signal and the luminance signal.
Accordingly, a separating circuit was provided in both the television receiver and the color display monitoring receiver, and regardless of which type of separating circuit was employed, it accompanied the disadvantages described before.
The present invention has eliminated the above disadvantages, and an embodiment of the present invention is shown in Fig. 2. In Fig. 2, those parts which sre the same as those corresponding parts in Fig. 1 are designated by the same reference numerals, and their description will be omitted.
In a color display signal generating device 30,, the output carrier chrominance signal of the ,carrier chrominance signal generator 12 is supplied to the adding circuit 14, and is also supplied directly to an output terminal 32. The output luminance signal of the luminance signal generator 13, is supplied to the adding circuit 14, and is also supplied directly to an output terminal 33.
Input terminals 34 and 35 are provided in a color display monitoring receiver 31. The input terminal 34 is coupled to the output terminal 32 by a cable 36, and the input terminal 35 is coupled to the output terminal 33 by a cable 37.
The input terminal 34 is connected to a contact a of a switch 38, and the input terminal 35 is connected to a contact a of a switch 39. Contacts b of the switches 38 and 39, are respectively coupled to the separating circuit 18. The output of the switch 38 is coupled to the input of the carrier chrominance signal demodulating circuit 19, and the output of the switch 39 is coupled to the input of the luminance signal processing circuit 20. In a normal state, the switches 38 and 39 are respectively connected to the contacts a.
Accordingly, the carrier chrominance signal which is generated from the carrier chrominance signal generator 12, passes through the terminal 32, the cable 36, the terminal 34, and the switch 38, and reaches the carrier chrominance signal demodulating circuit 1 9 directly. On the other hand, the luminance signal which is generated from the luminance signal generator 13 passes through the terminal 33, the cable 37, the terminal 35, and the switch 39, and reaches the
luminance signal processing circuit 20 directly,
independently of the carrier chrominance signal.
The output signals of the carrier chrominance signal demodulating circuit 1 9 and the luminance signal processing circuit 20, are respectively supplied to the matrix circuit 21, and the output signals of the matrix circuit 21 are displayed in color on the CRT 22.
According to the system of the present invention, the carrier chrominance signal is directly supplied to the carrier chrominance signal demodulating circuit 19 and the luminance signal is directly supplied to the luminance signal processing circuit 20, without being passed through the adding circuit 14 and the separating circuit 18. Thus, the various problems described before which are introduced when the carrier chrominance signal and the luminance signal are separated in the separating circuit 18, will not be introduced according to the present invention.
Therefore, it is possible to obtain a color display on the CRT 22, which accompanies no cross color interference and dot interference. Further, because the luminance signal does not pass through a band suppression filter, the luminance signal processing circuit 20 may be designed to sufficiently process up to the high frequency range, and the resolution can be improved. In addition, the signal band in which the carrier chrominance signal demodulating circuit 1 9 can carry out the demodulation, may be set to a large band, and the color resolution can be improved.
Accordingly, it is possible to obtain a clear color display picture in which the luminance and chrominance resolutions are high.
By the provision of the switches 38 and 39, the output signals of the separating circuit 1 8 will not be supplied to the carrier chrominance signal demodulating circuit 19 and the luminance signal processing circuit 20, and-problems will thus not occur, even if the input terminal 1 7 is erroneously coupled to a different color display signal generating device.
When the color display signal generating device 30 is to be used with the conventional color display monitoring receiver 11 , the output terminal 1 5 which is coupled to the adding circuit 14 is used. In addition, when the color display monitoring receiver 31 is to be used with the conventional color display signal generating device 10, the input terminal 1 7 is used, and the switches 38 and 39 are respectively connected to the contacts b. Hence, the composite color display signal which is generated from the conventional color display signal generating device 10 and obtained through the input
terminal 17, is separated into the carrier chrominance signal and the luminance signal in the separating circuit 18, and the separated carrier chrominance signal is supplied to the carrier chrominance signal demodulating circuit 19 while the separated luminance signal is supplied to the luminance signal processing circuit 20.
Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.
Claims (3)
1. A color display system comprising:
a signal generating device comprising a carrier
chrominance signal generator for generating
a carrier chrominance signal, a luminance
signal generator for generating a luminance
signal, a first output terminal for directly
producing an output carrier chrominance
signal of said carrier chrominance signal
generator, and a second output terminal for
directly producing an output luminance
signal of said luminance signal generator;;
and
a color display monitoring receiver comprising
a first input terminal coupled with the first
output terminal of said signal generating
device and supplied with said output carrier
chrominance signal, a second input terminal
coupled with the second output terminal and
supplied with said output luminance signal, a
carrier chorminance signal demodulating
circuit supplied with the carrier chrominance
signal from said first input terminal, a
luminance signal processing circuit supplied
with the luminance signal from said second
input terminal, and color display means
supplied with output signals of said carrier
chrominance signal demodulating circuit and
said luminance signal processing circuit, for
carrying out a color display.
2. A color display system as claimed in claim 1 in which said signal generating device further comprises an adding circuit supplied with the output carrier chrominance signal of said carrier chrominance signal generator and the output luminance signal of said luminance signal generator, for multiplexing the carrier chrominance signal and the luminance signal and for producing a composite color display signal, and a third output terminal for producing an output composite color display signal of said adding circuit, and said color display monitoring receiver further comprises a third input terminal coupled to said third output terminal and supplied with said composite color display signal, and a separating circuit supplied with the composite color display signal from said third input terminal, for separating the composite color display signal into the carrier chrominance signal and the luminance signal.
3. A color display system as claimed in claim 2 in which said color display monitoring receiver further comprises a first switch for selectively supplying the signal from said first input terminal and a signal from said separating circuit to said carrier chrominance signal demodulating circuit, and a second switch for selectively supplying the signal from said second input terminal and a signal from said separating circuit to said luminance signal processing circuit.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57229587A JPS59123881A (en) | 1982-12-29 | 1982-12-29 | Color display system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8334521D0 GB8334521D0 (en) | 1984-02-01 |
| GB2134743A true GB2134743A (en) | 1984-08-15 |
Family
ID=16894513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08334521A Withdrawn GB2134743A (en) | 1982-12-29 | 1983-12-29 | Color display system |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS59123881A (en) |
| DE (1) | DE3347371C2 (en) |
| GB (1) | GB2134743A (en) |
| MY (1) | MY104835A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4802000A (en) * | 1987-12-22 | 1989-01-31 | Rca Licensing Corporation | Video switching apparatus having interference prevention feature |
| US4963979A (en) * | 1989-04-20 | 1990-10-16 | Rca Licensing Corporation | Television receiver with auxiliary input connector for video signals of a separated Y-C format |
| US5032900A (en) * | 1990-04-30 | 1991-07-16 | Thomson Consumer Electronics, Inc. | Television receiver with auxiliary input connector for video signals of a separated y-c format |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2679050B2 (en) * | 1987-07-10 | 1997-11-19 | ソニー株式会社 | Video signal processing device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB773204A (en) * | 1953-06-29 | 1957-04-24 | Rca Corp | Colour television recording and reproducing |
| GB798948A (en) * | 1954-05-03 | 1958-07-30 | Rca Corp | System for reproducing signals from a magnetic medium |
| GB1225683A (en) * | 1967-03-11 | 1971-03-17 | ||
| EP0041872A1 (en) * | 1980-06-11 | 1981-12-16 | Matsushita Electric Industrial Co., Ltd. | Phase difference compensation between separately recorded luminance and chrominance signals |
-
1982
- 1982-12-29 JP JP57229587A patent/JPS59123881A/en active Pending
-
1983
- 1983-12-29 DE DE3347371A patent/DE3347371C2/en not_active Expired
- 1983-12-29 GB GB08334521A patent/GB2134743A/en not_active Withdrawn
-
1988
- 1988-12-30 MY MYPI88001572A patent/MY104835A/en unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB773204A (en) * | 1953-06-29 | 1957-04-24 | Rca Corp | Colour television recording and reproducing |
| GB798948A (en) * | 1954-05-03 | 1958-07-30 | Rca Corp | System for reproducing signals from a magnetic medium |
| GB1225683A (en) * | 1967-03-11 | 1971-03-17 | ||
| EP0041872A1 (en) * | 1980-06-11 | 1981-12-16 | Matsushita Electric Industrial Co., Ltd. | Phase difference compensation between separately recorded luminance and chrominance signals |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4802000A (en) * | 1987-12-22 | 1989-01-31 | Rca Licensing Corporation | Video switching apparatus having interference prevention feature |
| US4963979A (en) * | 1989-04-20 | 1990-10-16 | Rca Licensing Corporation | Television receiver with auxiliary input connector for video signals of a separated Y-C format |
| US5032900A (en) * | 1990-04-30 | 1991-07-16 | Thomson Consumer Electronics, Inc. | Television receiver with auxiliary input connector for video signals of a separated y-c format |
| EP0455131A2 (en) * | 1990-04-30 | 1991-11-06 | Thomson Consumer Electronics, Inc. | Television receiver with auxiliary input connector for video signals of a separated Y-C-format |
| EP0455131A3 (en) * | 1990-04-30 | 1992-03-11 | Thomson Consumer Electronics, Inc. | Television receiver with auxiliary input connector for video signals of a separated y-c-format |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8334521D0 (en) | 1984-02-01 |
| MY104835A (en) | 1994-06-30 |
| JPS59123881A (en) | 1984-07-17 |
| DE3347371A1 (en) | 1984-07-12 |
| DE3347371C2 (en) | 1985-07-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4072984A (en) | Chrominance-luminance separator | |
| US4944032A (en) | Multiplex signal processing apparatus | |
| CA2065461C (en) | System and method for combining multiple composite video signals | |
| KR100188832B1 (en) | Transmitting auxiliary information in a television signal | |
| US5023721A (en) | TV of internal PiP type for receiving the character multibroadcasting | |
| EP0120390A2 (en) | Television signal transmission system | |
| EP0138482B1 (en) | Video signal superimposing device | |
| US5136380A (en) | Display signal device and method for providing compatibility between ntsc television and hdtv | |
| US4879606A (en) | EDTV recording apparatus | |
| JPH0832074B2 (en) | Television equipment | |
| US4809060A (en) | Hanging dot reduction arrangement | |
| JPH06327030A (en) | Motion detecting circuit | |
| MY105963A (en) | Television apparatus with picture in picture processing | |
| US5107340A (en) | Digital video signal noise-reduction apparatus with high pass and low pass filter | |
| GB2134743A (en) | Color display system | |
| US5389975A (en) | Video additive information identifying device with plural inputs | |
| EP0464879B1 (en) | Apparatus for separating luminance and chrominance signals and the method thereof | |
| US5140410A (en) | Chrominance signal mixing circuit in a motion adaptive type signal separator | |
| Grafe et al. | Interfield noise and cross color reduction IC for flicker-free TV receivers | |
| EP0329382B1 (en) | Luminance signal/color signal separation circuit | |
| KR940002164B1 (en) | Hanging dot deduction system | |
| CA2203735A1 (en) | Up-converter and scanning line conversion method | |
| KR910013891A (en) | Auxiliary video information encoding and decoding device for television system | |
| KR940001861Y1 (en) | Apparatus for selecting pal/secam luminance signals respectively | |
| EP0334351A3 (en) | Video signal processing circuit and an insertion circuit utilized therein |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |