Facsimile and static presentation processing – Static presentation processing – Attribute control
Patent
1983-03-10
1989-07-11
Shepperd, John W.
Facsimile and static presentation processing
Static presentation processing
Attribute control
358141, 358180, H04N 1100
Patent
active
048476765
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to color television systems.
All existing broadcast television standards have a picture aspect ratio (the ratio of picture width to picture height) of 4:3. This ratio was chosen for compatibility with ordinary motion picture standards.
A greater sense of realism could be conveyed by television pictures if the aspect ratio were increased so that the picture filled more of the viewer's field of view. Wide-screen presentations are now commonplace in cinemas. A number of proposals have been made for television standards with a higher aspect ratio, but these all involve a higher video bandwidth.
This invention enables the provision of a higher aspect ratio within the same bandwidth as existing television standards.
In the U.K. System I 625-line standard, the total length of the line is 64 .mu.s. However, only 52 .mu.s is used for the picture. This is known as the active line period. The remaining 12 .mu.s, known as the horizontal blanking interval, is required to transmit a synchronising pulse for the horizontal synchronising of the receiver, a black level pulse which provides a d.c. clamping reference, and a burst of color subcarrier to synchronise the receiver's PAL decoding circuits. The receiver uses the time of the horizontal blanking interval for horizontal flyback of the scanning spot in the cathode ray tube to the start of the next line.
SUMMARY OF THE INVENTION
The present invention is defined in the appended claims to which reference should now be made.
In a system embodying this invention we propose that the total line length of 64 .mu.s is retained, but the active line length is increased. The remaining time would be used to provide horizontal synchronising information and a period of black level as a d.c. clamping reference.
In this way it is possible to achieve an aspect ratio of greater than 4:3. The active line may constitute at least 85% or even 90% of the line period, and the color synchronising information may be transmitted either during the black level pulse or during the vertical blanking interval, so that there is no separate period of color synchronising information during the line period. As a further alternative, color synchronising information could be obtained from the digital sound signal or its carrier or multiplex system.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detail, by way of example, with reference to the drawings, in which:
FIG. 1 illustrates in diagrammatic form one television line according to existing television standards;
FIG. 2 is a similar drawing of a first television line embodying this invention, using a narrow synchronising (sync.) pulse and a reduced color burst superposed on the black level portion of the signal;
FIG. 3 is a similar drawing of a second television line embodying this invention using a wider sync. pulse but with the color synchronising information transmitted separately.
FIG. 4 is a schematic diagram showing how color synchronizing information may be transmitted with the sound signal;
FIG. 5 shows a 5 MHz bandwidth signal; and
FIG. 6 shows, schematically, transmission of a color burst in a line in the vertical blanking interval.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The conventional television line shown in FIG. 1 has a line period of 64 .mu.s, of which 52 .mu.s constitutes the active video signal, this being about 81% of the line period. The remaining 12 .mu.s is used as flyback time and for synchronising information. More particularly, the line commences with a line sync. pulse and is then followed by a period of black level transmitted as a d.c. reference and on part of which is superposed the color synchronising burst. All this is well known.
In accordance with the embodiments shown in FIGS. 2 and 3, the active video signal occupies 60 .mu.s or nearly 94% of the line period. This gives an aspect ratio increased from 4:3 or 1.333 to 1.538. Coloring information may be transmitted in the active video using the PAL system substantially as at pr
REFERENCES:
patent: 2820091 (1958-01-01), Parker et al.
patent: 3097262 (1963-07-01), Ehenhaft
patent: 3507981 (1970-04-01), Eilenberger
patent: 3781463 (1973-12-01), VandenBussche
patent: 4335393 (1982-06-01), Pearson
patent: 4400717 (1983-08-01), Southworth et al.
C. W. Rhodes, Time Division Multiplex of Time Compressed Chrominance for a Compatible High Definition Television System, IEEE Transactions on Consumer Electronics, vol. CE28, No. 4, Nov. 1982, pp. 592-602.
Zworykin et al., Television The Electronics of Image Transmission in Color and Monochrome, p. 544, 1954, John Wiley & Sons Inc.
Television Standards and Practice, Edited by D. G. Fink, McGraw-Hill Book Co., Inc., 1943, p. 36.
NHK Laboratories Note, No. 192, Dec. 1975, "The Present State of High Definition Television", pp. 1 & 3-8.
Oliphant Andrew
Sandbank Charles P.
British Broadcasting Corporation
O'Connell Robert F.
Shepperd John W.
LandOfFree
Color television system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Color television system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color television system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-440557