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PAL-S
PAL-S is the system of television receiver sets in the early days of the PAL system. Here PAL stands for ''Phase alternating at line rate'' and S stands for ''simple''. PAL system The color hue modulates the phase of a subcarrier named color carrier. In PAL system the polarity of the phase in each frame is reversed to neutralize the undesirable phase shifts introduced during transmission. Thus the effect of undesirable phase shift is positive in one frame and negative in the second frame. Averaging the two, the effect of the undesirable phase shifts in two consecutive frames cancel each other. The PAL-S receiver In the early days of the PAL system, it was proposed that, the human eye can average the slightly different color hues in two consecutive frames and perceive the original color. The television receiver sets which rely on optical averaging were called PAL-S receivers. The problems in PAL-S However, it soon turned out that the optical averaging had problems. Whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrominance Subcarrier
The chrominance subcarrier is a separate subcarrier signal that carries the color information during transmission of a composite video signal. It is modulated and synchronized using the colorburst signal and then attached to the back porch of the signal. By synchronizing the subcarrier with the local oscillator of the television receiver A television set or television receiver (more commonly called TV, TV set, television, telly, or tele) is an electronic device for viewing and hearing television broadcasts, or as a computer monitor. It combines a tuner, display, and loudspeake ..., the RGB colors can be decoded successfully. Video signal {{tv-tech-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Gain
Differential gain is a kind of linearity distortion that affects the amplification and transmission of analog signals. It can visibly affect color saturation in analog TV broadcasting. Composite color video signal The composite color video signal (CCVS) consists of three terms: *Luminance (monochrome) signal *Auxiliary signals (sync pulse and blanking level signals ) *Chrominance, which is actually a subcarrier modulated by chroma information The first two terms are usually called composite video signal (CVS) The modulation technique of the color subcarrier is quadrature amplitude modulation (QUAM) both in PAL and NTSC systems. The amplitude of the color signal represents the saturation (purity) in both systems. On the other hand, the level of the CVS represents the brightness. So in order to reproduce the original vision in the receiver the ratio between these two pieces of information should be kept constant in the receiver. Nonlinearity in the broadcast system The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Phase
Differential phase is a kind of linearity distortion which affects the color hue in TV broadcasting. Composite color video signal Composite color video signal (CCVS) consists of three terms: *Monochrome ( luminance) signal *Auxiliary signals ( sync pulse and blanking signals) *Color signal, which is actually a subcarrier modulated by chroma information The first two terms are usually called composite video signal (CVS) The modulation technique of the color subcarrier is quadrature amplitude modulation Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signa ... (QAM) both in PAL and NTSC systems. The amplitude of the color signal represents the saturation of the color and the phase lag of the color signal with respect to a certain reference which is called colorburst represents t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Technology
The technology of television has evolved since its early days using a mechanical system invented by Paul Gottlieb Nipkow in 1884. Every television system works on the scanning principle first implemented in the rotating disk scanner of Nipkow. This turns a two-dimensional image into a time series of signals that represent the brightness and color of each resolvable element of the picture. By repeating a two-dimensional image quickly enough, the impression of motion can be transmitted as well. For the receiving apparatus to reconstruct the image, synchronization information is included in the signal to allow proper placement of each line within the image and to identify when a complete image has been transmitted and a new image is to follow. While mechanically scanned systems were experimentally used, television as a mass medium was made practical by the development of electronic camera tubes and displays. By the turn of the 21st century, it was technically feasible to replace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
