Introduction To The Different Roles Of Different Interfaces On The TV (III)

Introduction To The Different Roles Of Different Interfaces On The TV (III)

The S-terminal is actually a five-core interface, which consists of two video brightness signals, two video chrominance signals, and one common shielded ground wire.

S-terminal achieves brightness and chrominance separation

It is not difficult to see from its structure that the S-terminal is a device for separating luminance and chrominance output. This design is mainly for the mutual interference of brightness and chrominance when the video program is composite output. However, the S-terminal still needs to mix the two signals of chrominance and luminance into one chrominance signal for imaging, so there is still a case of image quality loss.

S-terminal cable

Careful netizens may find that the odds of S-speakers appearing on flat-panel TVs are getting smaller and smaller, and new products are not equipped with S-terminals, and are now in the process of being phased out.

Color difference component interface: chrominance is subdivided

The color difference component interface uses two identifiers, YPbPr and YCbCr. The former represents the progressive scan color difference output, and the latter represents the interlaced color difference output. Simply put, compared to the AV and S terminals, the color difference is input by dividing the signal into three primary colors of red, green, and blue.

Color difference component interface

The S terminal only separates the chrominance and the luminance, and the color difference component interface not only realizes the separate transmission of chrominance and luminance, but also separates the chromaticity into blue difference and red difference, and the color difference component interface also has a transmission. The line of the Y signal can be used to calculate the green difference signal by the formula, thus avoiding the interference of the S terminal in decoding on the chrominance.

Color difference line

The color difference component interface generally uses three signal lines to respectively transmit bright color and two color difference signals. The three sets of signals are: the brightness is marked with Y, and the blue and red from the three primary color signals, that is, the color difference signal after the luminance signal is removed, labeled as Pb and Pr, or Cb and Cr, respectively, in the joint of the three lines. The distinction is made in green, blue and red respectively. If these three lines are inserted incorrectly with each other, they may not show a picture or show strange colors.

Optical fiber audio interface: prevents digital noise transmission

Optical fiber audio interface TosLink, full name ToshibaLink, which was developed and set by Toshiba Corporation of Japan earlier, has an Optical logo on the back panel of audio-visual equipment. The light audio interface is absolutely optimized for both images and audio.

Optical fiber audio interface

TosLink fiber has been widely used in ordinary low-end CD, LD, MD, DVD players and stereos. Fiber optic connections provide electrical isolation and prevent digital noise from being transmitted through the ground, which helps improve the signal-to-noise ratio of the DAC. However, the time base error is an important factor affecting the sound quality. Therefore, the performance of the digital audio equipment transmission interface should be measured according to the size of the time base error.

The fiber-connected signal undergoes two conversions between the transmitter and the receiver, which produces a timing jitter error (Jitter) that severely affects the sound quality. The materials commonly used in the manufacture of optical fibers are plastic, quartz, glass, etc. Glass fiber (ST) is the most expensive one.

The above interfaces are common types of interfaces on TV sets. Usually different interfaces have different applications and functions. When users select TVs, they can also choose according to their needs. USB capture card HDMI capture card.