Cable equalization, Capacitance, Chroma | Extron electronic RGB 320

Reference and Glossary • Appendix B

Cable equalization –

The method of altering the frequency response of a video amplifier to compensate for high frequency losses in cables that it feeds. See peaking.

Capacitance –

The storing of an electrical charge. Capacitance is a condition that exists between conductors in a cable. At high frequencies, this represents an impedance called capacitive reactance (Xc), which can cause signal loss or distortion.

Chroma –

The characteristics of color information, independent of luminance intensity. Hue and saturation are qualities of chroma. Black, gray and white objects do not have chroma characteristics.

Chrominance signal –

Part of a television signal containing the color information. Abbreviated as C.

Coaxial cable –

A two-conductor wire in which one conductor completely wraps the other conductor, with the two separated by insulation. Constant impedance transmission cable. Abbreviated as coax.

Component video –

Our color television system starts with three channels of information; red, green,

&blue (RGB). In the process of translating these channels to a single composite video signal, they are often first converted to Y, R-Y, and B-Y. Both 3-channel systems, RGB and Y, R -Y, B -Y, are component video signals. They are the components that eventually make up the composite video signal. Higher quality program production is possible if the elements are assembled in the component domain.

Composite sync –

A signal combining horizontal and vertical sync pulses and equalizing pulses, with no picture information and no signal reference level. Sometimes called C, S (as in RGBS) or HV.

Composite video –

An all-in-one video signal comprised of the luminance (black and white), chrominance (color), blanking pulses, sync pulses and color burst.

Contact closure –

A device that provides electrical contact between a designated input pin and ground, causing a device, such as a switcher, to do a particular function.

Contrast –

The range of light and dark values in a picture, or the ratio between the maximum and the minimum brightness values. Low contrast is shown mainly as shades of gray, while high contrast is shown as blacks and whites with very little gray. It is also a TV monitor adjustment that increases or decreases the level of contrast of a displayed picture. Also called white level.

Crosstalk –

Interference between two audio or video signals, usually from an adjacent channel, that adds an undesired signal to the desired signal. Crosstalk is caused by magnetic/capacitative coupling or electrostatic induction, and can occur when there are grounding problems or improper cable shielding. Video symptoms include noise/ghosting, and audio symptoms include signal leakage.

Crosstalk isolation –

Attenuation of an undesired signal introduced by crosstalk.

D connector –

A connector with rounded corners and angled ends, taking on the shape of the letter D. Commonly used in computers and video.

dB –

Decibel. The standard unit used to express gain or loss of power. It indicates the logarithmic ratio of output power divided by input power. A power loss of 3 dB is an attenuation of half of the original value. The term “3 dB down” is used to describe the “half power point”.

DC –

Direct current. The flow of electrons in one direction.

Decibel –

See dB.

Decoder –

A device used to separate the RGBS (red, green, blue and sync) signals from a composite video signal.

Differential audio –

See balanced audio.

B-3	RGB 320 Switching Interface System • User’s Manual • Extron