A-B             C-D             E-L            M-P            R-Z


RC (Radial Contrast)
The radial contrast is the difference in reflectivity of spirals and the areas parts between spirals. According to the Orange Book, RC must be over 20% on a recorded disc and over 5% on a blank disc. The RC is measured at 10 points across the disc's surface. It is calculated as follows :

Red Book
The CD - DA standards.

REF (Reflectivity)
Reflectivity is adjusted according to a reference disc and is used to detect and normalize variations in reflection.

RIFF (Resource Interchange File Format)
File format for storing diagrams, sounds, and animations.

RN (Radial Noise)
Radial noise may be present when tracks are damaged. It is found in a frequency range of between 500 and 2500 Hz.


SVY (Scanning Velocity)
This is between 1.2 m/sec and 1.4 m/sec. If it falls below 1.2 m/sec I3 length information is affected. The SVY parameter represents the speed at which the reading light passes. If the speed is too high, the I3 level will be too weak. SVY is measured as vertical information at 10 points across the data area on the disc. The result is returned as a minimum, maximum and average. SVY variations on the disc must be be lower than ± 0.01 m/sec (CD-CATS).

SLD (Start Lead In)
The beginning of the lead-in area must be to the radius 23,1 mms. The reader uses this surface to identify the table of contents (TOC). If the SLD is outside specification the reader will not be able to identify where the TOC is.

SPD (Start of Program Diameter)
This must be located between the radius 24.8 mms and 25.04 mms. The SPD parameter is used by the reader to find the beginning of a track. If the SPD parameter is outside specification, the reader will take more time to find the first track.

A metal tool which creates the spiral (groove) and is held in the injection mold.

The main polycarbonate body of a CD to which are applied several other layers.


TIFF (Tagged Image File Format)
When a picture is scanned, one possible format is can be saved as is a TIFF.

TOC (Table Of Contents)
Information located in the lead-in area. It specifies the location of the beginning of every track and the type of disc.

In audio, each song is represented by a track. Computerized data sees this only as one track. If the CD-ROM is mixed format, it holds both a data and sound track. A CD can hold up to 99 tracks.

Track Pitch
Physical distance between two curves of a spiral, equivalent to between 1,5 to 1,7µ.

Turnaround Time
Time needed to manufacture a CD, DVD, or Blu-ray.


Volume description
The area at the beginning of the disc reserved for recording such information as the origin, the copyright, etc.


W-O (Write Once)
Optical disc writable once only.

WORM (Write Once, Read Many)
Identical to W-O


XT (Cross Talk)
Measure of the quantity of noise present in high-frequency signals. The XT must be lower than 50%. Excessive XT disturbs HF signals, which in turn increases BLER.


Yellow Book
When Philips and Sony created the CD standard, it was published in a book with a yellow cover. Hence the name.

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