Tektronix WFM 601i, User Manual

Page: 126 / 135

Glossary
Glossary–2
WFM 601i Serial Component Monitor
Diamond A simplified vector display for RGB signals that defines the valid
gamut limits in the form of two diamonds.
Distortion If a sine wave of a single frequency is put into a system, and
harmonic content at multiples of that frequency appears at the output, there is
harmonic distortion present in the system. Harmonic distortion is caused by
nonlinearities in the system.
Frame
A frame (sometimes called a “picture”) contains all the information
required for a complete picture. For interlaced scan systems, there are two fields
in a frame.
Gamma (NTSC)
Since picture monitors have a nonlinear relationship between
the input voltage and brightness, the signal must be correspondingly predis-
torted. Gamma correction is always done at the source (camera) in television
systems: the R, G, and B signals are converted to R
1
/
V
, G
1
/
V
, and B
1
/
V
. Values of
about 2.2 are typically used for gamma.
Gamma (PAL)
Since picture monitors have a nonlinear relationship between
the input voltage and brightness, the signal must be correspondingly predis-
torted. Gamma correction is always done at the source (camera) in television
systems: the R, G, and B signals are converted to R
1
/
V
, G
1
/
V
, and B
1
/
V
. Values for
gamma range from 2.2 to 2.8.
Gamut
See Color Gamut.
GBR
The same signals as RGB, but rearranged in sequence to correspond with
SMPTE specification.
Graticule
The scale which is used to quantify the information on a waveform
monitor or vectorscope display. Graticules may either be screened onto the
faceplate of the CRT itself (internal graticule), or onto a piece of glass or plastic
which fits in front of the CRT (external graticule). They can also be electronical-
ly generated.
Lightning Lightning display. A display, for use with SMPTE specified color
difference signals (Y, P
B
, P
R
), that plots the two color difference signals against
luminance to create a display similar in appearance to a lightning bolt.
Linear Distortion
Refers to distortions which are independent of signal
amplitude.