Glossary
1760 SeriesComponent Waveform/Vector Monitor User Manu al G-5
Frequency Modulation (FM) is the process by which
the frequency of a carrier signal is varied in proport ion to the
signal of interest. In both the NTSC and PALt elevision sys-
tems, audio informationis transmitted using FM.
Frame A frame (sometimes called a “picture”) contains all
the information required for a complete picture. For inter-
laced scan systems,there are two fields in a frame.
Front Porch The portion of the video signal between the
end of active picturetime and the leading edge of horizontal
sync.
Gamma (NTSC) Sincepicture monitors have a nonlinear
relationship between the input voltage a nd brightness, the
signal must be correspondingly predistorted. Gamma correc-
tion is always done at the source (camera) in te levision sys-
tems: the R, G, and B signals are converted to R1/V
,G
1/V
,
and B1/V
. Values of about 2.2 are typica lly used for gamma.
Gamma (PAL) Since picture monitors have a nonlinear
relationship between the input voltage a nd brightness, the
signal must be correspondingly predistorted. Gamma correc-
tion is always done at the source (camera) in te levision sys-
tems: the R, G, and B signals are converted to R1/V
,G
1/V
,
and B1/V
. Values for gamma range from 2.2 t o 2.8.
Gen Lock The process of locking both sync and burst of
one signal to sync and burst of another, making the two sig-
nals completely synchronous.
Graticule The scale which is usedto quantify the informa-
tion on a waveformmonitor or vectorscope display. Grati-
cules may eitherbe screened onto the faceplate of the CRT
itself (internalgraticule), or onto a piece of glass or plastic
which fits in front of the CRT (external graticule). They can
also be electronically generate d.
HorizontalBlanking Horizontal blanking is the e ntire
time between the endof the active picture time of one line
and the beginningof active picture time of the next line. It
extends from the start of front porch to the end of back
porch.