Tektronix WFM601, Service Manual

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Glossary
WFM601 Serial Component Monitor
Glossary–5
Lightning Lightning display. A display, for use with SMPTE specified color
difference signal (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.
Luminance The signal which represents brightness, or the amount of light in
the picture. This is the only signal required for black and white pictures, and for
color systems it is obtained as a weighted sum (Y = 0.3R + 0.59G + 0.11B) of
the R, G, and B signals.
Modulated (NTSC)
When referring to television test signals, this term implies
that chrominance information is present. (For example, a modulated staircase
has subcarrier on each step.)
Modulated (PAL) When referring to television test signals, this term implies
that chrominance information is present. (For example, a modulated ramp has
subcarrier on each step.)
Modulation A process which allows signal information to be moved to other
frequencies in order to facilitate transmission or frequency–domain multiplexing.
See AM and FM for details.
Non–Linear Distortion
Refers to distortions which are amplitude–dependent.
NTSC
National Television System Committee. The organization which
developed the television standard currently in use in the United States, Canada,
and Japan. Now generally used to refer to that standard.
PAL
Phase Alternate Line. Refers to one of the television systems used in
Europe and many other parts of the world. The phase of one of the color
difference signals alternates from line to line to help cancel out phase errors.
Quadrature AM A process which allows two different signals to modulate a
single carrier frequency. The two signals of interest Amplitude Modulate carrier
signals which are the same frequency but differ in phase by 90 degrees (hence
the Quadrature notation). The two resultant signals can be added together, and
both signals recovered at the other end, if they are also demodulated 90 degrees
apart.
Quadrature Distortion
Distortion resulting from the asymmetry of sidebands
used in vestigial sideband television transmission. Quadrature distortion appears
when envelope detection is used, but can be eliminated by using a synchronous
demodulator.
RF
Radio Frequency. In television applications, RF generally refers to the
television signal after the picture carrier modulation process