BK Precision 1249B, Instruction Manual

Page: 8 / 41

8
DEFINITIONS OF TERMS
BARS Pattern. See “NTSC Color Bars”.
Back Porch.
The portion of a composite video signal between
the trailing edge of the horizontal sync pulse and the end of the
horizontal blanking pedestal. The color burst occurs during the
back porch interval.
Blanking Level.
The level of the front and back porches. Zero
IEEE units.
Burst.
See "Color Burst".
CATV
Cable Television. Also used for Community Antenna
Television.
CCTV.
Closed-circuit television.
Chroma or Chrominance
. The color information contained in
a video signal, consisting of hue (phase angle) and saturation
(amplitude) of the color subcamer.
Chroma Amplitude.
. Amplitude of 3.58MHz color subcarrier.
Represents saturation.
Chroma Phase Angle.
Phase angle of 3.58MHz color
subcarrier. Represents hue.
Color Bars.
See "NTSC Color Bars".
Color Burst. A few (8 to 10) cycles of 3.58MHz color subcarrier
which occur during the back porch interval. Color burst amplitude is
40 IEEE units and phase is 180°. The color oscillator of a color
television receiver is phase locked to the color burst.
Color Subcarrier.
The 3.58MHz signal which carves color
information. This signal is superimposed on the luminance level.
Amplitude of the color subcarrier represents saturation and phase
angle represents hue.
Composite Video Signal.
The entire video signal consisting of
blanking pulses, sync pulses, color burst, and chrominance and
luminance information.
Duty Cycle.
Percentage of cycle during which pulse is working.
A square wave has a 50% duty cycle. Horizontal sync pulses have
about 8% duty cycle-about 5µs pulse width at 63.5µs pulse
repetition period.
EIA.
Electronic Industries Association.
Equalizing Pulse.
A portion of the vertical blanking interval
which is made up of blanking level and six pulses (8% duty cycle
at -40 IEEE units) at one-half the width of horizontal sync pulses
and at twice the repetition rate. One equalizing pulse occurs
immediately before, and another immediately after, the vertical
sync pulse.