ADInstruments S7200 Operation Manual page 271

AD INSTRUMENTS S7200 TV Signal Analyzer Operation Manual
in even field. These lines are used to transmit blanking signal for the electron
beam at the end of the line scanning and field scanning can come back to the start
point of the picture.
In 625 scanning lines system, every field has 25 lines as the flyback line, so every
frame only has 575 effective lines.
When engineers test TV system, they often use full field test signal, this operation
require engineers to stop TV program broadcast. Obviously, if we want to test the
dynamic parameters, we cannot do measurement and broadcast TV program at
the same time. With the development of the TV industry, TV program broadcast
hours continuously increase. TV program service providers hope to monitor TV
system performance parameters and judge whether the broadcast equipment
work well or not according to these parameters. They can modify these
equipments according to these parameters. The requirement is very important for
TV program service providers.
Vertical blanking interval is not used to transmit any information, later the
researchers use these free lines to convey auxiliary signals for increasing the
bandwidth utilization ratio. Vertical Interval Test Signal (VITS) can give important
system dynamic performance parameters without influencing the TV program
broadcast. VITS also provides the possibility to automatically monitor, modify and
broadcast. Inserting test signals in the vertical blanking interval is used in real time
monitoring, helping to modify and improve TV program transmission quality by at
least determining which parameter is below acceptable quality or below
mandatory thresholds prescribed by the FCC. Now, the VITS signal is an
indispensable part of international and domestic TV signals.
Some signals can measure video parameters: in-channel frequency response,
luminance nonlinear distortion, Differential Gain, Differential Phase, Chrominance
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