Video filter – Bird Technologies SA-6000EX User Manual
Page 126
Bird Technologies
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Video Filter
Except for average power and VSWR measurements, all WPS mea-
surements rely on a variable video filter to improve accuracy. This fil-
ter can be set to either 4.5 kHz, 400 kHz, or full bandwidth. It should
be as narrow as possible while still being larger than the demodulated
signal bandwidth (video bandwidth). Narrowing the filter limits the
noise contribution caused by interfering signals. Listed below are
some common modulation schemes and the appropriate video filter.
Video Filter
Settings, 300
kHz Signal
Video Filter
Modulation Type
4.5 kHz
CW Burst (Burst width > 150 µs), Voice Band AM,
FM, Phase Modulation, Tetra
400 kHz
CW Burst (b.w. > 3 µs), GSM, 50 kHz AM, DQPSK
Full Band-
width
CW Burst (b.w. > 200 ns), CDMA, WCDMA,
DQPSK, DAB/DVB-T
Filter
Too Small
Filter
Too Wide
Correct
Filter
Noise
Signal
Toggle
between
4.5 KHz,
400 KHz,
Full Band