Bird-technologies 5019D-Manual Manuel d'utilisateur télécharger pdf (Page 21)

Video Filter

Figure 2 Video Filter Settings, 300 kHz Signal

Except for average power and VSWR measurements, all WPS

measurements rely on a variable video filter to improve accu-

racy. This filter 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 band-

width). 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 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

Bandwidth

CW Burst (b.w. > 200 ns), CDMA, WCDMA,

DQPSK, DAB/DVB-T

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Bird-technologies 5019D-Manual Manuel d'utilisateur Page 21