VECTOR NETWORK ANALYSIS Measurement technique which allows complete characterization of single or multiport networks. The magnitude and phase of the measurand are determined. The transmission function and the reflection coefficient are usually measured in RF engineering.
VIDEO BANDWIDTH (VBW) The bandwidth of a low-pass filter connected downstream of the detector circuits. This causes the amplitude or power level to be weighted with a time constant to smooth out the noise components in the measured signal (averaging). The selected video filter affects the sweep time. Due to their longer settling times, narrow filters require longer sweep times than wide filters. However, wide filters do not average (reduce) the noise as much. When selecting a video filter you should take into account that rapidly changing signals (e.g. TV signals) might not be detected correctly. In such cases a sufficiently large video bandwidth should be selected. When measuring unknown signals the video bandwidth should be changed in steps and the effects on the measurement results monitored.
