Measurement Basics
R&S
®
FSW-K40
29
User Manual 1173.9286.02 ─ 15
Frequency tracking
When you are using the frequency tracking, the application tracks drifting frequencies
of unstable DUTs. It internally adjusts and keeps a lock on the nominal frequency of
the DUT.
Figure 4-6: Frequency and level tracking
Tracking bandwidth
The tracking bandwidth defines the bandwidth within which the application tracks the
frequency.
Normally, the application adjusts the sample rate to the half decade it is currently mea-
suring. For half decades that are near the carrier, the sample rate is small. Half deca-
des far from the carrier use a higher sample rate. However, in case of drifting signals,
this method may result in data loss because the default bandwidth for a half decade
might be too small for the actual drift in the frequency. In that case, you can define the
tracking bandwidth which increases the sample rate if necessary and thus increases
the chance to capture the signal.
Figure 4-7: Frequency tracking with tracking bandwidth turned off (left) and a tracking bandwidth of
100
Hz (right)
Frequency Determination
