4 MEASUREMENT CONDITIONS SETTING
In majority of cases it is sufficient to apply offset to one of the ports, leaving the other
one at the basic frequency (M=1, D=1, Fofs=0).
Below are some examples of offset coefficient calculation at different types of
frequency conversion. Mixer input is connected to port 1, mixer output is connected to
port 2. RF – output frequency, IF – intermediate frequency, LO – local oscillator
frequency. Second port of the Analyzer is running in frequency offset mode:
1. IF = RF – LO Port 2: M = 1, D = 1, Fofs = – LO.
2. IF = LO – RF Port 2: M = – 1, D = 1, Fofs = LO.
3. IF = RF + LO Port 2: M = 1, D = 1, Fofs = LO.
In frequency offset mode, the bottom part of the channel window will indicate each port
frequency span (See figure 4.19).
Figure 4.19 Channel window in frequency offset mode