Rohde & Schwarz FPL1000 Series, User Manual

Page: 379 / 899

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
379 User Manual 1178.3370.02 ─ 03
"0.1 * Span" /
"0.1 * RBW" Sets the step size for the center frequency to 10 % of the span /
RBW.
This is the default setting.
"0.5 * Span" /
"0.5 * RBW" Sets the step size for the center frequency to 50 % of the span /
RBW.
"x * Span" /
"x
* RBW"
Sets the step size for the center frequency to a manually defined fac-
tor of the span / RBW. The "X-Factor" defines the percentage of the
span / RBW.
Values between 1 and 100 % in steps of 1 % are allowed. The default
setting is 10 %.
"= Center" Sets the step size to the value of the center frequency and removes
the coupling of the step size to span or resolution bandwidth. The
used value is indicated in the "Value" field.
"= Marker" This setting is only available if a marker is active.
Sets the step size to the value of the current marker and removes the
coupling of the step size to span or resolution bandwidth. The used
value is indicated in the "Value" field.
"Manual" Defines a fixed step size for the center frequency. Enter the step size
in the "Value" field.
Remote command:
[SENSe:]FREQuency:CENTer:STEP:LINK
on page 643
[SENSe:]FREQuency:CENTer:STEP:LINK:FACTor
on page 644
[SENSe:]FREQuency:CENTer:STEP
on page 643
Frequency Offset
Shifts the displayed frequency range along the x-axis by the defined offset.
This parameter has no effect on the instrument's hardware, or on the captured data or
on data processing. It is simply a manipulation of the final results in which absolute fre-
quency values are displayed. Thus, the x-axis of a spectrum display is shifted by a
constant offset if it shows absolute frequencies, but not if it shows frequencies relative
to the signal's center frequency.
A frequency offset can be used to correct the display of a signal that is slightly distorted
by the measurement setup, for example.
The allowed values range from -100 GHz to 100 GHz. The default setting is 0 Hz.
Remote command:
[SENSe:]FREQuency:OFFSet
on page 644
7.4.3 Keeping the Center Frequency Stable - Signal Tracking
If the signal drifts on the display but you want to keep the center frequency on the sig-
nal peak, the center frequency can be adjusted automatically using
signal tracking . In
this case, the signal trace is surveyed in a specified bandwidth around the expected
center frequency. After each sweep, the center frequency is set to the maximum signal
found within the searched bandwidth. If no maximum signal above a defined threshold
value is found in the searched bandwidth, the center frequency remains unchanged.
Frequency and Span Configuration