R&S 1322.8003K06, User Manual

Page: 157 / 555

Common Analysis and Display Functions
R&S
®
FSPN
157 User Manual 1179.4363.02 ─ 01
Shows the measured amplitude noise characteristics.
●
"Phase + AM Noise"
Shows the sum of the phase noise and AM noise characteristics.
The "AM Noise" and "Phase + AM Noise" traces are only available for the "Noise Spec-
trum" diagram, and not in its variations ("Noise Spectrum L(f)", "Noise Spectrum
S
Φ
(f)", "Noise Spectrum Sv(f)", "Noise Spectrum Sy(f)").
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:RESult[:TYPE]
on page 416
Smoothing traces
The R&S FSPN allows you to smooth traces and thus remove unwanted anomalies.
You can apply smoothing to all active traces individually (Smoothing "State"), and
define the magnitude of trace smoothing in percent (Smoothing "Value").
The range is from 1% to 20%.
Note : In the spot noise vs tune measurement, trace smoothing properties apply to all
traces.
Remote command:
State:
DISPlay[:WINDow<n>]:TRACe<t>:SMOothing[:STATe]
on page 418
Value:
DISPlay[:WINDow<n>]:TRACe<t>:SMOothing:APERture
on page 417
State (SN vs Tune):
[SENSe:]SMOothing[:STATe]
on page 385
Value (SN vs Tune):
[SENSe:]SMOothing:APERture
on page 384
Shifting the trace
Shifting the trace can be useful to subtract external noise sources from the results. The
trace offset is a visual device that shifts the trace by certain level.
You can apply an offset to all active traces individually (Offset "State"), and define an
offset in dB by which the trace should be shifted.
Remote command:
State:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel:OFFSet:STATe
on page 417
Offset:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel:OFFSet
on page 417
Displaying persistence
The term persistence has its origins in cathode ray tube devices (CRTs). It describes
the time period one point on the display stays illuminated after it has been lit by the
cathode ray. The higher the persistence, the longer you could observe the illuminated
point on the display.
In the phase noise application, the persistence defines for how long a trace remains
visible before it fades away. An event that has occurred a single time is visible for up to
8 seconds. As the statistical frequency of an event gets smaller at coordinates with sig-
nal parts that are not constantly there, the trace fades away.
A signal with constant frequency or phase characteristics does not show the effects of
persistence on the trace. When the frequency or phase of a signal change slightly,
however, the effect of persistence becomes visible through color changes or changes
in the shape of the trace.
Trace Configuration