Agilent Technologies N9340A - Manual (Page 63)

Making Measurements 4
N9340A User’s Guide 61
Measuring Phase Noise
Phase Noise is a frequency domain measure of
stability. We specify phase noise as single sideband
power in relation to the fundamental RF output
frequency, and measured at various offset
frequencies from the carrier, normalized to a one
hertz measuring bandwidth.
1 Press [PRESET].
2 Input a signal (50 MHz, 0 dBm) to the analyzer
RF IN connector.
3 Set the center frequency, span:
•
Press
[FREQ] > {Center Freq} > 50 > {MHz}.
•
Press
[SPAN] > 100 > {MHz}.
4 Set the average mode to RMS
•
Press
[BW/SWP] > {Avg Type} > {Power}
•
Press
[TRACE] > {More (1 of 2)} > {Detection} (Man)
> {Average} (RMS)
5 Turn on a marker and place it on the peak of
the signal.
•
Press
[MARKER] to active Marker 1
•
Press
[MARKER] > {Peak Search}
6 Set the frequency offset for you to measure the
Phase noise.
•
Press
[MARKER] > {Delta}, then set the
frequency of the delta marker to 30 MHz
7 Average the trace.
•
Press
[TRACE] > {More (1 of 2)} > {Average} (On)
and set the average number to 40 using the
numeric keypad.
The value of marker delta displays in the upper
right corner of the display. Then you can calculate
the value of the phase noise by
Phrasenoise a RBW log – =