Hello,
I've got an SSA 3031X which, according to its datasheet and confirmed by several tests that I've found in this blog and somewhere else, should have a phase noise of around 98 dBc/Hz @ 10 KHz offset (specified with 1GHz input signal).
The problem is I can't get better than 85 dBc/Hz as seen in the attached picture.
The tests conditions are:
Unit: SSA 3021X Plus
SW ID: 3.2.2.5.1R1
Source: Siglent SDG 2042X
Input signal: 0 dBm, 10MHz
Span: 50 KHz
RBW: 100 Hz
VBW: 1Hz
15 Averages
Despite the datasheet test conditions being with a 1GHz input signal, several posts in this blog confirm the stated phase noise using input signals of 10 or 20 MHz.
I don't know whether the fact that my unit has been hacked has somehow messed up the internal PLL parameters that shape its phase noise, I have a defective unit or there's something else I'm doing wrong. Still, I've tested with multiple configurations (RBW and VBW of 1Hz, 20, 30 and 100 MHz input signals, etc) and I always measure no less than 85 dBc/Hz phase noise.
Do you have any clue?
Thanks in advance,
Angel.