I just published this video on Youtube, to show the performance of ADF4350/ADF4351 based devices with the VMA Simple Spectrum Analyser software:
The main interest of this video consists in showing the refresh rate of the live spectrum using the 35MHz/138MHz-4.4GHz "USB SMA Source/Signal Generator/Simple Spectrum Analyzer" or NWT4000-1/2/3 devices with my software.
Attached to the device is a sinal cable featuring the NOS (TVCABO) CATV service from 138MHz to 750MHz.
During the video, I change from 500 samples to 250, 200, 100 and 1000 samples, back and forth. Notice the relevant RBW.
At the end of the video I zoom in by reducing the frequency span. This shows how high a resolution on can achieve.
For a device you can purchase for as little as 60 Euro, this is quite a performance!