Noise Bandwith for PCSGU250 Spectrum Analyzer

Instruments PC Oscilloscopes and Recorders
1

I am attempting to use the spectrum analyzer function in the PCSGU250 to measure phase noise. However, I need to know the noise bandwidth of the spectrum analyzer. The noise bandwidth is a function of the span, number of FFT points, and the window type. I have been subtracting the measured value in dBV/root(Hz) from the dBV value but the numbers I get do not produce measurements that agree with a similar noise measurement made by an HP3561A FFT dynamic signal analyzer. The PCSGU250 agrees with the HP3561A when I measure tone signals. Has anyone had any experience measuring noise and determining the noise bandwidth?

Thanks for your help.
Dennis Sweeney
VA Tech
Blacksburg, VA

2

Have you checked the PCSGU250 Help->Oscilloscope Help ?
There in the section “Spectral Density marker” is written:
“Using the Spectral Density marker and the Frequency marker, the voltage spectral density (V[size=85]SdBV[/size]) and the noise bandwidth (B[size=85]N[/size]) can be read from the spectrum analyzer display.”
Anyhow, I’m afraid this option is not what you are looking for…