Thank you for your response.
The reference level I am using is 0 dBm.
I ran the ‘niScope SMT Power in Band.vi’ example with dithering enabled and disabled. I could see the noise when dithering was enabled and the reduced noise or no noise when dithering was disabled. See attached .jpg’s. I added ‘Waveform Graph 2’ to display the output of ‘niScope Multi Read Cluster.vi’.
In my application, I disabled dithering and put the trigger level lower. It now works.
Disabling dithering needs to be set after ‘ni5660 Configure for spectrum.vi’. Inside the ‘ni5660 Configure for Spectrum.vi’, a vi called ‘SMT Configure RFSA for Spectrum.vi’ enables dithering. ‘SMT Config niScope for Spectrum.vi’ is another vi that enables dithering.
Thank you for your help.