I am using a Keysight InfiniiVision MSOX3054T Scope having Bandwidth of 500MHz and Sampling rate of 5Gsa/s.
I am learning to use the FFT Option in the scope.
Below is the waveform I captured of my QSPI Clock signal (48MHz)
My start frequency is 30MHz and Stop Frequency is 60MHz.
What is the threshold and the excursion levels (marked in red) mean? How to play around this value?
And how is the -4.97dBV calculated (again marked in red)? Can someone show the calculation for the -4.97dBV value?