Hello,
I want to measure the FFT of a clock signal but during measurement I am getting some unwanted result.
I am using a 3 MHz clock signal and perform fft by Measurement -> Spectrum. Sampling frequency = 48M, No of samples = 65536. When I plot it, then in the spectrum I have seen bunch of other spectral line around fundamental and other harmonic frequency with a spacing of 48M/65536 = 732 Hz. As a result the energy of signal is spreading over those spectral lines. Can anyone help me on that? Why do we have bunch of spectral lines with this specific frequency and how to avoid it? I have attached image for understanding of problem. First picture is zoom in picture while second picture is zoomed version of spectral lines at fundamental frequency. I am using "Hanning" window type.
