Why does spectrum block change the initial parameter unit?

Answer 1

[Rhea Chandy]

The fft (Fast Fourier Transform) block that you're using, along with the Spectrum Analyser, outputs a frequency spectra of signals the fft signal. As such, it will only accept as input and output the spectrum units (dBm , dBV , dBW , Vrms , Watts).

If you would like to view the signal before the fast fourier transform is applied, I suggest that you connect another Scope block to display the signals you need.