Signal power vs energy — formulas and Matlab/Python examples
Power vs energy of a signal: finite-energy vs finite-power classification, discrete formulas, and Matlab/Python checks before BER or PSD normalization.
Power spectral Density
White noise in Matlab — generate AWGN, plot PSD, check variance
Simulate white / Gaussian noise in Matlab: generate with randn, verify variance and flat PSD, then reuse the noise model in BER simulations.