Signal Processing for Communication Systems
Modified duobinary is the partial-response cousin of duobinary that puts a spectral null at DC. It correlates symbols two baud intervals apart, so the controlled ISI sits on the alternate sample rather than the neighbour. The Nyquist zero-ISI condition is relaxed to The minus sign at lag \(2T\) is what opens the null at DC. … Read more
Why FFT bins leak when tones miss bin centers, what scalloping loss is, and how windowing + ENBW trade leakage against noise bandwidth.
This post contains interactive python code which you can execute in the browser itself. The moving average filter is a simple Low Pass FIR (Finite Impulse Response) filter commonly used for smoothing an array of sampled data/signal. It takes \(L\) samples of input at a time and takes the average of those \(L\)-samples and produces … Read more
BPSK maps bits to opposite phases; coherent demodulation, decision rule, and links to the Q-function BER formula and interactive calculator.
Gibbs phenomenon: why partial Fourier sums overshoot near jumps, that the overshoot does not vanish with more terms, and a visual demonstration.