I'm trying to figure out how to perform N'-band channelizer for SSCA (strip spectral correlation analyzer) via sliding FFT. I understand that I have to take $N$ points of signal in time domain $x(t)$, apply a windowing function and take another $N$ points by shifting the window by $L$ ($L=1$ in my case). Then I apply Fourier transform to those points. But how many of those windowed vectors do I need? I tried to follow code in commP25ssca.m but I can't understand steps between the final result (and then can't set proper input values to the mentioned function).
Documentation for matlab function: https://apps.dtic.mil/sti/pdfs/ADA311555.pdf
My code for simple sliding fft via following this paper: https://www.comm.utoronto.ca/~dimitris/ece431/slidingdft.pdf
clc clear all close all ef = 0.1; ef_vz = 1; Td = 1000; time = 0:1/ef_vz:Td; freq = 0:1/Td:ef_vz; sig = 1*exp(1j*2*pi*ef.*time); spek = abs(fft(sig)); N = 512; num_blocks = floor((length(sig)-N) / 1); x = sig; counter = 0; for i = 1:length(x) k = [i:i+N-1]; window = x(k); if i == 1 Xk(i,:) = fft(x(k)); else Xk(i,:) = (Xk(i-1,:)-x(i)+x(i+N-1)).*exp((1j*2*pi*(k-1))/N); end counter = counter + 1; if counter == 1 break else continue end end p = linspace(0,ef_vz,N); figure(1) plot(p,abs(Xk))