tim, one more thought:
the PFB FIR in front of the FFT dominates the latency of the PFB/FFT. the PFB has latency of (Ntaps-1) x FFTlength / Nparallelinputs. a four tap PFB has about three times the latency of the FFT, so if you remove the PFB you will cut latency down by about a factor of three (assuming you remove the corner turn in the FFT). you can also put more inputs in parallel, as i mentioned in my previous email, to cut latency down by factors of 2, 4, 8,... best wishes, dan
