Live Q&A with fred harris - Green FIR Filters with Large Ratio of Sample Rate to Bandwidth

adam,

The polyphase filter that implements a cascade of analysis and binary masked synthesis filter bank always has a longer delay that the direct FIR filter implementation... because you have gone through two filters between input and output....

What is interesting, there is a recursive form of the polyphase filter, one with non uniform phase and one form with linear phase (actually equal ripple approximation to linear phase) the linear phase version will present a reduced delay relative to the direct form FIR.... see my book and if interested... I can pass along the code for the M-Path Linear phase IIR filter bank...

Prof. Harris,
would it be possible to get the code for the M-Path Linear phase IIR filter bank

thanks

Can polyphase FIR filter design reduce delay compared to a non-polyphase FIR filter?

Boy did you bury the lead in the last few minutes!
So for a log spaced polyphase bank, do you keep the transition bandwidths equal to assure the 6 dB Nyquist overlap but scale the bandwidths by the square root multiplier? Wouldn't that lead to a varying number of coefficients for each polyphase bank?

thank you so much for great presentation dr harris ! I'm curious to learn more about polyphase filterbank for hearing aids which is topic of your upcoming paper, but did not catch when/where will it be published. also, some specifics about inband aliasing that might affect some processing like echo-canceller, etc...
thanks & best regards !

Hi Fred,
It is always an immense pleasure listening to your talks.
Regarding RF direct sampling, what are your thoughts about one analog Hilbert transformer followed by 2 ADCs, rather than directly sampling RF with one ADC? With the first approach we would have the 2 ADCs running at half speed but never seen a system done in this way so far.
Thanks!
Stefano