A highpass filter filters out low frequencies. This is again an impulse invariant design of a first order section. Up to four (=N) sections can be cascaded. Right outputchannel is original minus highpass filtered signal. The sections are implemented with floating point calculation, this reduces the possible quantization in the filter. Downside is it takes more CPU cycles.
hp1transfer.png simulated with Matlab V5.3:
-- ChristiaanGelauff - 30 Jan 2006