Transfer function and impulse response of a raised cosine filter
The raised cosine filter is one of the family of
Nyquist filters that satisfy the criteria for zero intersymbol interference.
The transfer function H(f) of a raised cosine filter is given by:

where a is the filter roll-off factor and T is the symbol period of the
message. An a = 0 corresponds
to an ideal brick-wall filter.
The impulse response for a raised cosine filter is given by:
