3.4 Raised cosine filtering

Raised cosine filter family

Examples
Example 3.1
Questions
Question 3.3
Question 3.4
Matlab



A commonly used realization of the Nyquist filter is a raised cosine filter, so called because the transition band (the zone between passband and stopband) is shaped like part of a cosine waveform.

The sharpness of the filter is controlled by the parameter a, the filter roll-off factor. When a = 0 this conforms to an ideal brick-wall filter.

 

The bandwidth B occupied by a raised cosine filtered data signal is thus increased from its minimum value, Bmin = 0.5 X 1/Ts, to:

Actual modulation bandwidth, B = Bmin(1 + a)