This application note describes the fundamentals of pulse shaping and the tradeoffs associated with the design of digital pulse-shaping filters.
The note introduces pulse‑shaping techniques used to limit bandwidth while minimizing decoding errors in data‑transmission systems. It covers the basic rectangular pulse, its spectrum, and the raised‑cosine filter that provides controlled bandwidth containment.
It then discusses digital implementation issues, including FIR vs. IIR architectures, the impact of roll‑off factor (α), oversampling factor (M), and the number of symbols spanned (D). Several surface‑plot groups illustrate filter error at the pass‑band edge, Nyquist frequency, and stop‑band attenuation.
Pulse shaping limits the signal bandwidth while minimizing decoding errors at the receiver.
D defines the number of symbols spanned by the impulse response of the filter.
FIR filters are preferred because they can be designed with linear phase response and are intrinsically stable.