Raised-Cosine and Root-Raised-Cosine Formulas

Raised-Cosine (RC) and Root-Raised-Cosine (RRC) filters are commonly used in digital data modems. Here, we provide design formulas for these filters.


  • Each version of the same formula is algebraically equivalent; they just use different parameters.
  • The impulse response formulas include a "sinc(x)" term, that is, "sin(x)/x". Although "sinc(0)" seemingly includes a divide-by-zero, L'Hospital's rule indicates that the numeric value of sinc(0) is 1.0.

The Culture of comp.dsp

As best anybody can tell, the comp.dsp newsgroup doesn't have a charter which describes what it is supposed to be. But if you think of a newsgroup as a "cocktail party", what really matters is not its "charter" but its "personality", that is, its "culture".

How to Search the comp.dsp Archives

the unofficial comp.dsp home page

You can search the comp.dsp archives via Google's "Group" search features. Google provides two search interfaces: a basic search and an advanced search.

A Call for Tricks

the unofficial comp.dsp home page

On April 17, 1999, in the post below, Rick Lyons issues "A Call for DSP Tricks":

Well Guys,

We have a plan on how we'll collect, compile, and display any clever DSP Tricks that you'd like to share with other DSP practitioners.

Usenet terms, acronyms and symbols

the unofficial comp.dsp home page

Here we define some terms, acronyms and symbols which commonly appear on Usenet


Here are a few important Usenet terms (borrowed from the The New Hacker's Dictionary).

the unofficial comp.dsp home page

the unofficial comp.dsp home page


comp.dsp is the Usenet newsgroup devoted to sharing information about Digital Signal Processing. Here, dspGuru provides information for all things comp.dsp.

Digital Filter Terminology

From: R. G. Lyons, UNDERSTANDING DIGITAL SIGNAL PROCESSING, (Appendix F - pages 494-505). © 1997 by Addison Wesley Longman Inc., Reproduced by permission of Addison Wesley Longman. All rights reserved.

The first step in becoming familiar with digital filters is to learn to speak the language used in the filter business.

Syndicate content