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.
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".
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.