At 07:35 AM 5/19/2004, Scott Dattalo wrote: >On Tue, 18 May 2004, Dwayne Reid wrote: > > > This isn't what you want, but if you limited it to 2 channels of 8 bit > > data, you could do the classic > > > > movfw inputA ;add inputs A&B, result in inputB > > addwf inputB,F ;9 bit sum, inc C > > rrf inputB,F ;/2 > > > > This, of course, is limited to 2 channels. > >I'm neither a DSP or Audio guru, but this can't be right. Suppose one of >the streams is quiet. This combination will attenuate the other. Simple >analog mixers work somewhat similar to this, however they have more >dynamic range. So boosting the mixed (and attenuated) output has less >degradation on the signal then chopping off one of the bits on an 8-bit >digital signal. I would be more inclined to sum the streams together and >clip the results. I'm much more an analog guy rather than digital and have fairly limited DSP experience. But analog mixers work in a similar fashion. Look at it this way: you want to maximize your Signal to Noise Ratio. So: you choose your components such that when all inputs have their maximum input signal applied, the mixer stage output is just below clip. For a 2 input mixer, each input contributes 50% of the output. If one input goes away, the output drops by half. The problem with clipping the signal is that it sounds just awful. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 20 years of Engineering Innovation (1984 - 2004) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body