DSP

dspGuru is alive and well!
Hi Gang, Welcome back! I haven't been active on comp.dsp for quite awhile, but contrary to a recent report seen here that dspGuru* is a "dead website", I'd like to just say that "reports of its death have been greatly exaggerated": in fact, dspGuru is very much alive and well! Likewise, I, myself, am still... 8 Feb 2006 20:57

OFDM Question
I was wondering about demodulation. We woudl need phase coherence of both the main carrier and the sub-carriers. I assume the main carrier can be locked onto with a PLL but what about the sub-carriers? Do they use a pilot sequency of some sort when multiply up to get the other frequencies? Thanks Tom ... 6 Feb 2006 08:57

MELP / MELPe vocoder and IMBE vocoder
Does anyone have any link or results of speech quality comparison between IMBE vocoder (or AMBE) and MELPe / MELP vocoder at rates 2400, 1200, 600 bps? I heard MELPe vocoder sounds much better, is that true? What about other aspects such as robustness to background noise & channel errors? Claudia R. ... 5 Feb 2006 01:12

Scaling cutoff freq of Butterworth filter
Dear group, I am currently using a butterworth lowpass filter for filtering sets of parameter files. For this purpose, I found an "optimal" cutoff frequency to generate the filter. I have, however, the necessity of changing the "sampling rate" of the parameter set, but at the same time get the "same" results in... 7 Feb 2006 03:36

Sound localisation
I am doing research into sound localisation for a degree project and how to alter signals to affect their apparent position. I understand how and why time delay and amplitude difference between the ears have an effect as well as spectral changes. However I keep finding references to phase differences being an... 2 Feb 2006 19:46

LDPC
Hi I created a common platform for LDPC codes for sharing ideas, research problems, issue discussions, software and neat papers sharing. This is first group of its kind on Google. Feel free to join here: http://groups.google.com/group/LDPC?lnk=li Saad Michigan ... 1 Feb 2006 09:18

Plagiarism
Hi, in October I posted here on comp.dsp that I though that my work had been plagiarised. Thanks to some excellent advice, especially from Rick Lyons, I was able to expedite a swift and satisfactory reaction from IEEE. My allegation was up held and the following notice of violation has been attached to the digi... 6 Feb 2006 04:10

microphone hum
I'm not knowledgeable in DSP, but maybe someone here can help. I have a cheapo electret microphone that is giving a bad hum, at 15754hz and 60hz Any idea for a problem here or a quick fix. It's a cheapo so hopefully you can point me to something simple like installing a new ground or something easy. -- ... 3 Feb 2006 20:44

About spectrum of speech and fax transmission
hi all, Someone please tell me why the spectrum of speech rolls off towards the higher frequencies ?????? I am a newbie to DSP so, simple terms please as far as possible. I am hoping to use this fact to distinguish it from other data transmissions such as fax. (this was suggested to me by Mr.Vladimir Vassil... 9 Feb 2006 10:01

Amplitude response of a Biquad Filter
I have a Guitar effects processor. It has an Equaliser ( five band Biquad filter) This equaliser accepts 5 coefficients I wish to plot a graph of the amplitude versus frequency of this cascaded filter. I am using Excel. Can anyone assist with the formula to generate frequency response of a Biquad filter. ... 23 Feb 2006 09:37