Xref: utzoo comp.dsp:1557 sci.electronics:19368 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!sdd.hp.com!spool.mu.edu!news.cs.indiana.edu!uceng!schriste From: schriste@uceng.UC.EDU (Steven V. Christensen) Newsgroups: comp.dsp,sci.electronics Subject: Re: DSP project Message-ID: <8078@uceng.UC.EDU> Date: 17 Apr 91 02:35:18 GMT References: <6354@videovax.tv.tek.com> Followup-To: comp.dsp Organization: Univ. of Cincinnati, College of Engg. Lines: 35 On a related (well, sort of) note, regarding Electronic Guitar Tuning, that was precicely what our first Electronic Design project was this quarter. And let me tell you, that it is mucho difficult to quantify a vibrating guitar string without resorting to DSP technology (we were using strict analog). It was basically a mic, and amp, a filter to get rid of hi-freq garbage, and then the most futile attempt at a half-a-dozen methods to get a good signal to send to a freq-voltage converter (to determine if a string is in tune or not). Depending on 1) how the string was plucked, 2) where it was plucked, 3) how hard it was plucked, 4) how in-tune it already was, and 5) the phase of the moon, we got different results. Harmonics were popping in and out of the signal as the string amplitude diminished, and I can under- stand 1), 2) and 3) for this cause. Most surprizing was 4): Apparently there are natural harmonic resonating frequencies of the body of the guitar which heighten or dampen various harmonics. It also changed depending on how I dampened the vibration of the guitar with my body. All in all, a very frustrating project! Now to write up the report and explain why it didn't work 100%.... Steven Christensen Univ. of Cincinnati -- Steven V. Christensen U.C. College of Eng. schriste@uceng.uc.edu For the adventurous: svc@elf0.uucp