Guitar one octave Up

=?ISO-8859-1?B?q0xlb7s=?= · 2010-03-26T15:23:12+00:00

I want to make a circuit that takes a guitar input signal, and thenoutputs a signal with fundamental and 2nd order harmonic with the samelevel (or arbitrary levels, I want to amplify the two components atwill).I figured that there are various ways to do this, but I'm trying to doit all analog if possible (since it usually produces more pleasantsounds). Plus there are already commercial digital octave doublers,and the ones that are analog come as ring modulators (they add morecomponents to the signal). The frequency range is 20hz-20khz at worst,the available DC source is 9V.I'm trying to get the 2nd order harmonic by taking the input signalthrough a emitter follower stage, biased so the amplification issufficiently non-linear to produce 2nd order harmonic distortion (anda little 3rd). Then to isolate the 2nd harmonic, I thought ofinverting the input through another signal path and then adding thetwo signals, and hope that the fundamental frequency cancels out.While trying to do this in spice, I realized that I'm going to have tohave some kind of AGC so the two signals hace the same component ofthe fundamental. Designing the AGC has been rather complicated so far.So the idea that i had is getting a little bit complicated.Any help or new ideas would be appreciated.

Mar 26, 2010 42 Replies

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Phil Hobbs 16 years ago

have

It's everyone's favourite, except for Jim Thompson--and he's just mad because the license forbids using it to design ICs. ;)

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net

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markp 16 years ago

There is a less well known Spice simulator from Diodes/Zetex that seems to have simular functionality and ease of use:

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Mark.

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Jim Thompson 16 years ago

have

Not hardly. LTspice post-processing is ugly, gross and not conducive to "pretty" design review reports. Go try out PSpice Probe sometime... then come back and tell me what/why/where/how the right way is done :-)

But LTspice is good at simulating LTC-specific parts :-) ...Jim Thompson

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