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From: markp on 3 Apr 2010 16:04 "Phil Hobbs" <pcdhSpamMeSenseless(a)electrooptical.net> wrote in message news:4BB799A7.1050805(a)electrooptical.net... > �Leo� wrote: >> On 2 abr, 01:27, "JosephKK"<quiettechb...(a)yahoo.com> wrote: >>> On Thu, 1 Apr 2010 14:50:33 -0700 (PDT), �Leo� <leo2...(a)gmail.com> >>> wrote: >>>> On 30 mar, 22:53, "JosephKK"<quiettechb...(a)yahoo.com> wrote: >>>>> On Sat, 27 Mar 2010 10:00:39 -0700 (PDT), �Leo� <leo2...(a)gmail.com> >>>>> wrote: >>>>>> On 26 mar, 12:23, �Leo� <leo2...(a)gmail.com> wrote: >>>>>>> I want to make a circuit that takes aguitarinput signal, and then >>>>>>> outputs a signal with fundamental and 2nd order harmonic with the >>>>>>> same >>>>>>> level (or arbitrary levels, I want to amplify the two components at >>>>>>> will). >>>>>>> I figured that there are various ways to do this, but I'm trying to >>>>>>> do >>>>>>> it all analog if possible (since it usually produces more pleasant >>>>>>> sounds). Plus there are already commercial digital octave doublers, >>>>>>> and the ones that are analog come as ring modulators (they add more >>>>>>> components 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 signal >>>>>>> through a emitter follower stage, biased so the amplification is >>>>>>> sufficiently non-linear to produce 2nd order harmonic distortion >>>>>>> (and >>>>>>> a little 3rd). Then to isolate the 2nd harmonic, I thought of >>>>>>> inverting the input through another signal path and then adding the >>>>>>> two signals, and hope that the fundamental frequency cancels out. >>>>>>> While trying to do this in spice, I realized that I'm going to have >>>>>>> to >>>>>>> have some kind of AGC so the two signals hace the same component of >>>>>>> the 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. >>>>>> In response to all: >>>>>> Thanks for the ideas. Some of them are much too complicated or >>>>>> expensive for the scope I was aiming at. >>>>>> The simple techniques with spurious frequencys are already >>>>>> implemented, and the circuits are available on the web, so I don't >>>>>> think I would try reinventing the wheel. >>>>>> I was just trying to implement my original idea, but it doesn't seem >>>>>> to be an easy task and I don't think it would be reliable in the end. >>>>>> So, could I arrive to the conclusion that getting a 2nd order >>>>>> harmonic >>>>> >from an audio source is not a trivial task (with as little distortion >>>>>> as possible)? >>>>> I have an idea that is all analog and just reachable for DIY. I need >>>>> to >>>>> set up a simulation and see if i can get it to do what i think it >>>>> will.. >>>>> If it works the way i think it might, it will do a real neat octave >>>>> trick. >>>>> I'll be back when i get my SPICE simulation done. >>>> Any progress ? >>> I was figuring on working it this weekend (Apr 3/4 and maybe more). Do >>> you have >>> LTSpice? If so, then i could post that file for you without dragging >>> you to >>> alt.binaries.schematics.electronic for image files. >> >> I do, in fact LTSpice is my favorite SPICE program. > > It's everyone's favourite, except for Jim Thompson--and he's just mad > because the license forbids using it to design ICs. ;) > There is a less well known Spice simulator from Diodes/Zetex that seems to have simular functionality and ease of use: http://www.diodes.com/zetex/?ztx=3.0/design_simulator_02 Mark.
From: Jim Thompson on 3 Apr 2010 18:35
On Sat, 03 Apr 2010 15:40:23 -0400, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >�Leo� wrote: >> On 2 abr, 01:27, "JosephKK"<quiettechb...(a)yahoo.com> wrote: >>> On Thu, 1 Apr 2010 14:50:33 -0700 (PDT), �Leo� <leo2...(a)gmail.com> wrote: >>>> On 30 mar, 22:53, "JosephKK"<quiettechb...(a)yahoo.com> wrote: >>>>> On Sat, 27 Mar 2010 10:00:39 -0700 (PDT), �Leo� <leo2...(a)gmail.com> wrote: >>>>>> On 26 mar, 12:23, �Leo� <leo2...(a)gmail.com> wrote: >>>>>>> I want to make a circuit that takes aguitarinput signal, and then >>>>>>> outputs a signal with fundamental and 2nd order harmonic with the same >>>>>>> level (or arbitrary levels, I want to amplify the two components at >>>>>>> will). >>>>>>> I figured that there are various ways to do this, but I'm trying to do >>>>>>> it all analog if possible (since it usually produces more pleasant >>>>>>> sounds). Plus there are already commercial digital octave doublers, >>>>>>> and the ones that are analog come as ring modulators (they add more >>>>>>> components 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 signal >>>>>>> through a emitter follower stage, biased so the amplification is >>>>>>> sufficiently non-linear to produce 2nd order harmonic distortion (and >>>>>>> a little 3rd). Then to isolate the 2nd harmonic, I thought of >>>>>>> inverting the input through another signal path and then adding the >>>>>>> two signals, and hope that the fundamental frequency cancels out. >>>>>>> While trying to do this in spice, I realized that I'm going to have to >>>>>>> have some kind of AGC so the two signals hace the same component of >>>>>>> the 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. >>>>>> In response to all: >>>>>> Thanks for the ideas. Some of them are much too complicated or >>>>>> expensive for the scope I was aiming at. >>>>>> The simple techniques with spurious frequencys are already >>>>>> implemented, and the circuits are available on the web, so I don't >>>>>> think I would try reinventing the wheel. >>>>>> I was just trying to implement my original idea, but it doesn't seem >>>>>> to be an easy task and I don't think it would be reliable in the end. >>>>>> So, could I arrive to the conclusion that getting a 2nd order harmonic >>>>> >from an audio source is not a trivial task (with as little distortion >>>>>> as possible)? >>>>> I have an idea that is all analog and just reachable for DIY. I need to >>>>> set up a simulation and see if i can get it to do what i think it will.. >>>>> If it works the way i think it might, it will do a real neat octave trick. >>>>> I'll be back when i get my SPICE simulation done. >>>> Any progress ? >>> I was figuring on working it this weekend (Apr 3/4 and maybe more). Do you have >>> LTSpice? If so, then i could post that file for you without dragging you to >>> alt.binaries.schematics.electronic for image files. >> >> I do, in fact LTSpice is my favorite SPICE program. > >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 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 -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy |