PLL Pitch to Voltage Converter

[StephenGiles]

Did you test it with an electric guitar? This is the acid test, because as mentioned frequently, and as I'm sure you are aware, the guitar signal goes all over the place as it decays, so unless proper guitar signal conditioning is used - compression and fundamental extraction, there are frequency tracking problems.

[dj_death]

Not yet Stephen, yes i know how rich in harmonics and how complicated a guitar signal can be. I have used many times electronic guitar tuners and i saw how difficult it was to track only single notes. I don't know how is it going to perform. It's only an idea that if it's tested and working PERHAPS it will give better results than the other frequency to voltage techniques. These fundamental extractors you mentioned are really interesting circuits. First the one at Boss DF2 looks more straight forward and easy to build than the monster is used in Eh Guitar Synth whitch i think it uses difficult to find parts. Do you have an idea which is better do you have any experience in these? If i understand well a Complete guitar - pitch to voltage converter consists of these parts: Fundamental Extractor - Frequency to voltage converter - Filter and Hold - Maybe a logarithmic amplifier if it's needed.

Gez how did you use your f2v circuit? Some part values are missing. Did you use it to control a vco through guitar?

[gez]

Gez how did you use your f2v circuit? Some part values are missing. Did you use it to control a vco through guitar?

The only thing missing is the details of the constant current source.  You'd be better off with a dedicated device, but a simple PNP transitor can be used, though linearity won't be as good.

I used it in as part of an octave up circuit.  For my purposes it didn't have to be that linear and the guitar signal didn't have to be that pure.  It worked really well: I got a square wave one octave up with 50:50 duty cycle and there was no latency or problems with tracking, though the range was a little limited as I didn't use the right op-amp (need to use one with common mode voltage range including earth)...probably could have done with a slightly higher supply too. 

I didn't build it in the end, it needs more work doing to it.

[StephenGiles]

http://rubidium.dyndns.org/cag/pdf/electrax.pdf

have you seen this ?

[slacker]

Very nice, theres some interesting things in there apart from the PLL stuff.
I don't know if this is any use, but whilst looking for info about the Steiner VCF I found this "guitar synth" that appears to have pitch tracking.
http://yusynth.net/Modular/Commun/STEINERVCF/gtr-synth.jpg

[gez]

Very nice, theres some interesting things in there apart from the PLL stuff.
I don't know if this is any use, but whilst looking for info about the Steiner VCF I found this "guitar synth" that appears to have pitch tracking.
http://yusynth.net/Modular/Commun/STEINERVCF/gtr-synth.jpg

I haven't breadboarded the above circuit circuit and I haven't used the LM2907, but I have messed around with its sister chip the LM2917.  They basically use a charge pump design to do the f-to-v conversion and are generally sluggish, especially with large frequency swings (anything up to a second or two to adjust if you want a low ripple output).   Personally, I wouldn't use it...but each to their own! 

[slacker]

I thought it was probably too good to be true