From analogue-request@magnus.acs.ohio-state.edu Fri May  7 12:19:24 1993
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Date: Fri, 7 May 93 09:16:33 PDT
From: till@lucid.com (Don Tillman)
Message-Id: <9305071616.AA04949@acid-rain.lucid.com>
To: analogue@magnus.acs.ohio-state.edu
In-Reply-To: <RICK@SARA.NL>'s message of Thu, 6 May 93 06:43:51 -0400 <9305061043.AA21087@quark.magnus.acs.ohio-state.edu>
Subject: Pitch To Voltage converter
Reply-To: till@lucid.com
Status: OR

[Rick, ignore the previous message I sent, I goofed up the To: line
and sent it to you only.]

   Date: Thu, 6 May 93 06:43:51 -0400
   From: <RICK@SARA.NL>
   Date: Thu, 06 May 93 12:42:08 N

   I'd be grateful if anyone could direct me to the schematic of
   a pitch-to-voltage converter. Or even a general idea of how they
   work.

Well, you haven't told us anything specific about how you want to use the
PtV converter so you'll get some answers that won't be applicable.

What do you want to use it for?
What's the frequency range you want to cover?
What's the input signal look like?
How fast does the conversion have to work?
How accurate does the conversion need to be?
Do you want a linear or a log output?

   From: Peter Cassidy <peterc@comm.mot.com>
   Date: Thu, 6 May 93 15:07:11 BST

   OK. Here's one, straight from the R.S catalog:

I don't know anything about this one (it's not in my Radio Shack catalog)
so I can't comment.

   Date: Thu, 06 May 93 10:34:08 -0400
   From: Yoshiaki_Ohshima@SPEECH1.CS.CMU.EDU

   i think f-to-v converter ic's are commercially available.
   but i'm not certain if they are to your need. so i speak
   of things in general.
      the principle is, if i recall correctly, trigger a one shot
   pulse (like 555) by the edges of the frequency counter output 
   (like the one you use in the octaver or the divider circuit) and 
   integrate it. the read out from the integrator capacitor tracks 
   the number of pulses with a certain time constant to your spec.

True enough, but these devices won't be too useful for electronic music
work (I'm guessing that's the context of Rick's request).  For instance, if
there's any grunge or noise in the input signal, then the output voltage
will be way off.  There are far better methods like using a phase locked
loop or digitally counting the time between pulses.

      for some instruments such as guitars, building a reliable	
   frequency counter is not easy. 

Absolutely!  For guitars the signal waveform is very ragged and constantly
changing (string harmonics are almost never integral multiples of the
fundamental and the harmonic conent changes drastically depending on how
you play and what note you're playing), the waveform level is all over the
place, and guitarists generally do not play very cleanly.  Also there's a
need for the conversion to take place in a cycle or two.  Certainly
difficult.
				  
 -- Don


From analogue-request@magnus.acs.ohio-state.edu Thu May  6 12:22:58 1993
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Date: Thu, 6 May 93 11:15:43 EDT
Original-From: aluxpo!wbf (William Fox)
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To: analogue@magnus.acs.ohio-state.edu
Subject: Re: FTV
Status: OR

Subject: Re: FTV converter

I'm not familiar with the device that Peter suggested.  In the past, I
noticed that many F-to-V chips required a pulse input.  This may be
derived by low pass filtering your source (you can play with that) and
then use a comparator to do zero crossing detection.  Apply this pulse
to the F-to-V chip.  I make no claims as to usefulness.

Bill Fox

From analogue-request@magnus.acs.ohio-state.edu Thu May  6 11:23:23 1993
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Date: Thu, 6 May 93 11:15:43 EDT
Original-From: aluxpo!wbf (William Fox)
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To: analogue@magnus.acs.ohio-state.edu
Subject: Re: FTV
Status: OR

Subject: Re: FTV converter

I'm not familiar with the device that Peter suggested.  In the past, I
noticed that many F-to-V chips required a pulse input.  This may be
derived by low pass filtering your source (you can play with that) and
then use a comparator to do zero crossing detection.  Apply this pulse
to the F-to-V chip.  I make no claims as to usefulness.

Bill Fox

From analogue-request@magnus.acs.ohio-state.edu Thu May  6 07:00:07 1993
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From: Peter Cassidy <peterc@comm.mot.com>
Subject: Re: pitch to voltage
To: RICK@sara.nl
Date: Thu, 6 May 93 11:55:41 BST
Cc: ANALOGUE@magnus.acs.ohio-state.edu (Analogue Mail List)
In-Reply-To: <9305061043.AA21087@quark.magnus.acs.ohio-state.edu>; from "RICK@sara.nl" at May 6, 93 6:43 am
Mailer: Elm [revision: 66.25]
Status: OR

> From: Rick Jansen <RICK%SARA.NL@OHSTVMA.ACS.OHIO-STATE.EDU>
> 
> 
> I'd be grateful if anyone could direct me to the schematic of
> a pitch-to-voltage converter. Or even a general idea of how they
> work.
> 
> Rick Jansen
> --
> rick@sara.nl
> 

This sounds like an interesting project. Have you looked at F-V convertor
IC's (Freq to voltage convertors). They're commonly available. I'll have
a look at specs, prices. There is a schematic available in the RS Data 
Library. I'll bring it in tomorrow from home !!

--
Regards,

Peter

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|                  M O T O R O L A   B . V .   I R E L A N D                 |
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| Peter Cassidy - T.S.E Dublin        | Phone : 353-1-840-8866  Ext. 417     |
| MACCVM  : C10404                    | X400  : peterc@comm.mot.com          |
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From analogue-request@magnus.acs.ohio-state.edu Thu May  6 06:44:11 1993
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);
Message-Id: <9305061142.AA108610@diamond.sara.nl>
To: analogue@magnus.acs.ohio-state.edu
Subject: PTV - Pitch To Voltage converter
Date: Thu, 06 May 93 12:42:08 N
From: Rick Jansen <RICK%SARA.NL@OHSTVMA.ACS.OHIO-STATE.EDU>


I'd be grateful if anyone could direct me to the schematic of
a pitch-to-voltage converter. Or even a general idea of how they
work.

Rick Jansen
--
rick@sara.nl

  She's a module and she's looking good


