Maker Pro
Maker Pro

Converting 1/v per octave to relative wavelength for hybrid VCO

Erich Pfister

Sep 14, 2015
1
Joined
Sep 14, 2015
Messages
1
Hey All,
I've got a design that will output a pulse every N clock cycles, where N is specified by an A/D converter. As such, the frequency of the pulse generating VCO is defined as Fclock/N. Does anyone know a relatively temperature stable way to calculate N = 2^(-x)? As a programmer, because I want my VCO to operate at 1 volt per octave, the obvious solution seems to be scaling my input - but I don't know if that assumption holds for physical hardware. I imagine this would take the form of some sort of exponentiator, but I do not know if hardware exponentiators will function with negative exponents.

Thanks in advance,
-Erich
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,681
Joined
Nov 17, 2011
Messages
13,681
There are electronic exponentiator circuits, however getting them to work stable over a range of input voltages and temperature is a bit tricky.
Since you alreadyy are in the digital domain (between ADC and VCO), why not insert a little controller (PIC, AVR...) in between and let the controller do the curve fitting/exponentiation as required before passing the ADC data on to the VCO?
 
Top