[sdiy] (Low) frequency to voltage conversion

[Neil Johnson]

Steve Lenham wrote:
> However, the OP was asking about frequency-to-voltage conversion, not the
> other way round - does that make any difference, or is it equally achievable
> in the analogue domain?

Oh, right, yeah, analogue F/V conversion at such low frequencies will
take a VERY long time due to filtering you'd need to avoid ripple, as
you say.
In that case do what Tom was talking about a few days ago on another
thread and implement a reciprocal frequency counter in a PIC/AVR/etc,
and then output a voltage via a DAC proportional to the input
frequency (insert usual discussion about how many bits, etc etc etc).
That way you only have to wait for one complete cycle before the
output updates.  Getting it to behave nicely over a 10 octave range
will be fun.

Neil
--
http://www.njohnson.co.uk