[sdiy] Tempo/Clock-to-CV conversion

[Tom Wiltshire]

On 30 Oct 2007, at 16:46, Needham, Alan wrote:

>
> Florian Anwander wrote:
> ...[snip]...
>> My first idea looks like that:
>> A binary counter is counting down at a fixed rate. The output of the
>> counter is D/A converted (resistornetwork), and the resulting voltage
>> feeds a S&H stage.
>> The positive edge of the incoming clocksignal clocks the sample&hold
>> and (a little bit delayed) resets the counter.
>
> How about just latching the binary down-counter's value at 'RESET'
> and using the latch to drive a DAC, every clock period is measured,
> no S&H drift to worry about
> A nice little microcontroller project (a single-chip solution) ?

Yes, you could definitely do it on one chip like that. You'd need a  
timing counter that measured the time between incoming rising edges  
of the clock. When an edge arrives, you send the last value to a DAC  
(or a PWM output to keep it on one chip), and reset the counter for  
next time.


>> Pulse length will be converted too (to quite short pulses).
>
> Is this a second conversion, one of period, one of pulse width ?

An important question. It'd be easy enough to also keep track of  
falling edges, in order to measure the pulse time too.
Obviously a second PWM output or DAC would be required to output this  
extra information.

Tom