[sdiy] understanding this one transistor F to V

[Magnus Danielson]

Eric Brombaugh wrote:
> 
> On Nov 3, 2009, at 4:24 AM, René Schmitz wrote:
> 
>> Eric Brombaugh schrieb:
>>> Sure looks like a simple flip-flop divider to me.
>>
>> But thats not a FF but an astable oscillator.
> 
> Well, yes. I've heard the cross-coupled circuit on the right called an 
> 'astable flip-flop', so let's split the difference. My point though is 
> to clarify for the OP that the way this circuit is set up there is no 
> explicit conversion from frequency to voltage. Instead, the input signal 
> is amplified and drives the supply lines of the astable flip-flop in 
> such a way that the result is to divide the input signal's frequency by 
> two.

It's essentially an injection locked divider. It synchronises either 
side of the divider, whichever side is near synchronisation. The V-F 
action just offsets the frequency, but essentially it is synchronised.

> At least that was my thought based on a quick glance at the circuit. If 
> you've got a different interpretation I'd be interested to hear it.

You've got it.

Cheers,
Magnus