Re: [Ngspice-users] Instantaneous frequency

[Patrick K. <p....@po...>]

To Holger Vogt and Daniel Marks:

Thanks for you quick advice on this question. Sorry for the delayed
response. I had to work on other issues so I did not have to time to
look into this more than superficially. I will check out what you have
recommended and let you know the outcome. I am still busy with other
things (I also have a tape-out coming up, that does not help :D), so it
might be a while. I just wanted to let you know that I did not simply
ignore your messages.

Thanks, kind regards,
Patrick

On Sat, 2026-02-07 at 15:55 +0100, Holger Vogt wrote:
> You are asking for a 'simple' way. Simplicity here depends on your 
> background know-how.
> 
> You might use a circuit for the frequency measurement.
> 
> In the ngspice distribution we offer a pll (phase locked loop)
> circuit 
> (
> https://sourceforge.net/p/ngspice/ngspice/ci/pre-master-46/tree/exampl
> es/xspice/pll/), 
> which probably could serve this task, but needs to be adapted to your
> requirements (center frequency, frequency deviation).
> 
> You might google for FM (frequency modulation) detectors.
> 
> A (zero crossing) function may probably be constructed with
> behavioural 
> sources like the B source (manual chapter 5). But this is tricky, as
> the 
> transient simulation uses non-constant time steps, and the chosen
> time 
> steps will not be exactly at the crossing. So one needs a sort of 
> interpolation.
> 
> If you are fit in C programming, you might program a code model 
> (examples are described in chapter 8 of the manual) to fulfill
> exactly 
> your requirements.
> 
> 
> 
> 
> _______________________________________________
> Ngspice-users mailing list
> Ngs...@li...
> https://lists.sourceforge.net/lists/listinfo/ngspice-users