[LAD] simulating analog audio devices

Pieter Palmers pieterp at joow.be
Fri Jun 1 13:46:20 UTC 2007


Robin Gareus wrote:
> Erik de Castro Lopo wrote:
>> Robin Gareus wrote:
>>
>> When Spice loads the libsndfile component, can the component find out
>> the inter-sample period used by Spice? 
> 
> no. Spice does not use a constant interval; else it would be straight
> forward to use libsamplerate.
> 
>> If the above is not possible, I suggest that you up sample the audio 
>> by say 128 times and then linearly interpolate to get whatever inter
>> sample values you need.
> 
> sounds like a great idea.
> 
> I should do that with the output too, but it's a little more complex
> there: In the beginning I've tried to take the average for all the
> "spice"-samples matching the corresponding audio-sample. I've only tried
> that up to 1/(4*Fsample) and it gave much worse results than just taking
> the closest sample...  - combining interpolation and resampling could be
> the solution.
> 
> now that I've got the framework, I'll dig into the details..

Since you're patching ngspice anyway, maybe introducing a fixed-timestep 
behavior into ngspice is easier? IMHO it's the 'correct' solution (cfr 
other mails).


Pieter




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