[sdiy] Do digital filters still explode?

[Eric Brombaugh]

All due respect to Colin, but that's a pretty broad statement. I'd imagine that the stability of a filter under any operating conditions, including audio rate modulation depends to a high degree on the filter architecture as well as how one is modulating it.

I've seen some discussion of filter modulation in the past that revolved around different ways of interpolating between sets of filter coefficients. If the interpolated pole trajectories veer outside the unit circle of the z plane then you'll surely see instability. Designing interpolation techniques that avoid this is a topic that generates a lot of research papers.

Eric

On Feb 5, 2011, at 8:44 PM, karl dalen wrote:

> I think it was Collin Fraser who some years ago mentioned that
> digital filters explode if they are audio rate modulated, have
> that been solved now or do they still explode?
> 
> I recall that to some discussions on DSP list that had a thread
> subject something like: What else are there left to emulate? 
> 
> Reg
> Kd
> 
> 
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