[PD] convolution weirdness

[Charles Henry]

forgot the patch...whoops

On 11/5/06, Charles Henry <czhenry at gmail.com> wrote:
> Hi, list,
>   I have practically abandoned the idea of making a subband adaptive
> filter scheme using externals, but have not given up on making a
> Newton-method, rather than a gradient descent method (Fourier
> deconvolution is a Newton method, for instance, LMS and NLMS is a
> gradient descent method).
>
> So, I've written the convolution routine and it works mostly.  There
> is a high frequency component of the error that doesn't make sense to
> me.  All I did was the complex multiplication of two fft's, and it
> seems like it's not handling the Nyquist frequency well.  Any ideas?
>
> Also, I wondered if there would be a way to move a block of samples
> (in this patch length 2*L) within a block of samples length 2*N, from
> the end of the block to the beginning of the block.  This would reduce
> latency of the filter patch (currently 2*N-L) to L (samples).  N is
> the filter length, and L is the intended latency.
>
> I've attached the patch, as is, where you can see the high-freq.
> weirdness that goes on.  Just turn on the filter using the toggle box
> above [s f_on$0] and hit the message [256 64], in that order.
>
> Any suggestions would be gratefully recieved!
> Chuck
>
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