[hpsdr] WELCH_WINDOW in Kiss Konsole

[Kok Chen]

On Dec 28, 2016, at 5:43 AM, georg Prinz wrote:

> I never encountered the Dolph-Chebyshev window in a real application. Looking at the fourier transform, this should be an ideal function, isn`t it?

Dolph-Chebysev windows have equiripple for the prototype function.  After they are applied to weight a filter's input, the resultant filter is no longer equiripple.  I.e., the window itself is equiripple, the resultant filter is not.

To get an equiripple FIR filter, you will need to use something like the Remez Exchange algorithm to design the filter.  I do not know of a simple window that will result in an equiripple filter.

Dolph-Chebysev was quite popular in the analog days.  Once digital filters, specifically FIRs, became practical, they fell to disuse.  I had used Dolph-Chebysev even up to the late 1970s together with FIRs.

73 es Happy New Year

Chen, W7AY