# Nyquist (Nth) digital filters

I am working in something were I should use a upsampling filter. I have decided to use a Nyquist filter(Lth filter). I know that there are two constraints. The first The frequency vector values must mirror each other in pairs around $\pi/2$. The second is the amplitude vector values must mirror each other in pairs around a magnitude of 0.50 What I am looking for are references to actually design these types of filters. I cant find any references that show how to implement them.

So dose anyone have a decent reference on hoe to design these filters? Does anyone have a reference on implementing these in Verilog?

## 1 Answer

This Mathworks documentation gives a good overview about the different parameters: http://uk.mathworks.com/help/dsp/examples/fir-nyquist-l-th-band-filter-design.html?requestedDomain=uk.mathworks.com

This tutorial goes into more detail: http://www.analog.com/media/en/training-seminars/tutorials/MT-002.pdf

And this one may be useful to clarify any doubt in the concepts presented before: http://www.lumerink.com/courses/ECE697A/docs/Matlab%20Filter%20Design%20and%20Implementation.pdf

hope this helps

• Perfect. I was looking for something like the second article. For what ever reason I could not find it but I knew something like it existed. Thanks. – bob Mar 12 '16 at 16:30