Honored ContributorI use dspbuilder to design a FIR ,the parameter is input 8bit，output 8bit ,fs 10M ,fc 1M,order16 Direct FIR.
However the problem is genrated: first,the filter coefficents can not convert to interger;Second,when use the Filter design&analysis tool to convert to interge ,the quantization error is too big to ignore. What can I do ?
Honored ContributorDesign a bigger filter?
Honored ContributorYou mean that I should increse the filter order,but we kown that the order is still limited in
improving the performence of the filter.Honored ContributorI'm not using DSPBuilder and don't know, what "can not convert to integer" means in this regard. I assume, that some kind of coefficient scaling is performed by any FIR design tool. If I use the Quartus FIR compiler, it would also have issues to realize a certain filter characteristics with insufficient coefficient length. You didn't actually tell the used coefficient length or internal data length, just I/O data length of 8 bit.
design a bigger filter could be also understood as increasing data and coefficient length, which seems to be necessary in this case. But you have to know your specification, how far 8-bit data length is meaningful for your application and about the intended filter characteristics.
