Forum Discussion
Altera_Forum
Honored Contributor
12 years ago --- Quote Start --- Is it possible to use complex coefficients with the FIR Compiler II? If so, what notation is used to specify this when loading coefficients from a file into the wizard? I've tried i and j, but the wizard is complaining about invalid coefficients. --- Quote End --- I know dspbuilder doesn't support complex filter but you can use four real filters and do the complex addition/subtraction manually. remember for every tap the following multiplication is needed: yr = xr.hr - xi.hi yi = xr.hi + xi.hr thus the terms xr.hr becomes one filter for these inputs and the term xi.hi a second filter and so on. Finally you add/subtract the outputs of two pair filters to get real and imag output. You can alsouse three filters by some trick.