Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Pipelining a recursive equation

Dear Forum, I am working on a polyphase filter implementation, which is built up from a number of recursive equations such as: A(n) = alpha*[X(n-1)-A(n-1)] + beta*[X(n)-A(n-2)] + X(n-2) ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Your refering to a case, where the filter time step equals a clock cycle and the arithmetic won't work without pipelining. Yes, you can't build an IIR filter in this situation.

However, looking at the above equation, only the term alpha*A(n-1) must be calculated in one filter time step. Reordering the equation may help.