Patent ID: 8275341

Claim:
A fixed point finite impulse response (FIR) filter comprising: a filter input stage configured to receive an input signal as a sequence of input samples and to generate an intermediate signal comprising a sequence of filtered samples, wherein the filtered samples have a larger number of bits than the input samples; and an output stage configured to truncate k least significant bits from each of the filtered samples to generate a sequence of output samples, wherein the output stage is configured to perform adaptive truncation where a value of k is modified in order to truncate a variable number of least significant bits from the filtered samples during operation of the fixed point FIR filter; wherein the output stage comprises: a feedback controller configured to determine a power of each output sample and, in response to the determination, adjust the value of k; and a variable truncation unit configured to truncate the k least significant bits from each of the filtered samples to thereby generate a sequence of truncated samples.