Finite impulse response digital filter

A finite impulse response digital filter, comprising:

• a data multiplexer for routing a sample signal selected from an input sample signal and a feedback sample signal;
• a plurality of delay registers connected in series for latching sequential sample signals, said plurality of delay registers including a first register for generating said feedback sample signal and a second register for receiving said selected sample signal from said data multiplexer;
• a coefficient multiplexer for selecting one of a plurality of coefficients;
• a multiplier for generating a product of said selected sample signal and a selected coefficient;
• an adder for combining said product with previous products to obtain a sum of products;
• an accumulator register for latching said sum of products, wherein said adder receives said latched sum of products, said adder combining successive products with said latched sum of products to obtain successive sums of products;
• and
• a zero adjust generator for resetting said adder by generating a zero value signal, said zero adjust generator determining whether said adder receives said latched sum of products or said zero value signal.

A method of filtering data, comprising the steps of:

• sequentially latching successive samples to generate successive feedback samples for a desired cycle time;
• selecting between an input sample and said feedback samples prior to said latching step;
• multiplying each feedback sample with a selected coefficient to obtain a resulting product;
• adding said resulting product to a previous resulting product to obtain a sum of products;
• latching said sum of products to generate a filter output at completion of said desired cycle time;
• circulating said sum of products such that said adding step combines successive resulting products to said sum of products to obtain successive sum of products;
• and
• resetting said adding step at initiation of said desired cycle time by adding a zero value signal instead of a previous sum of products to a first resulting product.