Many digital systems use filters to remove noise, provide spectral shaping, or perform signal detection. Two types of common filters that provide these functions are Infinite Impulse Response (IIR) and Finite Impulse Response (FIR) filters. IIR filters are used in systems that can tolerate phase distortion. FIR filters have an inherently stable structure, and are used in systems that require linear phase. This benefit makes FIR filters attractive enough that they are designed into a large number of systems. However, for a given frequency response specification, FIR filters are of higher order than IIR, making them computationally expensive.
The Lattice Serial FIR filter uses serial arithmetic elements to achieve a compact size. Due to the serial nature of the arithmetic, the data rate is slower than the clock rate and dependant on the data width. The effective throughput is defined as:
Data rate = (f/(ofw +1)
where ofw is the Output Full Width and f is the clock frequency.