FIR digital filters with sigma-delta modulated inputs and their implementation

Consideration is given to a finite impulse response (FIR) digital filter structure in which the input signal is encoded using sigma-delta modulation. This filter structure can be built using simple hardware, and it can accept analog signals directly without an additional analog-to-digital converter. The signal-to-noise ratio of this filter structure due to the encoding/decoding processes is derived. An efficient implementation of this filter is considered