Patent ID: 7075468

Claim:
A sigma-delta analog-to-digital converter for converting band-limited analog signals into corresponding digital signals, said analog-to-digital converter comprising: a loop sampling and quantization analog-to-digital converter including an input port, and an output port at which output digital signals are generated in response to resonated difference signals applied to said input port; a loop digital-to-analog converter including an input port coupled to said output port of said loop analog-to-digital converter, for generating an analog reconstruction of said output digital signals; an input summing arrangement including an input port coupled for receiving said band-limited analog signal and an output port coupled to said input port of said loop sampling and quantization analog-to-digital converter, for summing said band-limited analog signals with said analog reconstruction of said output digital signals and with filtered signals, to form said resonated difference signals, said loop sampling and quantization analog-to-digital converter, said loop digital-to-analog converter, and said input summing arrangement being coupled in a first loop having a first delay; and an analog filter including a single input port coupled to receive said resonated difference signals, and also including an output port at which said filtered signals are generated, which output port of said analog filter is coupled to said input summing arrangement to form a second loop including said analog filter and said input summing arrangement, which second loop is regenerative and has order greater than one, where order is the number of weighted transversal delays.