Patent ID: 8089382

Claim:
An apparatus for converting a continuous-time, continuously variable signal into a sampled and quantized signal, comprising: an input line for accepting an input signal that is continuous in time and continuously variable; a plurality of processing branches coupled to the input line, each of said processing branches including: (a) a quantization-noise-shaping continuous-time filter, (b) a sampling/quantization circuit coupled to an output of the quantization noise-shaping continuous-time filter, (c) a digital bandpass filter coupled to an output of the sampling/quantization circuit, and (d) a line coupling the output of the sampling/quantization circuit back into the quantization-noise-shaping continuous-time filter; and an adder coupled to outputs of the plurality of processing branches, wherein each of said quantization-noise-shaping continuous-time filters comprises an adder that includes a plurality of inputs and an output, with the input signal being coupled to one of the inputs of the adder, the output of the adder being coupled to one of the inputs of the adder through a first filter, the output of the sampling/quantization circuit in the same processing branch being coupled to one of the inputs of the adder through a second filter, and the second filter having a different transfer function than the first filter, wherein the quantization-noise-shaping continuous-time filters in different ones of the plurality of processing branches have quantization noise minima at different frequencies, and wherein the quantization noise minimum for each of the quantization-noise-shaping continuous-time filters corresponds to a frequency band selected by the digital bandpass filter in the same processing branch.