An apparatus for converting a continuous-time, continuously variable input signal into a sampled and quantized output signal, comprising: an input line for accepting the continuous-time, continuously variable input signal; and a processing branch (110, 120) coupled to the input line, said processing branch (110, 120) including: (a) a continuous-time quantization-noise-shaping circuit (113, 123); (b) a sampling/quantization circuit coupled to an output of the continuous-time quantization-noise-shaping circuit (113, 123); and (c) a digital bandpass filter (115, 125) coupled to an output of the sampling/quantization circuit; (d) a line coupling the output of the sampling/quantization circuit back into the continuous-time quantization-noise-shaping circuit (113, 123); said continuous-time quantization-noise-shaping circuit (113, 123) comprises an adder that includes a plurality of inputs and an output, with the continuous-time continuously variable 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 continuous time filter (154A, 154C) having a first transfer function, and the output of the sampling/quantization circuit being coupled to one of the inputs of the adder through a second continuous time filter (154B, 154C) having a second transfer function; the continuous-time quantization-noise-shaping circuit (113, 123) has a noise transfer function with a minimum at a particular frequency; wherein the minimum corresponds to a frequency band selected by the digital bandpass filter (115, 125); and each of the first transfer function and the second transfer function is at least one of a weighted sum or difference of two filter responses that have group delay and insertion gain that: (i) are approximately constant over the frequency band selected by the digital bandpass filter (115, 125), and (ii) approach zero at frequencies greater than those lying within a 20 dB bandwidth of the quantization-noise transfer function response as selected by the digital bandpass filter (115, 125). an input line for accepting the continuous-time, continuously variable input signal; and a processing branch (110, 120) coupled to the input line, said processing branch (110, 120) including: (a) a continuous-time quantization-noise-shaping circuit (113, 123); (b) a sampling/quantization circuit coupled to an output of the continuous-time quantization-noise-shaping circuit (113, 123); and (c) a digital bandpass filter (115, 125) coupled to an output of the sampling/quantization circuit; (d) a line coupling the output of the sampling/quantization circuit back into the continuous-time quantization-noise-shaping circuit (113, 123); (a) a continuous-time quantization-noise-shaping circuit (113, 123); (b) a sampling/quantization circuit coupled to an output of the continuous-time quantization-noise-shaping circuit (113, 123); and (c) a digital bandpass filter (115, 125) coupled to an output of the sampling/quantization circuit; (d) a line coupling the output of the sampling/quantization circuit back into the continuous-time quantization-noise-shaping circuit (113, 123); said continuous-time quantization-noise-shaping circuit (113, 123) comprises an adder that includes a plurality of inputs and an output, with the continuous-time continuously variable 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 continuous time filter (154A, 154C) having a first transfer function, and the output of the sampling/quantization circuit being coupled to one of the inputs of the adder through a second continuous time filter (154B, 154C) having a second transfer function; the continuous-time quantization-noise-shaping circuit (113, 123) has a noise transfer function with a minimum at a particular frequency; wherein the minimum corresponds to a frequency band selected by the digital bandpass filter (115, 125); and each of the first transfer function and the second transfer function is at least one of a weighted sum or difference of two filter responses that have group delay and insertion gain that: (i) are approximately constant over the frequency band selected by the digital bandpass filter (115, 125), and (ii) approach zero at frequencies greater than those lying within a 20 dB bandwidth of the quantization-noise transfer function response as selected by the digital bandpass filter (115, 125).