Analog-to-digital converters

An oversampling converter of a type using a plural-order, plural-stage (10,20,30) sigma-delta modulator, the output signal to the decimating filter (50) of which modulator has the quantization noise contribution of a number of its plurality of stages suppressed therein, uses single-bit quantization (15,25) in those stages (10,20) to help avoid problems of nonlinearity. Each other sigma-delta converter stage (30), the quantization noise of which appears in substantial amount in the converter output signal to the decimating filter, uses quantization (35) having multiple-bit resolution to help increase the resolution of the oversampling converter overall.