A sigma-delta modulator (400) 400, 500, 600) for converting an input signal (X(s)) (X(s)) to a quantized output signal (Y(z)) (Y(z)), in which a feedback loop is provided between a filter (402) and a quantizer (403) of the modulator, the feedback loop configured to reduce quantization errors from the modulator by filtering and subtracting quantization noise fed back to an input of the quantizer (403).