1. An encoder comprising: a digital-to-analog converter having a plurality of inputs and an output; an integrator having an input and an output, the output of the digital-to-analog converter being connected to the input of the integrator; a quantizer having an input and an output, the output of the integrator being connected to the input of the quantizer; and the output of the quantizer being connected to at least one of the plurality of inputs of the digital-to-analog converter.