Analogue-to-digital converter

摘要

An analogue-to-digital converter for converting the output of a switching mixer 401 in a radio receiver comprises two single-ended oversampled sigma-delta converters receiving alternate outputs from the mixer and providing outputs that are interleaved 406 to form an output bit stream. The converters respectively have positive and negative gains. The common-mode feedback circuit 410 prevents common-mode drift. Overload may be sensed by detecting that the frequency of the digital output signal has fallen below a threshold (figures 6-8).