Analog to digital conversion system

An analog to digital conversion system, comprising:

• a first chopper, responsive to a chop signal having a period T, for passing an analog signal to an output with non-reversed polarity during a first portion of the period T and with reversed polarity during a second portion of the period T;
• an analog to digital converter for producing a first set of at least one digital word corresponding to the analog signal with non-reversed polarity and an offset voltage and for producing a second set of at least one digital word corresponding to the analog signal with reversed polarity and the offset voltage;
• a second chopper, responsive to the chop signal, for passing to an output of the second chopper one of the produced first and second sets with non-reversed polarity, and passing to the output of the second chopper the other one of produced first and second sets with reversed polarity;
• and,
• a filter, fed by the output of the second chopper, for producing, on receipt of the produced first set, a first output digital word and, on receipt of the produced second set, a second output digital word, with the offset voltage being removed from each of such output digital words.

An analog to digital conversion system, comprising:

• a first section, for periodically producing a pair of signals during each period T, one of the signals in the pair being an analog signal, +A.sub.IN, and the other signal in the pair being an analog signal, -A.sub.IN ;
• signal conditioning circuitry, fed by the pair of signals +A.sub.IN and -A.sub.IN, for producing a corresponding pair of signals, +A'.sub.IN +V.sub.OSSC and -A'.sub.IN +V.sub.OSSC, where V.sub.OSSC is an offset voltage produced by the signal conditioning circuit;
• an analog to digital converter, fed by the pair of signals +A'.sub.IN +V.sub.OSSC and -A'.sub.IN +V.sub.OSSC, for producing corresponding digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›A'.sub.IN +V.sub.OS !.vertline..sub.DIG, where V.sub.OS is the total offset voltage of the signal conditioning circuit and the analog to digital converter;
• a second section, fed by the digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›-A'.sub.IN +V.sub.OS !.vertline..sub.DIG produced by the analog to digital converter, for producing corresponding digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›+A'.sub.IN -V.sub.OS !.vertline..sub.DIG ;
• an output filter fed by the digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›+A'.sub.IN -V.sub.OS !.vertline..sub.DIG produced by the second section, for removing therefrom V.sub.OS, and for producing at an output a digital word A".sub.IN .vertline..sub.DIG for the digital word ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and an output digital word A".sub.IN .vertline..sub.DIG for the digital word ›+A'.sub.IN -V.sub.OS !.vertline..sub.DIG.

An analog to digital conversion system, comprising:

• a pair of input terminals for providing an analog signal, A.sub.IN ;
• a first section, fed by the analog signal at the pair of terminals and a train of switching signals having successively alternating binary switching states with periodicity, T, such first section having a pair of output terminals, such first section coupling a first one of the pair of input terminals to a first one of the pair of output terminals and a second one of the pair of input terminals to a second one the output terminals in response to a first one of the binary switch states to produce a voltage +A.sub.IN between the output terminals and for coupling the first one of the pair of input terminals to the second one of the pair of output terminals and the second one of the pair of input terminals to the first one of the output terminals in response to a second one of the binary switch states to produce a voltage -A.sub.IN between the output terminals;
• signal conditioning circuit, fed by the pair of signals +A.sub.IN and -A.sub.IN, for producing a corresponding pair of signals, +A'.sub.IN +V.sub.OSSC and -A'.sub.IN +V.sub.OSSC, where V.sub.OSSC is an offset voltage produced by the signal conditioning circuit;
• an analog to digital converter, fed by the pair of signals +A'.sub.IN +V.sub.OSSC and -A'.sub.IN +V.sub.OSSC, for producing corresponding digital words ›+A'.sub.IN +V.sub.OS !.vertline.DIG and ›A'.sub.IN +V.sub.OS !.vertline.DIG, where V.sub.OS is the total offset voltage of the signal conditioning circuit and the analog to digital converter;
• a second section, fed by the digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›-A'.sub.IN +V.sub.OS !.vertline..sub.DIG and the train of switching signals for producing corresponding digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›+A'.sub.IN -V.sub.OS !.vertline..sub.DIG ;
• an output filter fed by the digital words ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and ›+A'.sub.IN -V.sub.OS !.vertline..sub.DIG produced by the second section, for removing therefrom V.sub.OS, and for producing at an output a digital word A".sub.IN .vertline..sub.DIG for the digital word ›+A'.sub.IN +V.sub.OS !.vertline..sub.DIG and an output digital word A".sub.IN .vertline..sub.DIG for the digital word ›+A'.sub.IN -V.sub.OS !.vertline..sub.DIG.