| 摘要 |
A method and apparatus (20, 120) for analog-to-digital (A/D) converting an input signal having a first polarity include providing an integrator (22) including a capacitance (40) coupled to an input port of an amplifier (42), coupling an A/D converter (24) to an output port of the amplifier (42), changing the amount of charge stored in the capacitance (40) by coupling the input signal and a reference source (26, 28) having a second and opposite polarity to the capacitance (40), and controlling an A/D conversion cycle of the A/D converter (24) to simultaneously charge and discharge the capacitance (40) with the input signal and the reference source (26, 28) prior to each A/D conversion cycle. Another method and apparatus (20, 120) for analog-to-digital (A/D) converting an input signal include providing an integrator (22) including a capacitance (40) coupled to an input port of an amplifier (42), coupling an A/D converter (24) to an output port of the amplifier (42), changing the amount of charge stored in the capacitance (40) at a known time rate by alternately coupling the input signal and a reference source (26, 28) to the capacitance (40) through at least one switch (30, 32, 34, 132, 134, 158, 160), and controlling an A/D conversion cycle of the A/D converter (24) and the at least one switch (30, 32, 34, 132, 134, 158, 160) for controlling the coupling of the input signal and the reference source (26, 28) to the capacitance (40).
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