| 摘要 |
PURPOSE:To give a number of degrees of freedom to the quantization error distribution for an analogue input voltage, by moving the transfer function for the analogue input voltage in parallel. CONSTITUTION:An analogue switch SW13 is closed, and movable terminals (a) of switches SW11 and SW15 are connected to fixed terminals (c) respectively, and movable terminals (a) of switches SW01-SW04, SW12, SW14, SW16, and SW17 are connected to fixed terminals (b). Then, a voltage VP at a point P is equal to 1/2VR1. Next, movable terminals (a) of switches SW14 and SW17 are moved to fixed terminals (c). Under this state, the movable terminal (a) of the switch SW12 is connected to the terminal (c). Then, the voltage VP is equal to 1/2VR1+1/2LSB, and this voltage is held in a capacitor C' through a voltage comparator 14. Next, the switch SW13 is opened, and switches SW01-SW04, SW11, SW12, and SW14-SW17 are connected to terminals (b), and the switch SW13 is closed, thus taking in an analogue input. The switch SW13 is opened, and movable terminals of switches SW11, SW16, and SW17 are connected to terminals (c). Then, a voltage VQ at a point Q is changed to 1/2VR1+1/2LSB and becomes a reference voltage of the voltage comparator hereafter. |
