| 摘要 |
PURPOSE:To obtain a small coefficient value by using relatively large capacity by performing charge transfer by varying the ratio of input capacity and integral capacity according a filter coefficient supplied externally. CONSTITUTION:All terminals Ta, Tb1, Tb2, and Tn, and Tx1-Tx6 are grounded through switches S1-S4, and SW31-SW36. Then, the switch S4 is opened and the terminal Ta is connected to the side of a signal input terminal 1 through the switch S1; and some of terminals Tx1-Tx6 are grounded through the switches SW31-SW36 according to given filter coefficients, and the remainders are connected to the negative terminal 2 of an operational amplifier A. Further, the terminal Tb1 is connected to the side of the terminal 1 through the switch S2, and the terminal Tb2 is connected to the side of the terminal A of the amplifier through the switch S3. Thus, a signal input from the terminal 1 is smapled at certain repetitive timing in input capacitance constituted by the combination of capacities CA, CB and CX, and after weighting by a constant value, the resulting signal is transferred to a fixed capacitance C12 constituting integral capacity. |
