| 摘要 |
PURPOSE:To reduce errors in characteristics, generated during switching, as much as possible, by providing impedance networks whose characteristics are switched with an analog switch between a low and a high input impedance circuit. CONSTITUTION:Impedance circuits Z1 and Z2 are provided in series and in parallel between a buffer 1 with low input impedance and a buffer 2 with high input impedance. The impedance circuits Z1 and Z2 impose voltage division upon the output signal of the buffer 1 and the resulting signal is inputted to the buffer 2. For this purpose, using a prescribed circuit as the impedance circuit Z2 realize a spectral skewing circuit and an anticirculation circuit which are necessary for a noise reduction circuit. When an analog switch 4 for by-passing the impedance circuit Z1 is closed, the voltage division is not performed and another type of a noise reduction circuit is realized. |
