| 摘要 |
PURPOSE:To obtain a filter for general use by controlling the connection between two low pass and high pass switched capacitor filters both of which controls cut-off frequency in accordance with clock frequency. CONSTITUTION:Frequency dividers 5, 6 are connected to a low pass switched capacitor filter 1 and a high pass switched capacitor filter 2 respectively. Receiving a clock signal from a terminal clock, the frequency dividers 5, 6 changes the frequency of the clock signal in accordance with dividing ratio variable signals from terminals C1-C4 and apply the frequency-converted clock signals to the filters 1, 2 respectively. The filters 1, 2 are used independently or connected in series or parallel to obtain required filter characteristics. Since each filter can change cut-off frequency in accordance with the frequency of the clock signal, a filter having optional characteristics can be obtained. |
