| 摘要 |
PURPOSE:To simplify the circuit and to control electronically the characterstic by using a switching circuit controlled by a microcomputer and an R-2R ladder type resistance network for an attenuation section of a low and high frequency signal. CONSTITUTION:The input signal is fed respectively to an LPF 6, a BPF 7 and an HPF 8. The output of the LPF 6 and the HPF 8 is inputted to the next R-2R ladded type resistance network 10 from a switch element selected by a switching circuit 9 controlled by a microcomputer or the like respectively and the emphasized or attanuated output and the output of the BPF 8 are fed to an adder circuit 11. In applying respectively the weighting by K in the LPF 6 and the HPF 8, a resistor Rx is selected as a value attenuating the output of both the said filters by K.
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