| 摘要 |
PURPOSE:To set freely the Q value by grounding a positive-phase-sequence output of a voltage-current converting circuit in three voltage-current converting circuits constituting the 2nd order active equalizer to common via a capacitor and connecting a capacitor between the input and output with the capacitance selected as an optimum value. CONSTITUTION:An input signal Vi is fed to a positive-phase-sequence input and an output signal is fed to an opposite phase input in the 1st and 2nd voltage-current converting circuits 10, 20. Further, the positive-phase-sequence output of the circuit 20 is fed to the positive-phase-sequence input and the output signal is fed to the opposite phase input in the 3rd voltage-current converting circuit 30. Then a capacitor C1 is connected between the input and output and the positive-phase-sequence output of the circuit 20 is grounded to common through a capacitor C2. Thus, since the mutual conductance gm of the circuit 20 is made independent of the gain flat characteristic of the equalizer and dependent on the Q value the mutual conductance is changed by a bias current supplied externally. Thus, the Q value of the equalizer is set optionally without changing the capacitance of the capacitor.
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