| 摘要 |
PURPOSE:To obtain a filter circuit with ease of manufacture and the less number of components by constituting the filter circuit by a couple of input terminals receiving respectively signals with different phase, 1st and 2nd impedance circuits each comprising a capacitor and a coil and a 3rd impedance circuit comprising a resistor. CONSTITUTION:Signals different in phase by 180 deg. are supplied to a couple of input terminals 10A, 10B. The input terminal 10A is connected to an output terminal 20A via the impedance circuit 1 and the input terminal 10B is connected to the output terminal 20A via the impedance circuit 2. Moreover, the output terminal 20A is connected to ground via an impedance circuit 3. The filter circuit 30 is a 3rd-order filter circuit. Since the mutual inductance by a coil is not required in the filter circuit 30, the manufacture is facilitated. Moreover, a component for the connection is not required and the number of components is decreased. Then the filter is suitable as an all pass filter.
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