| 摘要 |
An echo cancel circuit is provided to solve a problem that echo is generated at a band beyond a particular frequency because an analog signal transmitted from the other party cannot be effectively canceled out at an entire frequency band required for voice transmission/reception for a mobile phone. In a cancel circuit, first and second analog signals are inputted to the first input terminal, the third analog signal which is generated according to the first analog signal and prevents the first analog signal from being outputted together with the second analog signal is inputted to the second input terminal, and the first analog signal among the first and second analog signals is canceled by the third analog signal and outputted. A resistor(23) is installed between an earphone microphone(10) and the first input terminal. The resistors(24,25) are installed at the second input terminal. The resistor(24) corresponds to the first load circuit and the resistor(25) corresponds to impedance of the earphone microphone(10).
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