| 摘要 |
A telephone set has a receiver for transducing a reception signal into a voice, a microphone for transducing a voice into a transmission signal and a comparing device. The comparing device compares the reception signal and the transmission signal, and a predetermined frequency pass band is in turn alternated according to a period of a first clock input to pass the reception signal and the transmission signal. The comparing device outputs a frequency pass band where the reception signal and transmission signal have a substantially equal and maximum level and a comparison result signal when the reception signal and transmission signal have the substantially equal level. The telephone set also includes a frequency indicator which generates a second clock with a period corresponding to the frequency pass band value signal as well as supplying the first clock to the comparing device, and a transmission signal controller which transmits the transmission signal to a transmission line, and a frequency band to be eliminated from the transmission signal is variably set on the basis of the second clock./! |
