| 摘要 |
A data transmitter-receiver device transmits a forward data to a communication channel, and receives a backward data with a returning echo noise from the communication channel. The device is provided with a first modulator for modulating the forward data into a first digital signal. A D/A converter converts the modulated first digital signal into a corresponding outgoing analog signal which is transmitted to the communication channel. A delay memory is operated to delay the forward data by a certain time delay corresponding to a return time interval of an echo noise. A second modulator modulates the delayed forward data into a second digital signal. An A/D converter receives an incoming analog signal to convert the same into a corresponding third digital signal. An echo canceler operates based on the first and second digital signals for removing an echo noise from the third digital signal. A demodulator demodulates the third digital signal after removal of the echo noise to produce a backward data.
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