| 摘要 |
PURPOSE: A method for canceling echoes in a mobile system is provided to maximize the efficiency and system tone quality of a DSP(Digital Signal Processor) by analyzing the performance required according to the DSP's operation mode for each channel under a multi-channel environment and utilizing a spare performance portion. CONSTITUTION: If an external interrupt is generated(ST11), an NLMS algorithm confirms whether the channel having the interrupt is allocated(ST12). In case that the channel is allocated, the NLMS algorithm determines an algorithm operation mode(ST13). If the algorithm operation mode is QCELP 8K, the NLMS algorithm sets NLMS to YES and TAP to 384(ST14) and activates the echo canceller(ST17). The echo canceller executes QCELP 8K vocoding(ST18). If the algorithm operation mode is QCELP 13K, the NLMS algorithm sets NLMS to YES and TAP to 256(ST15) and activates the echo canceller(ST17). The echo canceller executes QCELP 13K vocoding(ST19). In case that the algorithm operation mode is EVRC, the NLMS algorithm sets NLMS and TAP to NO and 256 respectively(ST16) and activates the echo canceller(ST17). The echo canceller executes EVRC vocoding(ST20).
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