21. The method as claimed in claim 20 , wherein said ways include raising user's voice, changing to a quieter location, raising speech clarity, and giving up recognition process.
21. The method as claimed in claim 20 , wherein said ways include raising user's voice, changing to a quieter location, raising speech clarity, and giving up recognition process. 22. The method as claimed in claim 21 , wherein said user is prompted to raise the voice or change to a quieter location and re-input the signal when said SNR is lower than a threshold.