| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for detecting a UW signal in which incorrect recognition of the UW signal is prevented when a received demodulation signal is is mixed with noise. <P>SOLUTION: The method for recognizing a UW signal included in a received signal comprises first to five steps of: (1) calculating the correlation value of the received signal and a well known UW signal on the receiving side; (2) testing whether the peak value of the correlation value exceeds a predetermined first threshold or not; (3) calculating a correlation value S from the peak value of the correlation value, calculating a correlation value N from the correlation value around the correlation value S, and calculating the S/N ratio from the correlation value S and the correlation value N if the results from test in the second step is yes; (4) testing whether the S/N ratio in the third step exceeds a predetermined second threshold; and (5) outputting an OK signal indicating recognition of the UW signal if the test result in the fourth step is yes. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
