发明名称 |
TONE DETECTION WITH ALIASING BANDPASS FILTERS |
摘要 |
To detect a dual tone pair signal in a telephone communication system, the signal is sampled at the Nyquist frequency. The sampled signal is filtered to determine the top three tone frequency power results. The input signal is then resampled at one-half of the Nyquist frequency. The resampled signal is filtered to determine signal power in the row and column frequency bands. The top three power results from tone filtering and aliasing row and column bandpass filter power results are checked for lack of excess power to reject false digits.
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申请公布号 |
CA2293280(A1) |
申请公布日期 |
1998.12.17 |
申请号 |
CA19982293280 |
申请日期 |
1998.06.03 |
申请人 |
NORTEL NETWORKS CORPORATION |
发明人 |
SRINIVASAN, BALAJI |
分类号 |
H04Q1/457;(IPC1-7):H04Q1/457 |
主分类号 |
H04Q1/457 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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