发明名称 |
Apparatus for detecting the presence or the absence of a digitally modulated carrier, a corresponding receiver, and a corresponding method |
摘要 |
The invention relates to apparatus for detecting the presence or the absence of a signal carrier wave received by a receiver. The carrier wave is modulated by a digital signal at a symbol clock frequency. According to the invention, the apparatus includes: a non-linear circuit receiving the received signal or the received signal after it has been frequency transposed, the non-linear circuit supplying in particular a signal whose frequency corresponds to the symbol clock frequency; a narrow-band filter centered on the symbol clock frequency and supplying a filtered signal; detection means for detecting the filtered signal and for supplying a detection signal; and comparator means for comparing the detection signal with a reference value, the output signal from the comparator means constituting a signal indicating the presence or the absence of the carrier wave. The invention is particularly applicable to a receiver including automatic gain control apparatus placed upstream, and the indicator signal may optionally be applied to automatic frequency control apparatus.
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申请公布号 |
US6081559(A) |
申请公布日期 |
2000.06.27 |
申请号 |
US19950565045 |
申请日期 |
1995.11.30 |
申请人 |
ALCATEL ESPACE |
发明人 |
LECLERC, GERARD;BLAVETTE, DENIS;LEMAITRE, DIDIER |
分类号 |
H04L1/20;(IPC1-7):H04L27/14;H04L27/16;H04L27/22 |
主分类号 |
H04L1/20 |
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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