发明名称 |
PHASE CONTROLLED DEMODULATION SYSTEM FOR DIGITAL COMMUNICATION |
摘要 |
A carrier-to-noise detector comprises an A/D converter (1) which samples an output of the demodulator of a digital transmission system at a symbol clock rate and converting it to a digital signal having positive and negative values. An absolute value converting circuit (2) converts the output of A/D converter into an absolute value which is averaged by a first averaging circuit (3) over a period sufficient to suppress short term variations and then squared by a first squaring circuit (4) to give an output representing the carrier component. The output of A/D converter is, on the other hand, squared by a second squaring circuit (5) and averaged by a second averaging circuit (6) to suppress short term variations to give an output representing a total of the carrier and noise components. The carrier component in the output of the second averaging circuit 6 is subtracted by a subtractor (7). A ratio between the outputs of the first squaring circuit (4) and subtracting circuit (7) is derived by a divider (8) as a representation of a carrier-to-noise ratio. |
申请公布号 |
EP0497433(A3) |
申请公布日期 |
1992.09.23 |
申请号 |
EP19920201171 |
申请日期 |
1988.06.22 |
申请人 |
NEC CORPORATION |
发明人 |
YOSHIDA, SHOUSEI;OTANI, SUSUMU;TODOROKI, TOSHIYA |
分类号 |
G01R29/26;H04B17/00;H04L27/00;H04L27/227 |
主分类号 |
G01R29/26 |
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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