发明名称 |
Systems, methods and computer program products for identifying digital impairments in modems based on clusters and/or skips in pulse code modulation signal levels |
摘要 |
Digital impairments in a set of Pulse Code Modulation (PCM) signal levels that are received at a client modem from a server modem are identified by compressing the set of PCM signal levels into a signature. Digital impairments are determined based on the signature. In a preferred embodiment, the PCM signal levels are compressed into a signature by identifying clusters and/or skips in the set of PCM signal levels. In particular, when transmitting PCM signal levels from a server modem to a client modem over a connection that is subject to digital impairments such as Robbed Bit Signaling (RBS) and/or PAD digital impairments and quantization, some adjacent PCM signal levels may become identical or very close to one another. Moreover, other adjacent signal levels may have a difference that is at least approximately twice the difference of other levels. The former phenomenon is referred to as a "cluster" and the latter phenomenon is referred to as a "skip". By identifying clusters and/or skips in the set of PCM signals that are received at the client modem from the server modem, a signature of the network connection may be obtained. Digital impairments including RBS and/or PAD may be identified using the signature.
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申请公布号 |
US6816545(B1) |
申请公布日期 |
2004.11.09 |
申请号 |
US19990430217 |
申请日期 |
1999.10.29 |
申请人 |
INTERNATIONAL BUSINESS MACHINES CORPORATION |
发明人 |
DAVIS GORDON TAYLOR;DHOLAKIA AJAY;HWANG DONGMING;WARE MALCOLM SCOTT;YE HUA |
分类号 |
H04L25/49;(IPC1-7):H04B1/38 |
主分类号 |
H04L25/49 |
代理机构 |
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主权项 |
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地址 |
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