发明名称 |
Digital method and apparatus for reducing EMI emissions in digitally-clocked systems |
摘要 |
A clock reference frequency is digitally derived from a base signal, then digitally modulated by ramping the clock reference frequency up and down about a desired frequency. The modulation occurs in periodic fashion at a prescribed modulation frequency. Such modulation spreads the electromagnetic energy of the system signals over a band that is a portion of the desired clock frequency. As a result, energy in harmonics of the respective system signals also are spread. When the energy spreading of any system signal or harmonic of such signal occurs over a bandwidth greater than the 120 kHz bandwidth of conventional communication receivers, adverse EMI emissions are reduced.
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申请公布号 |
US5909144(A) |
申请公布日期 |
1999.06.01 |
申请号 |
US19970978181 |
申请日期 |
1997.11.25 |
申请人 |
HEWLETT-PACKARD COMPANY |
发明人 |
PUCKETTE, ROBERT B. E.;BROWN, PRESTON D. |
分类号 |
H04L25/02;G06F1/04;G06F1/10;G06F7/62;G09G5/18;H03K5/156;H03K7/00;H03K23/66;H03L7/06;H04B1/68;(IPC1-7):H03D1/04 |
主分类号 |
H04L25/02 |
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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