0163313-A2 is referenced by 37 patents and cites 2 patents.

Method and apparatus are disclosed for dispersing the electromagnetic energy radiated from a digital system to minimize the EMI snd RFI emanating from such a system. To accomplish this, one approach of the present invention includes a VCO which is modulated by a band-limited signal to provide a system clock signal which has a broader spectral signature than the traditional precise crystal controlled oscillator traditionally utilized in digital systems. In addition, an optional feedback stage is disclosed for compensating for frequency drift of the VCO with time. This includes a precision crystal controlled oscillator operating at substantially the same frequency as the unmodulated VCO.; This signal is then continuously compared with the modulated output signal of the VCO to generate a compensation signal which in turn is combined with the modulation signal to minimize the long-term errors and thus minimize the long-term drift of the modulated clock signal. Another approach disclosed is to modulate the amplitude of the bus voltage being provided for the digital system.

Title
Method and apparatus for spectral dispersion of the radiated energy from a digital system.
Application Number
EP19850106696 19850530
Publication Number
0163313 (A2)
Application Date
May 30, 1985
Publication Date
December 4, 1985
Inventor
Crall Richard F
US
Assignee
Tektronix
US
IPC
H04B 15/02
H03L 07/18
H03B 29/00
H04B 15/02
H03L 07/06
H03B 29/00
H03K 03/00
H04B 15/04
H03L 07/06
H03B 29/00
H03K 03/84
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