The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Oct. 01, 1996

Filed:

Dec. 09, 1993
Applicant:
Inventors:

Roger J Maitland, Woodlawn, CA;

Hal H Ireland, Kanata, CA;

Assignee:

Northern Telecom Limited, Montreal, CA;

Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
375371 ; 375373 ; 327152 ; 327153 ; 331 57 ; 370108 ; 3701053 ;
Abstract

A circuit for providing a phase controlled clock output includes a ring oscillator having a delay line for providing an internal clock signal whose period varies with on-chip variations due to temperature, voltage, and process. The circuit also includes a clock phase select circuit having a counter and divider for determining the number of delays in one external clock period and an input for a phase select value. A delay line having delay elements similar to those of the ring oscillator provides multiple delayed clock signals from the reference clock signal. A multiplexor having odd and even sides is used to select the desired clock signal in a glitchless manner. The phase controlled clock signal output is controlled by the phase select signal and is compensated for on-chip variations due to temperature, voltage, and process.


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