Edwin W Rowand

US Patent:

20020180498, Dec 5, 2002

Filed:

Mar 1, 2002

Appl. No.:

10/087521

Inventors:

William O'Leary - Plano TX, US
Edwin Rowand - Dallas TX, US

International Classification:

H03L007/06
H03L007/00

US Classification:

327/156000, 327/143000

Abstract:

Phase locked loops adapted to filter and store data indicative of the control signal applied to an oscillator permit suppression of tracking in the event of a step change in the phase difference between the reference clock signal and the feedback signal in the phase locked loop. Such phase locked loops further facilitate compensation for drift of the oscillator. Such phase locked loops are suitable for use in timing circuits of communications systems.

US Patent:

53770927, Dec 27, 1994

Filed:

Nov 16, 1992

Appl. No.:

7/977018

Inventors:

Edwin W. Rowand - Richardson TX
Donald J. Lucas - Richardson TX

Assignee:

International Power Machines - Garland TX

International Classification:

H02M 112

US Classification:

363 41

Abstract:

There is described a method and apparatus for substantially cancelling harmonic distortion from the output voltage signal of a power supply. The system samples the output of the power supply and detects the harmonic distortion within the output signal. After the harmonic distortion is detected, the amplitude of the real and imaginary components of the harmonic distortion are determined. The amplitude components are applied to a PI compensator to generate the harmonic distortion correction signal necessary to substantially cancel harmonic distortion from the output voltage signal. The harmonic distortion correction signal is then applied to the power supply.