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.
Patent No.:
Date of Patent:
Apr. 08, 2003
Filed:
Oct. 12, 2000
Scott Justice, Durham, NC (US);
Erik Bengtsson, Cary, NC (US);
Telefonaktiebolaget, LM Ericsson, Stockholm, SE;
Abstract
Differential voltage controlled oscillators are provided including a differential oscillator core, a first linear capacitor, a second linear capacitor, a first phase noise reduction device, and a second phase noise reduction device. The differential oscillator core has a first output that is capacitively coupled to a first differential input thereof by a first semiconductor junction having a first non-linear capacitance, and a second output that is capacitively coupled to a second differential input thereof by a second semiconductor junction having a second non-linear capacitance. The first linear capacitor is electrically cross-coupled from the first differential input to the second output, while the second linear capacitor electrically cross-coupled from the second differential input to the first output. The first phase noise reduction device has a first non-linear capacitance characteristic, and is electrically cross-coupled from the first differential input to the second output. The second phase noise reduction device has a second non-linear capacitance characteristic, and is electrically cross-coupled from the second differential input to the first output. By using the first and second phase noise reduction devices to add non-linear junction capacitance to each side of the differential structure, non-linear junction capacitances of the first and second semiconductor junctions are effectively canceled out to reduce the phase noise of the oscillators in which they are used.