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:
Nov. 10, 1998
Filed:
Jul. 30, 1997
Paul Wilkinson Dent, Pittsboro, NC (US);
Ercisson Inc., Research Triangle Park, NC (US);
Abstract
A frequency synthesizer includes a controlled oscillator which is responsive to a frequency control input signal, to generate an output frequency. A programmable frequency divider is responsive to the output frequency and to a divider control input, to divide the output frequency by a first integral ratio or by a second integral ratio in response to the divider control input, to thereby produce a divided signal. A phase comparator is responsive to a reference frequency signal and to the divided signal, to compare the reference frequency signal and the divided signal, and thereby produce a first error signal. A sigma-delta modulator is responsive to a modulation input to produce the divider control input. A loop filter is responsive to the first error signal, to thereby produce the frequency control input signal. Ripple compensation signals and direct modulation signals may also be provided, to provide a three-point modulator for a frequency synthesizer. Analog and digital embodiments may also be provided.