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:
Aug. 28, 1990
Filed:
Apr. 28, 1989
James S Irwin, Bastrop, TX (US);
Wayne P Shepherd, Sunrise, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A frequency synthesizer for providing a modulated output signal includes a phase comparator, a loop filter, and a voltage controlled oscillator (VCO). The phase comparator receives a reference input signal and a signal related to the VCO output, and generates a control current. A modulation circuit receives a modulation signal and provides both a modulation current and a modulation voltage. The modulation current is summed with the control current at one input of the loop filter, while the modulation voltage is applied to a second input of the loop filter. The VCO is controlled by the output of the loop filter to produce the modulated output signal.