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:
Feb. 03, 1998
Filed:
Feb. 28, 1995
Xue-Song Zhou, Chapel Hill, NC (US);
Ericsson Inc., Research Triangle Park, NC (US);
Abstract
A high power, low noise voltage-controlled oscillator (VCO) eliminates the drive-stage amplifier and costly surface-acoustic wave (SAW) inter-stage filter in a transmitter such as a cellular radiotelephone. The VCO includes a resonant circuit, an active part connected to the resonant circuit, and a buffer amplifier, connected to the active part, for isolating the VCO from a load connected to the buffer amplifier. The active part includes at least one transistor in a Colpitts configuration; capacitances connected in parallel with junction capacitances of the transistor, each capacitance having a value that is greater than a value of the respective junction capacitance with which it is connected in parallel; and a resistance for providing negative feedback at low frequencies. A second resistance may be provided for reducing the gain of the active part when oscillation starts. The buffer amplifier is a linear amplifier including a transistor, and the active part and the buffer amplifier may be connected by a capacitance for reducing coupling between the active part and the buffer amplifier.