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:
Sep. 23, 2003
Filed:
Jun. 29, 2001
Sifen Luo, Hartsdale, NY (US);
Tirdad Sowlati, Ossining, NY (US);
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A bias circuit having a relatively long time constant improves the linearity of a radio frequency power amplifier of a spread spectrum mobile telephone by causing a power transistor of the amplifier to operate in class A or AB mode. The power amplifier thus derives an output signal that is a substantial replica of the spread spectrum input signal for all amplitudes of the input signal. The bias circuit has transistors connected in a feedback circuit which tends to oscillate to affect the amplifier operation. A low pass filter connected to the transistors suppresses the tendency. An interstage high pass matching circuit between a linear amplifier that drives the power amplifier includes a series capacitor and an inductor connected between an output terminal of the linear amplifier and a DC power supply terminal.