Ronald O Oliver

Author:

Ronald Oliver

ISBN #:

0533102219

US Patent:

6393262, May 21, 2002

Filed:

Jan 11, 2000

Appl. No.:

09/480960

Inventors:

Teresa Anne Muhlbauer - Cary NC
Ronald Oliver - Cary NC

Assignee:

Ericsson Inc. - Reseach Triangle Park NC

International Classification:

H01Q 1112

US Classification:

455127, 455107, 333124, 333 173

Abstract:

Difference frequency impedance transformation circuits for power amplifiers can change the impedance presented to an input of a power amplifier at a frequency that is a function of a difference between the receive and transmit frequency ranges. The difference frequency impedance transformation circuit may, therefore, reduce the noise at the difference frequency which may otherwise be mixed with the transmit frequencies to produce noise in the receive frequency range. In particular, difference frequency impedance transformation circuits can include a first circuit that conducts the first signals to an input of the power amplifier. A second circuit is electrically coupled to the input of the power amplifier and changes the impedance presented to the input of the power amplifier at the difference frequency. Related power amplifier systems, wireless user terminals, and methods are also disclosed.