David C Coons

US Patent:

7457586, Nov 25, 2008

Filed:

Jun 13, 2005

Appl. No.:

11/151023

Inventors:

Alexander Wayne Hietala - Phoenix AZ, US
Adam Walter Toner - Kernersville NC, US
David Durgin Coons - Greensboro NC, US

Assignee:

RF Micro Devices, Inc. - Greensboro NC

International Classification:

H04B 1/00
H04B 15/00

US Classification:

455 631, 455 73, 4551143, 375296

Abstract:

A method is provided for calibrating Amplitude Modulation to Phase Modulation (AM/PM) predistortion coefficients for a polynomial used to compensate for AM/PM distortion of a power amplifier in the transmit chain of a mobile terminal. In general, the power amplifier is controlled by a variable supply voltage, which is generated based on an adjustable power control signal. After the power amplifier is placed in the mobile terminal, a predetermined data pattern is transmitted in a transmit burst. During the transmit burst, the variable supply voltage is changed from a first value to a second value, and a resultant phase shift in the radio frequency output signal provided by the mobile terminal is measured. Based on the phase shift, one of numerous predetermined sets of AM/PM predistortion coefficients is selected as the AM/PM coefficients for the mobile terminal.

US Patent:

7545880, Jun 9, 2009

Filed:

Aug 29, 2007

Appl. No.:

11/847044

Inventors:

David Coons - Greensboro NC, US
Brian Baxter - High Point NC, US

Assignee:

RF Micro Devices, Inc. - Greensboro NC

International Classification:

H04K 1/02

US Classification:

375296, 375297, 330149

Abstract:

A system is provided for pre-distorting a transmit signal in a mobile terminal prior to amplification by a power amplifier to compensate for AM to AM and AM to PM distortion over an input value range. Pre-distortion circuitry includes both amplitude and phase pre-distortion circuitries. The amplitude pre-distortion circuitry distorts an amplitude component of a polar transmit signal using an amplitude compensation signal that essentially cancels the AM to AM distortion, and the phase pre-distortion circuitry distorts a phase component of the polar transmit signal using a phase compensation signal that essentially cancels the AM to PM distortion. The amplitude and phase compensation signals are generated based on corresponding sets of coefficients selected from a number of sets of coefficients defining polynomials describing compensation signals for each of at least two subsets of the input value range for each of two or more power levels of the power amplifier circuitry.

US Patent:

7551686, Jun 23, 2009

Filed:

Jun 23, 2004

Appl. No.:

10/874509

Inventors:

David Coons - Greensboro NC, US
Brian Baxter - High Point NC, US

Assignee:

RF Micro Devices, Inc. - Greensboro NC

International Classification:

H04K 1/02

US Classification:

375296, 4551143, 330149

Abstract:

A system is provided for pre-distorting a transmit signal in a mobile terminal prior to amplification by a power amplifier to compensate for AM to AM and AM to PM distortion over an input value range. Pre-distortion circuitry includes both amplitude and phase pre-distortion circuitries. The amplitude pre-distortion circuitry distorts an amplitude component of a polar transmit signal using an amplitude compensation signal that essentially cancels the AM to AM distortion, and the phase pre-distortion circuitry distorts a phase component of the polar transmit signal using a phase compensation signal that essentially cancels the AM to PM distortion. The amplitude and phase compensation signals are generated based on corresponding sets of coefficients selected from a number of sets of coefficients defining polynomials describing compensation signals for each of at least two subsets of the input value range for each of two or more power levels of the power amplifier circuitry.

US Patent:

7864491, Jan 4, 2011

Filed:

Aug 28, 2007

Appl. No.:

11/846237

Inventors:

Ruediger Bauder - Feldkirchen-Westerham, DE
David Durgin Coons - Greensboro NC, US
David C. Dening - Stokesdale NC, US
Jon D. Jorgenson - Greensboro NC, US

Assignee:

RF Micro Devices, Inc. - Greensboro NC

International Classification:

H01H 9/30
H01H 73/18

US Classification:

361 13, 361 2, 361 8

Abstract:

Pilot switch circuitry coupled across first and second terminals of a microelectromechanical system (MEMS) switch is provided to reduce or eliminate arcing between a cantilever contact and a terminal contact when the MEMS switch is opened or closed. The pilot switch circuitry establishes a common potential at the first and second terminals prior to, and preferably until, the cantilever contact and terminal contact come into contact with one another when the MEMS switch is closed. The pilot switch circuitry may also establish a common potential at the first and second terminals prior to, and preferably after, the cantilever contact and terminal contact separate from one another when the MEMS switch is opened.