David J 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.