PREDISTORTION CALIBRATION AND BUILT IN SELF TESTING OF A RADIO FREQUENCY POWER AMPLIFIER USING SUBHARMONIC MIXING
First Claim
1. A method of testing a radio frequency (RF) wireless transmitter, said method comprising the steps of:
- providing a frequency reference input;
providing a frequency synthesizer operative to generate an RF signal having a frequency in accordance with said frequency reference input;
providing a power amplifier (PA) operative to generate an RF output signal in proportion to an amplitude level;
coupling said RF output signal to said frequency reference input;
generating a phase error signal as a function of said frequency reference input and said RF signal; and
scanning through PA amplitude levels and analyzing the phase error signal generated thereby to detect defects in said power amplifier, wherein the phase error signal is a resultant phase error signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A novel and useful apparatus for and method of predistortion calibration and built-in self testing (BIST) of a nonlinear digitally-controlled radio frequency (RF) power amplifier (DPA) using subharmonic mixing. The RF power amplifier output is temporarily coupled into the frequency reference (FREF) input and the phase error samples generated in the phase locked loop (PLL) are then observed and analyzed. The digital predistortion and BIST mechanisms process the phase error samples to calibrate and test the DPA in the transmitter of the Digital RF Processor (DRP). The invention enables the characterization of nonlinearities, the configuration of internal predistortion, as well as the testing of the transmitter'"'"'s analog/RF circuitry, thereby eliminating commonly employed RF performance testing using high-cost test equipment and associated extended test times.
-
Citations
36 Claims
-
1. A method of testing a radio frequency (RF) wireless transmitter, said method comprising the steps of:
-
providing a frequency reference input; providing a frequency synthesizer operative to generate an RF signal having a frequency in accordance with said frequency reference input; providing a power amplifier (PA) operative to generate an RF output signal in proportion to an amplitude level; coupling said RF output signal to said frequency reference input; generating a phase error signal as a function of said frequency reference input and said RF signal; and scanning through PA amplitude levels and analyzing the phase error signal generated thereby to detect defects in said power amplifier, wherein the phase error signal is a resultant phase error signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method of predistortion calibration of a radio frequency (RF) power amplifier (PA) in a RF wireless transmitter, said method comprising the steps of:
-
providing a frequency reference input; providing a frequency synthesizer operative to generate an RF signal having a frequency in accordance with said frequency reference input; providing said power amplifier (PA) operative to generate a modulated RF output signal in proportion to an amplitude code; coupling said modulated RF output signal to said frequency reference input; generating a phase error signal as a function of said frequency reference input and the output of said frequency synthesizer; and applying an amplitude code to said PA and calibrating said PA for any amplitude and phase nonlinearities in accordance with the phase error signal generated thereby, wherein the phase error signal is a resultant phase error signal. - View Dependent Claims (17, 18, 19)
-
-
20. A radio frequency (RF) wireless transmitter, comprising:
-
a frequency reference input; a frequency synthesizer operative to generate an RF signal having a frequency in accordance with said frequency reference input; a digital power amplifier (DPA) operative to receive said RF signal and to generate a modulated RF output signal therefrom in proportion to an amplitude code; coupling means for coupling the output of said DPA to said frequency reference input; a phase detector operative to generate a phase error signal as a function of said frequency reference input and the output of said frequency synthesizer; and test means for scanning through DPA amplitude codes and analyzing the spectrum of a phase error signal generated thereby to detect defects in said transmitter, wherein the phase error signal is a resultant phase error signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
30. A single chip radio, comprising:
-
a polar transmitter, said transmitter comprising; a frequency reference input; a frequency synthesizer operative to generate an RF signal having a frequency in accordance with said frequency reference input; a digital power amplifier (DPA) operative to receive said RF signal and to generate a modulated RF output signal therefrom in proportion to an amplitude code; coupling means for coupling the output of said DPA to said frequency reference input; a phase detector operative to generate a phase error signal as a function of said frequency reference input and the output of said frequency synthesizer; test means for scanning through DPA amplitude codes and analyzing the spectrum of the phase error signal generated thereby to detect defects in said transmitter, wherein the phase error signal is a resultant phase error signal; a receiver; and a baseband processor. - View Dependent Claims (31, 32, 33)
-
-
34. A mobile communications device, comprising:
-
a cellular radio comprising a transmitter and receiver; said transmitter comprising; a frequency reference input; a frequency synthesizer operative to generate an RF signal having a frequency in accordance with said frequency reference input; a digital power amplifier (DPA) operative to receive said RF signal and to generate a modulated RF output signal therefrom in proportion to an amplitude code; coupling means for coupling the output of said DPA to said frequency reference input; a phase detector operative to generate a phase error signal as a function of said frequency reference input and the output of said frequency synthesizer; and a processor coupled to said transmitter and receiver, said processor operative to; scan through DPA amplitude codes and analyze the spectrum of the phase error signal generated thereby to detect defects in said radio, wherein the phase error signal is a resultant phase error signal. - View Dependent Claims (35, 36)
-
Specification