Title :
Optimization for error-canceling loop of the feedforward amplifier using a new system-level mathematical model
Author :
Yang, Youngoo ; Woo, Young Yun ; Kim, Bumman
Author_Institution :
Dept. of Electron. & Electr. Eng., Pohang Univ. of Sci. & Technol., South Korea
Abstract :
We present a system-level mathematical model to simulate the linearity of the feedforward amplifier. The model has fundamental and distortion signal sub-paths constructed from the data extracted by baseband system simulation. The calculated linearization performances using the model have been validated by comparison with the baseband system simulation results. From the calculated results, the optimum design of the error amplifier size and coupling factor of the output coupler for a down-link WCDMA signal with 16 data channels are provided to maximally achieve output linearity with a fixed power capacity of the amplifiers. Our data shows that the optimum size of the error amplifier is 0.45 times that of the main amplifier with the coupling factor of 5.5 dB.
Keywords :
circuit CAD; circuit optimisation; circuit simulation; code division multiple access; feedforward; linearisation techniques; radio equipment; radiofrequency amplifiers; ACLR; adjacent channel leakage ratio; baseband system simulation; data channels; distortion signal sub-paths; down-link WCDMA signal; error-canceling loop; feedforward amplifier; fixed power capacity; fundamental signal sub-paths; linearity; linearization performances; optimization; optimum error amplifier size design; output coupler coupling factor; output linearity; signal statistics; system-level mathematical model; Baseband; Distortion; Linearity; Mathematical model; Multiaccess communication; Peak to average power ratio; Power amplifiers; Radiofrequency amplifiers; Signal design; Statistics;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2002.807824
