Title :
Digital controlled adaptive feedforward amplifier for IMT-2000 band
Author :
Youngoo Yang ; Youngsik Kim ; Jeahyok Yi ; Joongjin Nam ; Bumman Kim ; Wonwoo Kang ; Shinwook Kim
Author_Institution :
Dept. of Electron. & Electr. Eng., Pohang Univ. of Sci. & Technol., South Korea
Abstract :
We present a broadband adaptive control method for IMT-2000 band multi-carrier power amplifiers adopting feedforward linearization. We have analyzed and implemented an error cancellation detection method employing a frequency hopping pilot and IF synchronous sampling correlator with DSP controller. An adaptive delta-modulated power gradient algorithm is used to adjust the signal and error cancellation loop control parameters. A 2.15 GHz feedforward power amplifier with digital controller is implemented. Band test results show that it covers over a 90 MHz band with more than 50 dBc of IMD at 5 MHz offset frequency for an 8.3 MHz WCDMA signal. The adaptation result shows very fast convergence.
Keywords :
UHF circuits; UHF power amplifiers; code division multiple access; delta modulation; feedforward; frequency hop communication; intermodulation distortion; wideband amplifiers; 2.15 GHz; 8.3 MHz; 90 MHz; DSP controller; IF synchronous sampling correlator; IMD; IMT-2000 band; WCDMA signal; adaptive delta-modulated power gradient algorithm; broadband adaptive control method; digital controlled adaptive feedforward amplifier; error cancellation detection method; error cancellation loop control; feedforward linearization; feedforward power amplifier; frequency hopping pilot; multi-carrier power amplifiers; Adaptive control; Broadband amplifiers; Correlators; Digital control; Digital signal processing; Error correction; Frequency; Power amplifiers; Programmable control; Sampling methods;
Conference_Titel :
Microwave Symposium Digest. 2000 IEEE MTT-S International
Conference_Location :
Boston, MA, USA
Print_ISBN :
0-7803-5687-X
DOI :
10.1109/MWSYM.2000.862256
