Title :
Linearity improvement of power amplifier using modulation of low frequency IMD signals
Author :
Jang, Mi Ae ; Kim, Sung Yong ; Jeon, Ki Kyung ; Kim, Young ; Jeong, Yong Chae
Author_Institution :
Sch. of Electron. Eng., Kumoh Nat. Inst. of Technol., Gyungbuk, South Korea
Abstract :
In this paper, a new predistortion linearizer for controlling the amplitude of low frequency intermodulation distortion signals is proposed. The low frequency intermodulation distortion (IMD) components are generated by harmonic generator. A vector modulator, modulate fundamental signal with low frequency IMD signals, generates predistortion IMD signals and controls amplitude and phase of them with modulation factors. As a result, this predistorter is suppressed IMD signals of power amplifier effectively. The predistortion linearizer has been manufactured to operate in cellular base-station transmitting band (869-894 MHz). The experimental results show that IMD3 of power amplifier are improved more than 20dB for CW two-tone signals. Also, it´s improved the adjacent channel power ratio (ACPR) more than 10dB for CDMA (IS-95) signals.
Keywords :
harmonic generation; intermodulation distortion; linearisation techniques; power amplifiers; 869 to 894 MHz; CDMA IS-95 signals; CW two-tone signals; adjacent channel power ratio; cellular base-station transmitting band; harmonic generator; intermodulation distortion; linearity improvement; low frequency IMD signals; power amplifier; predistortion IMD signals; predistortion linearizer; vector modulator; Amplitude modulation; Chirp modulation; Frequency modulation; Intermodulation distortion; Linearity; Manufacturing; Phase modulation; Power amplifiers; Predistortion; Signal generators; Linearization; intermodulation distortion; power amplifier; predistorter;
Conference_Titel :
Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings
Print_ISBN :
0-7803-9433-X
DOI :
10.1109/APMC.2005.1606482
