Title :
A Polar Transmitter Using a Linear-Assisted Delta-Modulation Envelope-Amplifier for WCDMA Applications
Author :
Kunihiro, Kazuaki ; Takahashi, Kiyohiko ; Yamanouchi, Shingo ; Hirayama, Tomohisa ; Hida, Hikaru ; Tanaka, Shin-ichi
Author_Institution :
Syst. Devices Res. Labs., NEC Corp., Kanagawa
Abstract :
A polar transmitter using a new linear-assisted delta-modulation (LADM) envelope-amplifier has been developed for WCDMA applications. The LADM system is composed of a highly efficient switching block based on a 200-MHz-clock delta-modulator, which is implemented in a 0.18-mum CMOS IC, and a highly accurate linear block. In the LADM approach, the residual quantization noise and distortion of switching amplification are removed through the assistant linear process; thus, a sufficiently low ACPR of -45 dBc and a small EVM of 1.7% can be achieved without a pre-distortion technique. The developed polar transmitter nearly doubles the average efficiency in the 10- to 15-dB back-off region of class-AB PAs
Keywords :
CMOS integrated circuits; code division multiple access; delta modulation; microwave power amplifiers; radio access networks; transmitters; CDMA; CMOS; WCDMA applications; code division multiple access; envelope amplifier; linear assisted delta modulation; polar transmitter; power amplifiers; Bandwidth; Cutoff frequency; Delta modulation; Multiaccess communication; Peak to average power ratio; Pulse amplifiers; Pulse width modulation; Quantization; Transmitters; Wireless LAN; CMOS; Polar transmitter; code division multiple access (CDMA); delta modulation; power amplifiers;
Conference_Titel :
Microwave Conference, 2006. 36th European
Conference_Location :
Manchester
Print_ISBN :
2-9600551-6-0
DOI :
10.1109/EUMC.2006.281219
