Title :
Distortion mechanisms in supply modulation of polar transmitters
Author :
Alon, M. ; Singer, S. ; Spiegel, S.J.
Author_Institution :
Sch. of Eng., Tel Aviv Univ., Tel Aviv, Israel
Abstract :
The distortion mechanisms in supply modulation introduced by the PWM generator, the frequency response of DC regulator and the limited bandwidth of the high frequency recovery unit are analyzed for EDGE polar transmitters. It is demonstrated that there is an optimum regulator bandwidth that minimizes the total residual energy originated from the PWM generator and the low pass filter characteristics of the buck converter. The output spectrum was analyzed for a 5 MHz PWM clock frequency buck converter. The results show that in order to meet EDGE transmission mask requirements, the bandwidth requirements of the high frequency recovery unit should be at least 10 MHz for 300 KHz converter bandwidth while a 95 KHz converter bandwidth demands for no compensation at high frequencies.
Keywords :
PWM power convertors; distortion; mobile radio; radio transmitters; spectral analysis; telecommunication power supplies; DC regulator frequency response; EDGE polar transmitter supply modulation; EDGE transmission mask requirements; PWM clock frequency buck converter bandwidth; PWM generator; bandwidth 300 kHz; bandwidth 95 kHz; buck converter low pass filter characteristic; distortion mechanism; frequency 5 MHz; frequency recovery unit; optimum regulator bandwidth; residual energy minimization; spectrum analysis; Bandwidth; Buck converters; Character generation; DC generators; Frequency conversion; Frequency response; Pulse width modulation; Pulse width modulation converters; Regulators; Transmitters; PAE; Supply modulation; buck converters; polar transmitters; power amplifier; power control; wireless communication;
Conference_Titel :
Microwaves, Communications, Antennas and Electronics Systems, 2009. COMCAS 2009. IEEE International Conference on
Conference_Location :
Tel Aviv
Print_ISBN :
978-1-4244-3985-0
DOI :
10.1109/COMCAS.2009.5386083
