Design and Implementation of Envelope Amplifier and Power Amplifier for Envelope Tracking in Polar Transmitters
T.K. Abdul Qadir1, V.Venkateswarlu2
1Mr. T.K. Abdul Qadir, VLSI and Embedded System, VTU Extension Center, UTL Technologies Ltd, Bangalore, Karnataka, India.
2Dr. V. Venkateswarlu, VLSI and Embedded System, VTU Extension Center, UTL Technologies Ltd, Bangalore, Karnataka, India.
Manuscript received on September 30, 2013. | Revised Manuscript received on October 05, 2013. | Manuscript published on October 30, 2013. | PP: 229-235 | Volume-3, Issue-1, October 2013. | Retrieval Number: A2233103113/2013©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Envelope tracking is an amplitude modulation technique for a polar transmitter. The circuit for implementing envelope tracking technique consists of an envelope amplifier (EA) and a power amplifier (PA) whose design and implementation on Cadence Virtuoso platform is presented. The envelope amplifier amplifies the envelope signal by a gain of 2 and the power amplifier requiring a power added efficiency (PAE) of 55-60% and a peak to average ratio (PAR) of 4-6dB tracks the envelope of the transmit signal to ensure it operates linearly, i.e. the supply voltage rides above the amplitude modulated signal. The envelope and phase signals are generated from envelope and phase power supply sources available in Cadence Virtuoso. The overall system efficiency is determined by the product of the envelope amplifier efficiency and PAE of the RF power amplifier.
Keywords: Polar transmitter, Envelope tracking, Phase modulation, Amplitude modulation, Envelope amplifier and Power amplifier.