User:Jscarisbrick/sandbox

The Dawson-Perreault Envelope Tracking method is an advanced form of Envelop Tracking Power Amplifier (PA) system for wideband cellular telephony in base-stations and handsets. Invented by two MIT professors Joel Dawson and David Perreault, it uses a digital power modulator to supply power to a CMOS or GaAs PA device instead of the analogue approach used by traditional Envelope Tracking (REFERENCE) methods. Digital Power modulators operate at very high efficiencies - but introduce significant adjacent channel noise. The Dawson-Perreault method reduces this by using adaptive Digital Signal Processing (DSP) to pre-distort the base-band signal to meet the stringent adjacent channel noise requirements of wideband communication systems.

At 5Mhz bandwidths the Dawson-Perreault Envelop Tracking can demonstrate XX% Power Added Efficiency in single PA handsets, and more in dual PA base-stations. Also, the Dawson-Perreault power modulator circuit works well at lower battery voltages than traditional Average Power or Envelop Tracking systems, extending battery life by allowing more energy to be extracted from a cellphone's battery as it discharges.

Driven by user requirements for high data rates to smart phones, cellular bandwidths are increasing from 20Mhz, to 40Mhz and beyond. Wifi bandwidths for IEEE 802.11ac can easily exceed 100Mhz. Traditional Envelop Tracking systems offer little or no efficiency advantage over Average Power techniques at bandwidths of 20MHz and beyond because of their analogue power modulation approach. By contrast, the Dawson-Perrealut ET Advanced method maintains it's high efficiency beyond 100Mhz.

Charts: ACLR

References: Wiki on ETA, Wiki on LTE, IEEE Conference Papers, US Patents., 18TW consumption...