Design Con 2015
Breaking News
Comments
Newest First | Oldest First | Threaded View
JeremyHendy
User Rank
Rookie
re: Understand and characterize envelope-tracking power amplifiers
JeremyHendy   1/16/2012 2:26:02 PM
NO RATINGS
Almost all ET PAs are used in Class AB mode. And while the AM:PM distortion can't directly be controlled by the supply voltage, our experience with the vast majority of handset PAs is that correcting the AM:AM using IsoGain ET also brings the phase response into line. And simple memoryless correction of AM:PM ("DPD-Lite") is an increasingly common capability of the latest handset chipsets.

WKetel
User Rank
Rookie
re: Understand and characterize envelope-tracking power amplifiers
WKetel   1/12/2012 3:09:06 PM
NO RATINGS
I agree that an envelope-tracking amplifier does not have to be a "class C" amplifier, although that would provide the greatest efficiency, it could easily cause some distortion. The other comment is certainly valid, which is that it takes a great deal more effort to design an amplifier that will deliver a satisfactory level of distortion at various operating voltages. Phase modulation certainly does happen and it must be compensated for in order for the distortion level to be acceptable, and designing the correct compensation will certainly add a lot to the design effort.

XRF
User Rank
Rookie
re: Understand and characterize envelope-tracking power amplifiers
XRF   1/10/2012 5:28:31 PM
NO RATINGS
The surface response of an ET PA is more complex than a simple 3D RF-input vs battery-supply. Phase pushing and pulling will occur in such a 3D ET control solution. One comment on the transistion region to be noted; it is the same break-point as system modulation pre-distortion uses. There are two other break-points needed to arrive at the most effective ET modulation efficiency which are not mentioned in the text.

psi123
User Rank
Rookie
re: Understand and characterize envelope-tracking power amplifiers
psi123   1/5/2012 7:29:50 PM
NO RATINGS
The objection of the envelope tracking transmitters is to improve efficiency of the output signal. It is collecting the input signal data and replaces it with something that we do not know at the time.

psi123
User Rank
Rookie
re: Understand and characterize envelope-tracking power amplifiers
psi123   1/5/2012 12:01:00 AM
NO RATINGS
WKetel: Envelope tracking does not have to have Class "C" drivers and setting back the clock of the system. I do not want it to be represented as one of the unfinished ideas.

WKetel
User Rank
Rookie
re: Understand and characterize envelope-tracking power amplifiers
WKetel   1/4/2012 9:32:00 PM
NO RATINGS
Envelope tracking reminds me of the two modulated stages in an AM transmitter with class "C" driver and output stages. Much more efficient than anything linear. But more demanding on the output filtering section.



Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Curiosity Killed the Cat (Just Call Me Mr. Curiosity)
Max Maxfield
23 comments
My wife, Gina The Gorgeous, loves animals. She has two stupid dogs and two stupid cats. How stupid are they? Well, allow me to show you this video of the dogs that I made a couple of years ...

Martin Rowe

No 2014 Punkin Chunkin, What Will You Do?
Martin Rowe
Post a comment
American Thanksgiving is next week, and while some people watch (American) football all day, the real competition on TV has become Punkin Chunkin. But there will be no Punkin Chunkin on TV ...

Rich Quinnell

Making the Grade in Industrial Design
Rich Quinnell
13 comments
As every developer knows, there are the paper specifications for a product design, and then there are the real requirements. The paper specs are dry, bland, and rigidly numeric, making ...

Martin Rowe

Book Review: Controlling Radiated Emissions by Design
Martin Rowe
1 Comment
Controlling Radiated Emissions by Design, Third Edition, by Michel Mardiguian. Contributions by Donald L. Sweeney and Roger Swanberg. List price: $89.99 (e-book), $119 (hardcover).