W9GR QEX Article on CESSB

Paul Christensen, W9AC

Flex users who subscribe to QEX may want to pay particular attention to the recent ground-breaking article by Dave, W9GR (See QEX, Nov/Dec. 2014,  pp.3-13). 

Dave is the developer of the Controlled-Envelope SSB (CESSB) system used in recent versions of SSDR.  Yes, there's some complex math presented in the article, but even those Flex users without an advance math background should be able to understand his digital peak control processing method.   

I first met Dave back in the early '80s when he worked for Harris Broadcast.  He developed a popular method of effectively controlling FM modulation overshoot and filter ringing that occurs when peak amplitude protection is used between a stereo generator and FM exciter.   He's expanded on some of those ideas to include SSB modulation control and CESSB is his result.

Having read through the article -- as well as a description of Dave's recent DTV projects, he would be a highly useful player to help Flex accelerate the integration of adaptive pre-distortion (APD) into SSDR and the companion Flex firmware.

The QEX article is one of a few outstanding articles that comes along every decade or two.  Gerald's SDR introduction back in 2004 is certainly another. 

Paul, W9AC

KY6LA_Howard

http://www.arrl.org/files/file/QEX_Next_Issue/2014/Nov-Dec_2014/Hershberger_QEX_11_14.pdf

Ken - NM9P

Thanks, Howard. Interesting read.