Leonard Kahn developed one of

[bandit]

Leonard Kahn developed one of the competing systems for AM Stereo… it was superior to all others, but lost…

Later in his career, as a method to save AM, he developed the Powerside….

http://www.broadcastengineering.info/viewtopic.php?f=2&t=3124

http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=7313&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D7313