In Doherty's day, within the Western Electric product line, the eponymous electronic device was operated as a linear amplifier with a driver which was modulated.
[4] Early Continental Electronics designs, by James O. Weldon and others, retained most of the characteristics of Doherty's amplifier but added medium-level screen-grid modulation of the driver (317B, et al.).
As in Doherty's amplifier, the tubes' source (driver) and load (antenna) were split and combined through +90 and −90 degree phase-shifting networks.
In addition, as the tetrode carrier and peak tubes required very little drive power, a significant improvement in efficiency within the driver was achieved as well.
Nearly 300 CE 317C transmitters were installed in North America alone, easily outdistancing all competitors combined, until the introduction of high-power transistorized designs by others, at which point CECo withdrew from this market.