BE 4MX 50 Uses ‘Fourier Modulation’ Technique

BE has put a name on its new 50 kW AM transmitter, first reported here in July.
The company will show its 4MX 50 AM transmitter at the NAB Radio Show. The model name refers to a Fourier Modulation (4M) technique the company said it designed and hopes to patent.
It uses duty-cycle modulated RF to produce optimum efficiency over the 250 watt to 55 kW power range; BE says this eliminates the need for an additional low-power transmitter at night.
The company quotes its director of RF engineering, Richard Hinkle, as calling this is a “huge departure” from usual modulation techniques, one that he said “started with a ‘what-if’ question: What if we modulated RF devices directly and independently, so we didn’t need a modulator stage or to turn PA modules on and off?”
The transmitter can be used with either analog or digital AM operation. It also provides for a plug-in Exgine card for implementation of the next generation HD Radio configuration with the coding and processing at the studio.