[Amps] Modern AM Broadcast Transmitters

[donroden at hiwaay.net]

Modern AM Broadcast transmitters are pulse width modulated with the  
rated carrier power at 40% width of the pulses.

Negative modulation moves the pulse width towards zero pulse width
( carrier cut-off )

Positive modulation moves the pulse width towards full pulse width.
80% pulse width = 100% modulation or 4 x carrier power.

100% pulse width = 125% Positive modulation or 5 x carrier power.

Conventional Plate Modulation using audio transformers and Pulse Width
Modulation ( sometimes referred to as Pulse Duration Modulation or PDM )
looks identical on an oscilloscope and is detected identically with receivers.

Don W4DNR


DonR