Tam/WB2TT wrote:

You are only scratching the surface. Check out the Harris DX series of high
power AM transmitters. It will blow your mind away. Basically, the
instantanous RF output power is synthesized by turning on 0 to 64 fairly low
power (~KW) modules. I don't know what the sampling frequency is, but
probably 20 KHz.. All modules are driven by a square wave signal at the
carrier frequency. There is no modulator.

There is also a fractional stage - a 64 stage AM modulation would sound
quite nasty, so an analogue signal is added to make up.

There is also a 'spare stage' dthat can be switched in if one of the
stages fails.

Nice stuff, but the only really interesting thing IMO is the output
combiner. The rest is just 'how do we make this digital'.


Thomas