[Amps] Liquid cooling

[Fuqua, Bill L]

  The problem with the Class-E with envelope restoration is primarily when amplifying complex spectrally non-symmetric signals such as SSB. They would work fine with AM signals.
May work fine with a single or two tone test under the right conditions but ends up to reconstruct a SSB signal the RF zero crossings must match up with the amplitude changes. Remember the old Central Electronics exciters. They had two balanced modulator adjustment on the front panel. 
  One you could unbalance for AM and the other you could unbalanced for Phase Modulation. 
Well, anyway the problem is that the Modulator for the envelope restoration has substantial delay if it is a switching device. 
That delay is usually longer than the 1/BW where the BW is the bandwidth of the signal. In the G2DAF amplifiers solve the problem on the most part
by using a detector that directly modulated the screen grid which has a short time constant. But, these solidstate devices don't have a screen grid. You could go to a linear modulator and solve the problem but by doing that you have defeated the whole reason by using a class-E modulator. 
  You could match up the delays possibly but it is not practical to have millisecond RF delays into the Class E amplifier.
If these phase and amplitude information does not match up other frequencies are produced including the some on the opposite side of the suppressed carrier. 
   There has been an attempt to put one on the ham market but it was taken off the market due to a "connector problem". But I think they found thisfundamental flaw in their design. I suspect that there were broad signal reports when these were actually used in voice applications even though the 
two tone test looked OK.
73
Bill wa4lav