Well, if there is any circuitry on the secondary (I doubt there is other then the pumping diode due to the HV...not many solid states around that can handle it)
The advantage would be that the secondary swings both ways and a standard rectifier bridge would give out double frequency but at 1/2 the voltage because an AC oscillation's voltage is the difference between the + and -...and using both outputs would give a greater potential difference....with that being said I would like to point out the pumping diode again...and how the way Stan shows it...the BEMF can only go one way

...so, again I would probably have to say that attempting to modulate the output in any way is a waste of time...(you want the output to oscillate freely in most RLC circuit....this is a non linear resonance though...so it's a lil different)
Now, if he used both sides of a signal B4 the secondary is another matter...I have read many patents and some say different things...but, some ARE different things
