RE: vv Critical rise time,

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>

Hi Bob,

I know we are getting down to semantics here, but if modulation -is-
multiplication, I think we are modulating. In breaking the circuit
(with, insert switching method of choice here) we are effectively
multiplying the waveform alternately by 1, or 0.

Put another way, repeating a waveform is no different than the digital
modulation employed on many of the communication methods we use today.
One amusing example I saw was that of a blanket modulating a smoke
stream.

If we resort to the IEEE definitions, essentially any variation of any
parameter of a waveform or signal is considered as modulation.

Now that's twice I have resorted to pulling out the IEEE purple book :)

Leigh



Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

Hi Leigh,

 > Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>

snip

 > Modulating or more accurately repeating at the break rate is the same
as
 > convolving (in the time domain) by a series of impulses with a period
 > equal
 > to the break rate. Which is the same as multiplying the spectrum by a
 > series
 > of impulses. Which just turns the continues spectrum of a single
break
 > into
 > a discrete one with components separated by the break frequency.
 >
 > <LC> It's been a while since I looked at this properly, so entertain
me
 > for a moment; would repeating at the break rate not (by definition)
be
 > the same as modulation by a pulse train? So it then becomes the
 > convolution of a pulse train and the resonant frequency of the tank.
 > (assuming as we stated above, lumped parameters in the TC).

No to repeat a particular waveform is not the same as modulation if
modulation means multiplication.
Repeating a particular waveform is equivalent to convolution with a
train of
impulses with a period equal to the rep rate.
I suspect that you are thinking about a continuous waveform and are
chopping
it up.

 >
 > I agree the spectrum of a self excited burst mode SSTC could be
tricky.
 >
 > <LC> I guess in the case of the SSTC with feedback you would have to
 > either assume steady state operation, (or use chaos theory as in the
 > higher order simulation of a phase locked loop).

I believe that modern SSTG operate in small (relative to transient
decay)
bursts so the start transient is significant i.e. they never achieve the
steady state response that can be easily obtained from the transfer
function. So there would be very significant errors in assuming steady
state.

Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400