On 25/05/2010 01:55, walt wrote:
....
Or are you considering the output characteristic of the transmitter to
be non-linear? This is not the case, because the effect of energy
storage in the tank circuit isolates the non-linear input from the
output circuit, which is linear as evidenced by the almost perfect
sine wave appearing at the output of the tank.

Well, for the purposes of application of linear circuit theory,
linearity means that V is linearly related to I, or at least dV/dI over
the operating range is substantially constant.

If the circuit is not linear in those terms, then you cannot form a
valid Thevenin equivalent circuit, and discussion of the Thevenin
equivalent series source impedance is a nonsense... it cannot be used.

Owen