In article , Robert Casey
wrote:

John Byrns wrote:

Yes, but the diode is driven from the low source impedance of the cathode
follower, not something on the order of 100k. Why not eliminate the
cathode follower and choose the diode detector load so that it looks like
100k to the IFT at 455 kHz?

The detector diode is a nonlinear load, where a resistor is. Not sure,
but the non linearity
might cause distortions in the IF transformer. In that the loading of
the IF transformer's Q
is varying, thus the bandwidth is varying.

Not a problem, the IF transformer acts like the electrical equivalent of a
big flywheel providing the energy needed for those current pulses into the
diode. Put a scope on the plate of the IF amplifier tube. If this didn't
work radio would be in big trouble since many/most/all transmitters, or at
least the old tube ones, depend on the same flywheel effect to work since
the final only delivers short pulses of current into the output circuit.


Regards,

John Byrns


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