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Old February 16th 06, 03:28 PM posted to rec.radio.amateur.antenna
Reg Edwards
 
Posts: n/a
Default New Program: OP_ANGLE

To anyone who may be interested.

In the notes to this new program I omitted to say that the computed
components of plate current constitute the first few significant terms
of a Fourier Series.

There's the DC component, the fundamental frequency component, and the
2nd, 3rd, 4th and 5th harmonic components.

The amplitude of the harmonics decrease as the harmonic order
increases. Amplitudes are the peak sinewave values (not rms).

If the components, including the DC component, are added together
taking into account their signs, then their sum is very nearly equal
to the computed peak instantaneous plate current. Which has been
adjusted to equal the actual value which flows in the tube.

If the Fourier Series had been extended to even higher harmonics then
the sum of the series would have converged to the peak instantaneous
value of plate current exactly.

This is a check on the accuracy of the Fourier Analysis performed by
the program. There's ample oportunity for bugs.

If an amplifier is used as a frequency multiplier then power can be
extracted from the plate by an LC circuit tuned to the required
harmonic.

The correct plate load impedance is the required peak RF volts across
it divided by the peak amplitude of the plate current component.
There is NOT a conjugate match. The internal resistance of PA's is
NOT 50 ohms as is commonly believed. With pentodes, beam tetrodes and
transistors (transistors have operating angles) it is often much
higher.

There, I've said it again!
----
Reg, G4FGQ.