What does over-shoot mean? I heard of it in reference of using too large of a value of the coupling capacitor in a modulator heising configuration. Most of the circuits I have seen for 1 KW transmitters use a 1 UF cap at about 6 KV. In my Westinghouse MW-2 I have a 6 UF cap in there at 6 KV but I run it at 3200 volts. I used that cap because it was the only one I had with that high of a voltage rating. It's also floating above ground. Back to the question of "over-shoot", please don't shoot me for what otherwise may be a dumb question to many!
tnx Terry
"Overshoot" is also sometimes used to refer to what happens when an AM modulator does not perfectly reproduce a processed audio waveform.
Example: Your outboard audio peak limiter is adjusted so that a 1 kHz audio input signal just barely reaches 100% modulation. But your modulator frequency response has a +3 dB peak at 2 kHz. Every time your voice has significant 2 kHz components, your modulator will overshoot and overmodulate.
Overshoot can also be caused, paradoxically, by a frequency response
rolloff. On complex processed-audio waveforms, the output can sometimes approximate a square-topped wave. If your modulator frequency response is not flat down to a
very low frequency, the squared-off top will have a tilt imposed on it instead of being perfectly horizontal -- and this will also cause overshoot and overmodulation.
Bob Orban, who designed the Optimod series of audio processors, was of the opinion that to nearly eliminate overshoot, it's necessary for a modulator's frequency response to go down well into the subsonic range.
73,
Kevin, WB4AIO.
