Topband: Waveshape Filters

Tom Rauch w8ji at contesting.com
Tue Jan 27 20:59:01 EST 2004


When I was playing with op-amp filters and a linear modulator, I found a
four section op-amp in a 100Hz low pass with each section's Q just over 1
was an almost perfect compromise between rise and fall time, envelope
overshoot, and bandwidth.

The problem with overshoot is it sets the peak envelope power, so the
average power has to be reduced. Amplifiers with unregulated supplies also
normally add some leading edge overshoot because they have more HV at the
start of each CW string.

Choke input supplies really give funny shapes, but don't add clicks.

73, Tom W8JI




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