[time-nuts] PN/AM and 1.5Hz spur from frequency doubling?

Bill Byrom time at radio.sent.com
Thu Jan 19 15:39:24 EST 2017

I see spurs at 50 Hz and harmonics, which I assume are from the power
line at your location. This might be due to an oscillation in the power
supply regulator, leading to nonlinear regulator operation and
feedthrough of power line ripple. For example, low dropout regulators
can sometimes oscillate when an additional ceramic bypass capacitor is
added due to decreased phase margin in the feedback loop. It's also
possible that there is too much ripple before the regulator and you are
exceeding the dropout voltage, or that the regulator is going in and out
of an overcurrent condition. Many odd things may happen if the power
supply regular isn't working properly.


Bill Byrom N5BB

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