Yes the filter caps on the target board in front of the LDO perform the job of holding up the voltage to the voltage regulator during the times that the power rail is switched off.

There are several considerations here:

1) Manchester is 50% duty cycle. To be conservative try to make sure that the filter caps stay properly charged under 50% duty cycle switching. Depending on how you setup the far end to detect the Manchester encoded current flow the sensor may limit the filter cap charge rate. This could be problematic if the sensor was a resistor with too much resistance.

2) Make sure that the target has a minimum current load so that the far end sensor sees current flow even though the the filter caps may be fully charged and the power switch FET is turned back on.

Depending on how much current flow you expect in the line one way to detect the current on the far end may be to use an opto coupler. Connect like this. Feed main current flow through 2 or 3 power diodes that are wired in series with the DC feed. Then place the opto's input LED across these three series diodes but with a small resistor in series with it to limit the opto LED current. The three series power diodes limit the total voltage drop to feed impress across the opto LED.

Michael Karas