What is digital low-pass filter?
A lowpass filter is one which suppresses or attenuates the high frequency components of a spectrum while 'passing' the low frequencies within a specified range. From: Digital Signal Processing (Second Edition), 2006.
Which low-pass filter is best?
A capacitive low-pass filter requires an extra resistance in series with the source, whereas the inductive low-pass filter does not. In the design of a high-current circuit like a DC power supply where additional series resistance is undesirable, the inductive low-pass filter is the better design choice.