Periodic and Random Deviation. A term used to describe the sum of all ripple and noise components measured over a specified bandwidth and stated in either peak-to-peak or RMS values.
PARD stands for “periodic and random deviation.” Used as a term for noise and ripples. Noise is unwanted output deviation and a ripple is an undesired portion of an output that is harmonically related in frequency to internal frequencies of switching or the frequency of an input line.
Acronym for "periodic and random deviation" and used as the specification term for ripple and noise. Ripple is the unwanted portion of the output harmonically (periodically) related in frequency to the input line and to any internally generated switching frequency. Noise is the unwanted, aperiodic output deviation.