Harmonics.
http://www.fluke.com/fluke/twen/solutions/pq/troubleshooting-power-harmonics.htm
http://www.psihq.com/iread/harmonic.htm
Is DC offset the product of harmonics?
.
http://www.fluke.com/fluke/twen/solutions/pq/troubleshooting-power-harmonics.htm
http://www.psihq.com/iread/harmonic.htm
Is DC offset the product of harmonics?
.