The undesired periodic noise is coupled via {TAIL ~ ground} and the battery into {HEAD ~ the signal processing path} 
The undesired periodic noise is coupled via { TAIL ~ ground } and the battery into { HEAD ~ the signal processing path }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD