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