When the first number of {HEAD ~ shock events} exceeds an upper event threshold, a control signal is adjusted in order to adjust a frequency spectrum of noise affecting {TAIL ~ the shock detector} 
When the first number of { HEAD ~ shock events } exceeds an upper event threshold , a control signal is adjusted in order to adjust a frequency spectrum of noise affecting { TAIL ~ the shock detector }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL