the pressure determination system is operable to determine {HEAD ~ the pressure values} by determining {TAIL ~ a first pressure value} and a second pressure value of the fluid at a first time and a second time, respectively, during the oscillation of the pressure, and 
the pressure determination system is operable to determine { HEAD ~ the pressure values } by determining { TAIL ~ a first pressure value } and a second pressure value of the fluid at a first time and a second time , respectively , during the oscillation of the pressure , and
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH