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