{TAIL ~ The output signal} of {HEAD ~ the transducer} is amplified and then processed by a data processing unit to calculate the propane gas concentration 
{ TAIL ~ The output signal } of { HEAD ~ the transducer } is amplified and then processed by a data processing unit to calculate the propane gas concentration
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH