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