{TAIL ~ The output} of {HEAD ~ the photodetector} or photodiode 5 is amplified, bandwith limited and then passed to an ADC 7 
{ TAIL ~ The output } of { HEAD ~ the photodetector } or photodiode 5 is amplified , bandwith limited and then passed to an ADC 7
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