For a highly precise measurement of even low light intensities for the purpose of reduction of the analysis time, {HEAD ~ each light source} is switched on and off during a defined interval by {TAIL ~ a clocked pulse sequence} of constant pulse frequency alternately 
For a highly precise measurement of even low light intensities for the purpose of reduction of the analysis time , { HEAD ~ each light source } is switched on and off during a defined interval by { TAIL ~ a clocked pulse sequence } of constant pulse frequency alternately
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH