| 摘要 |
PURPOSE:To modulate reference luminous flux and sample luminous flux to mutually different fequencies easily at low cost by providing one rotary chopper, a beam combiner, and a light shield part. CONSTITUTION:When shutters 17 and 18 are opened and the chopper 5 provided nearby the beam combiner 4 makes one turn, mixed luminous flux (R+S)/2 passes through it twice, the sample luminous flux S/2 passes once, a state D in which pieces of luminous flux R and S are both cut off is entered once, so the chopper 5 of frequency (f) rotates to modulate the mixed luminous flux (R+S)/2 to a frequency 2f and the sample luminous flux S/2 to the frequency (f). The output of a detector 8 is amplified by a preamplifier 9 and separated into S/2 and (R+S)/2 by band-pass filters 10 and 11. Those signals S/2 and (R+S)/2 are amplified by main amplifiers 12 and 13 and then digitized by A/D converters 14 and 15, and a CPU16 performs arithmetic operation to obtain the ratio S/R of the sample luminous flux S and reference luminous flux R. |
