| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the periodic noise by a method wherein interferograms which are output from an analysis part are sampled simultaneously by a plurality of gain amplifiers and, when data are synthesized, the ratio which is adopted by a data series is changed near the changeover of a gain. SOLUTION: An interferogram IF which is output from a detector 9 is amplified by a preamplifier 10 so as to be divided into two interferograms, the interferograms are input to a gain amplifier 31 and a gain amplifier 32 so as to be amplified, and they are sampled at the same timing, by separate A/D converters 33, 34 so as to be stored in memories 37, 38 at a computer 36. That is to say, data which is one times the value of the interferogram IF is stored in the memory 37, and data which is 16 times is stored in the memory 38. Then, two stored data series are synthesized and processed by a synthesis and processing circuit 39.</p> |
