To perform the detection and processing of an interferogram in order to provide a spectrum by providing an A/D converter for supplying the digital form of interferogram waveform.
A first resistor-capacitor(RC) filter 10 receives an interferogram signal, and a second RC filter 11 receives a reference stripe signal. The output of the RC filter 10 is supplied to an A/D converter 12, and the output of the RC filter 11 is supplied to an A/D converter 14. These converters 12, 13 are formed of digital sigma converters and digital filters. The signal from a high- speed clock part 15 is used to supply a sampling signal to the converters 12, 14 at a prescribed over sampling rate. A digital signal processor 18 (DSP) receives the output signals from the A/D converters 12, 13, and the output of the DSP 18 has digital form of the interferogram in the zero cross point of reference strips.
HOULT ROBERT ALAN
FORSTER MICHAEL
