Abstract: Disclosed is an apparatus for enlarging the range of modulation frequencies that modulate the variable wavelength light generated by the light source without prejudice to the measurement of optical characteristics. A modified modulation frequency computing section computes modified modulation frequencies by multiplying by the initial modulation frequency fmin by the value obtained by dividing the given phase value by the phase difference between the first phase of the transmitted light resulting from the transmission through the DUT of the incident light of the first wavelength modulated by the initial modulation frequency fmin and the second phase of the transmitted light resulting from the transmission through the DUT of the incident light of the second wavelength modulated by the initial modulation frequency fmin.

Abstract: The object of the present invention is to provide apparatuses that enable to enlarge the range of modulation frequencies that modulate the variable wavelength light generated by the light source without prejudice to the measurement of optical characteristics.

Abstract: In a waveform analyzer directed toward enabling recognition at a glance whether displayed waveform data are within a desired range; waveform data converter 50 inputs waveform data stored in a waveform data memory 10 and the result of comparison of the waveform data stored in waveform data memory 10 with a judgment standard stored in limit line memory 20 at comparison operator 30; and based on the inputted comparison result, waveform data converter 50 converts to a predetermined format only that portion of the waveform data stored in waveform data memory 10 that is judged to be outside the desired range based on the judgment standard; following which waveform display device 40 displays the converted waveform data.