| 摘要 |
PURPOSE:To remove vibration noise, by scanning a laser driving current by a wave form replaced in scanning order and rearranging collected signals in reverse order of a wavelength by a signal processing circuit to obtain an absorption spectrum. CONSTITUTION:The driving current value at the terminal of the long wavelength of a laser beam emitting element is set to I0 and the driving current value at the terminal of the short wavelength thereof is set to I0+L and a driving current width L is divided into N0 and, further, (N0) in L is divided into N1 and a driving current areas are set to formulae, that is, I0,..., I0+(N1-1)L/N, I0+L/N0,..., I0+L/N0+(N1-1)L/N1, I0+(N0/N1-1)L/N0,..., I0+(N0/N1-1)L/ N0+(N1-1)L/N10. As mentioned above, if the signal train collected by a signal processing circuit is rearranged in reverse order of a wavelength to calculate an absorption spectrum, the vibration noise of a freezer superposed to the signal train apparently becomes one half in its frequency by rearrangement. The noise of this cycle can be removed from the signal by filter processing.
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