Agilent Technologies 8453 Operator's Manual page 152

Theory of Operation
Firmware Description
Apply Stray-Light Correction
By default a stray-light correction is always used. However, for very fast
measurements stray-light correction can be turned off by the user interface
of the ChemStation software.
The stray light correction is automatically turned off by the software of the
handheld controller whenever low cycle times are set for data acquisition.
Absorbance Calculation and Averaging
In case stray-light correction is not applied, this part of the firmware is used
to calculate an absorbance spectrum, the logarithm of the intensity spectrum
of the reference is subtracted from the logarithm of the intensity spectrum of
the sample.
Spectral averaging is used for noise reduction. If an integration time of more
than 100 ms is used, multiple spectra—dependent upon the selected
integration time—are measured. Absorbance values of each wavelength are
averaged to form one absorbance spectrum with variance for each
wavelength.
Absorbance Run Buffer
Absorbance spectra with their variances are intermediately stored here if the
acquisition of spectra is faster than the processing and data communication
to the ChemStation (intensity values can also be stored for special purposes,
for example, diagnostic reasons.) or handheld controller.
Intensity Averaging
In case stray-light correction is applied, this part of the firmware is used.
Averaging of the intensity spectra is used for noise reduction. If an
integration time of more than 100 ms is used, multiple spectra—dependent
upon the selected integration time—are measured. Intensity values of each
wavelength are averaged to form one intensity spectrum with variance for
each wavelength.
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