CHAPTER 4 Data acquisition
33
Fig. 7. A ‘stepwise’ pattern after magnification of a chromatogram.
This phenomenon will not occur at the
integrator
output because this output is
purely analog and therefore, in principle, with infinite resolution.
Integrator vs. recorder output
In the pulse and the scan mode, only the recorder output is suitable for data
acquisition. In the DC mode both outputs can be used, in that case a choice
has to be made.
A specific advantage of the integrator output is the large dynamic range and
infinite resolution. It is an analog output which means that the resolution is
only limited by the integrator that is used. In most integrators this is
approximately 1 µV. The 12 bits recorder output has a maximum output
resolution of 500 µV.
Often, the
recorder
output is chosen for data acquisition thus offering the
possibility of smoothening by means of rise time filters (Fig. 8). The
advantage of having a clean signal from the
integrator
output is not always
recognised, or the possibility for smoothening data is not implemented in the
integration software.
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