Sensornet ORYX DTS, Руководство пользователя

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Oryx DTS User Manual v4 Page 57
Figure 39 - Length (dispersion) correction correct
Setting the Measurement Range
The next screen allows the user to specify the measurement range. The maximum
fibre length is measured by default but the user can reduce the range to avoid
unnecessary data being collected (and reduce data transfer times). Temperature
data beyond the end of the fibre typically appears as very large amplitude noise (-
200 to +700°C). The graphical zoom buttons can be u sed to zoom in on the end of
the fibre or end of the region of interest to help set the maximum measurement
range.
Differential loss correction – Single ended
The next stage is to set the method of ‘differential loss’ correction. This is required
to correct for the slightly different loss in the fibre of the Stokes signal compared to
the anti-stokes signal which may vary from fibre to fibre. For a continuous length of
fibre at constant temperature, this differential loss correction appears to affect the
slope of temperature vs. distance (hence it is referred to as ‘slope correction’). In
this section, single-ended correction will be assumed (i.e. only one end of the fibre
connected to the DTS). For the alternative ‘combined’ or ‘double-ended’ correction,
please see section 0, page 68.