Shimadzu GC-2014 - Filter Signal Time Constant

13 Detector
13.3
13.
170
GC-2014
13.3Filter Signal Time Constant
Q Selecting the filter time constant
Normally, analysis can be performed with the time constant set to the default value (dual
FID, TCD: 1 s, single FID: 200 ms). In order to improve the S/N ratio, the time constant can
be changed by measuring the peak half width.
Fig. 13.3.1 shows the relationship between the peak half width and the time constant where
the S/N ratio is maximaized. For example, if the half width of a peak is “0.1 sec”, the S/N
ratio is maximaized when the time constant is set to “20 ms.”
Fig. 13.3.1 Relationship between time constant and S/N ratio
Half width 10 s
Half width 1 s
Half width 0.1 s
4 ms 5 ms
10 ms 20 ms 50 ms
100 ms 200 ms 500 ms
1 s 2 s
Time constant
Normalized SN ratio
0
0.2
0.4
0.6
0.8
1
1.2