LI-COR LI7200RS, Instruction Manual

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Total System Delay Examples
Total System Delay (ms) = Delay Time + (Delay Step × Delay Step Increment)
Output Delay Time
(ms) Delay Step
(ms) Delay Step
Increment Total Delay
(ms)
DAC 172 6.667 19 299
SDM/RS-
232/Ethernet 130 6.667 25 297
Bandwidth
Bandwidth (5, 10 or 20 Hz) determines the signal averaging done by the digital fil-
ter. To avoid aliasing (only a concern for co-spectra, not for fluxes),
one should
sample the gas analyzer at a frequency greater than or equal to 2 times the
bandwidth
. Thus, if you are sampling at 10 Hz, the bandwidth is 5 Hz.
Bandwidth is the frequency at which the indicated amplitude is 0.707 of the real
amplitude (
Figure 7-1 below).
Figure 7-1. Bandwidth = 1/oscillation period.
Bandwidth is a useful indicator for characterizing real-world behavior in which
there are fluctuating gas concentrations. Given a sinusoidal oscillation of con-
centration, the instrument's ability to measure the full oscillation amplitude dimin-
ishes as the oscillation frequency increases.
Section 7. Software Reference
7-19 Total System Delay Examples