Campbell Scientific IRGASON Integrated CO2/H2O Open-Path Gas Analyzer and 3D Sonic Anemometer - Manual (Page 56)

Appendix A. Filter Bandwidth and Time Delay
The EC100 measures gas and wind data at 100 Hz, and 100 Hz data are down-
sampled to the datalogger scan rate through SDM communications (see Section
8, EC100 Outputs). This process synchronizes EC100 gas and wind data with
other signals measured by the datalogger to within ±5 ms (plus or minus one-
half of the inverse of 100 Hz). Alternatively, when sending data to a non-
Campbell data acquisition system, the EC100 down-samples its USB and RS-
485 outputs to a user-selectable rate of 10, 25, or 50 Hz. Although the gas and
wind data from the EC100 remain synchronized, the user must consider the
down-sampled output interval when synchronizing the EC100 data with other
measurements in their system. These slower output intervals increase the
asynchronicity of EC100 data with other system measurements.
FIGURE A-1. Frequency and amplitude response of EC100 filter at
various bandwidths
1 10 70
Hertz
0.0001
0.001
0.01
0.1
1
10
N
o U
ni
ts
5 Hz
10 Hz
12.5 Hz
20 Hz
25 Hz
EC100 Bandwidths (Amplitude Responses)
A-2