Module Filter -3 dB

The module filter is a built-in feature of the Analog-to-Digital converter, which attenuates the input signal, beginning at the specified frequency.

The module will attenuate the selected frequency by approximately -3 dB, or 0.707 of the applied amplitude. This selected frequency could also be referred to as the bandwidth of the module. An input signal with frequencies above the selected frequency will be attenuated more, while frequencies below this frequency will receive no attenuation at all.

In addition to frequency rejection, a by-product of the filter selection is the minimum sample rate that is available. For example, the 1000 Hz selection will not attenuate any frequencies less than 1000 Hz, but will allow sampling of all 16 channels within 18ms, while the 10 Hz selection will reject all frequencies above 10 Hz and will only allow sampling of all 16 channels within 488ms.

The module filter is a module-level selection that affects all channels. The 60 Hz selection is the default setting, which provides -3 dB rejection of 60 Hz, rejects noise frequencies above 60 Hz, and provides a default sampling time of 12ms for all 16 channels. For optimal 50 or 60 Hz line rejection, you should select the 10 Hz setting.