Providing Isolation, Amplification, Lowpass Filtering, and Simultaneous Sampling
Print
In many situations, an analog signal must be conditioned before is can be accurately acquired. Numerous types of signal conditioning exist. Isolation, amplification, and lowpass filtering are three types that are each extensively used.
Isolation and amplification are both provided by an isolation amplifier. This is an amplifier that provides electrically isolated inputs and outputs that let it amplify a differential signal that is superimposed on a high common-mode voltage. Lowpass filtering can serve many purposes, including both the prevention of aliasing (anti-aliasing) and the removal of high-frequency noise. A Bessel filter has a linear phase response in its bandpass that allows signal phase integrity to be maintained.
In addition to signal conditioning, the ability to simultaneously sample signals is often required. Simultaneous sampling refers to multiple analog signals being digitized at the same instant. This allows the phase relationships of these signals to be maintained.
Some applications require isolation, amplification, lowpass filtering, and the conditioned analog signals to be simultaneously sampled. To accomplish this task, signal conditioning and simultaneous-sampling hardware can be cascaded. The SCXI-1120 (isolation and amplification), SCXI-1142 (Bessel lowpass filtering), and SCXI-1140 (simultaneous sampling) can be used for this purpose.
Related Links:
SCXI Triple Cascade: SCXI-1120 to SCXI-1142 to SCXI-1140
Reader Comments | Submit a comment »
Legal
This tutorial (this "tutorial") was developed by National Instruments ("NI"). Although technical support of this tutorial may be made available by National Instruments, the content in this tutorial may not be completely tested and verified, and NI does not guarantee its quality in any way or that NI will continue to support this content with each new revision of related products and drivers. THIS TUTORIAL IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND AND SUBJECT TO CERTAIN RESTRICTIONS AS MORE SPECIFICALLY SET FORTH IN NI.COM'S TERMS OF USE (http://ni.com/legal/termsofuse/unitedstates/us/).