FAQ

A:

PXI has always been a cost-efficient solution for functional test. There are two reasons for this. First, PXI leverages the production volumes of both PCI and PCI Express. That allows us to offer products with excellent performance at very competitive prices versus other standards. Second, PXI is a modular standard, and the infrastructure—such as the controller and power supplies—is distributed among system resources.

A:Modal testing is a form of vibration testing of an object where the natural (modal) frequencies, modal masses, modal damping ratios and mode shapes of the object under test are determined.

A modal test not only consists of an acquisition phase, but also of an analysis phase as well. The complete process is often referred to as a Modal Analysis or Experimental Modal Analysis.

There are several ways to do modal testing. The most widely used are Impact Hammer modal testing and Shaker modal testing. In both cases energy is supplied to the system with a known frequency content. Where structural resonances occur there will be an amplification of the response, clearly seen in the response spectra. Using the response spectra and force spectra, a transfer function can be obtained. The transfer function (or frequency response function (FRF)) is often curve fitted to estimate the modal parameters; however, there are many methods of modal parameter estimation and it is the study of much research.