What Is A Hammer Test Or Hammer Impact Test?

This is often also known as Modal Testing. It is a method of testing that allows us to calculate the natural frequencies (modes), modal masses, modal damping ratios and mode shapes…

Continue ReadingWhat Is A Hammer Test Or Hammer Impact Test?

Understanding Filter Characteristics

Recently when discussing with an engineering student the characteristics of filters, it became clear that some confusion exists around this subject area. This note attempts to explain the differences between types of filter and the effects of the parameters of those filters. (more…)

Continue ReadingUnderstanding Filter Characteristics

How Do I Downsample Data?

Sometimes we have digitised data at a much higher rate than we need. How can we downsample data? If I wanted to say halve the sample rate can I just throw away every other data point?

The answer is NO, except in pathological conditions where you know that there is no frequency content above the new Nyquist frequency.

(more…)

Continue ReadingHow Do I Downsample Data?