Instrumentation and machines for dynamic tests

It has been shown that use of wide‐band instrumentation in dynamic mechanical measurements can reveal the presence of high‐frequency ringing and other mechanical defects in the wave form. The use of low‐pass filters to suppress electrical noise can hide such defects. It is therefore better to eliminate the electrical noise at the source. If the mechanical irregularities in the waveform are not tolerable, they must be removed by improving the design of the testing device. The drop tester described in this report illustrates one possible way in which this may be done.