Error estimates for free-decay damping measurements
Por:
Orduffa-Bustamante F., Boullosa R.R.
Publicada:
1 ene 1993
Resumen:
An estimate is presented of the errors introduced by digital sampling of an analog time signal when the logarithmic decrement method is used to measure damping. Some computer simulations were made in order to verify that the error estimate is adequate. Other factors that influence the error in the measured damping ratio, such as noise and the value of the damping ratio, are also studied by computer simulation. It is shown that, on average, the digital sampling error depends mainly on the total number of sampled points, but that it is affected also by the ratio between the sampling frequency and the frequency of the signal. Digital sampling errors combined with the errors introduced by different signal-to-noise ratios impose bounds to the values of the damping ratio that can be measured accurately. It is also shown that the optimun number of data points, when digital sampling error is combined with noise, varies according to the signal-to-noise ratios and the value of the damping ratio. A brief discussion of other decay methods compared to the logarithmic decrement method is also given. © 1993, Acoustical Society of America. All rights reserved.
Filiaciones:
Section de Acustica, Centro de Instrumentos, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70- 186, Mexico
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