An Assembly Language Program for Calculating Random Decrement Signatures.
AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA)
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Random decrement signatures are widely usd in vibration analysis such as the testing of aircraft structures both in flight and on the ground. A method of calculating such a signature has been programmed in assembly language for a NOVA 3 computer using data transfered from a NICOLET FFT analyser. The program was written for a mini-computer so that it could be used for in-the-field analysis. As the method involves a large amount of data manipulation, assembly language was used, instead of Fortran, because it is more efficient in terms of speed and storage. The input analog signals to the analyser are transfered to the computer after digitising. The signatures calculated are displayed on an oscilloscope using the digitalanalog converters in the analyser. The final result can be plotted on a digital plotter. After the signatures have been calculated the power spectra are determined using Fourier analysis. The analyser is used to perform the Fourier transforms as this is faster than the algorithm on the NOVA 3. The program runs interactively allowing the operator to terminate the random decrement averaging process when desired. The results obtained from random vibration test on a CT4 tailplane, are given as an example of graphical output from this program.
- Computer Programming and Software
- Computer Hardware