Correct Choice of Maximum Length Sequence in Nondestructive Testing

Abstract

Maximum Length Sequence has great potential as testing signal in non-destructive testing. Because its autocorrelation is almost a delta function, the sequence can be used for speed of sound assessment. Resulting Impulse response contains very similar data as Impact-echo. Unlike Impact-echo, where strike energy is limited by nonlinear effects, Maximum Length Sequence can deliver virtually unlimited energy over time. Length of the sequence and also signal generation rate is a curtail choice in order to achieve the best results.