Running thread parameter determining method for use in textile machine, involves transforming thread signals by fast Fourier-transformation into complex signal spectrums, and determining speed of thread from shift and distance of sensors

摘要

The method involves transforming thread signals, which are detected by optical sensors (6a, 6b), by a fast Fourier-transformation into complex signal spectrums. A common complex data field is formed from parts of the complex signal spectrums by a complex conjugated multiplication. The common complex data field is transformed back to a time domain by an inverse Fourier-transformation. Speed of a running thread (2) is determined from a temporal shift and distance of the sensors corresponding to a maximum complex data field.