| 摘要 |
<p>The apparatus includes a transducer (12) coupled to a wheel driven by the cable (4) to indicate the speed of travel of the cable. A calibration unit (18) converts this speed in collaboration with a nominal twist rate set into the unit, into an output signal having a frequency equal to the nominal twist frequency of the cable. A detection assembly (10) downstream of the wheel (6) detects the variations in thickness of the twisted cable as it passes and thus produces a signal having a frequency component directly related to the actual twist rate. An analyser (18) conducts a fourier analysis on the output of the detector and, with the aid of the nominal twist frequency, is able to select the frequency component representative of the actual twist frequency. The actual twist frequency is compared with the nominal twist frequency by a comparator (20) and the resulting difference signal is fed back to the twisting assembly.</p> |
