| 摘要 |
<p>The diameter of an optical fibre (10) being drawn is monitored and controlled by an optical measuring technique. An electrical input signal is generated by a detector (18) from the fringe pattern produced by directing a laser beam (14) onto the fibre (10). The input signal is connected to appropriate terminals of first, second, third and fourth comparators (36, 38, 51, 52). The input singal is delayed 180° by a delay circuit (40) to provide an input signal to the remaining two terminals of the first and second comparators (36, 38) and is delayed 90° by a delay circuit (54) to provide an input signal to the remaining terminals of the third and fourth comparators (51,52). The output pulses from the comparators are shaped by pulse shapers (46, 48, 56, 58), summed by summers (50, 60, 64) and counted by counter (68) to provide a control signal forthe fibre drawing apparatus (16).</p> |
