| 摘要 |
<p>PCT No. PCT/GB87/00610 Sec. 371 Date Apr. 26, 1988 Sec. 102(e) Date Apr. 26, 1988 PCT Filed Sep. 2, 1987 PCT Pub. No. WO88/01726 PCT Pub. Date Mar. 10, 1988.A probe (12) is connected to an interface circuit (10). The probe (12) has two different types of contact sensors, namely a piezo electric sensor and an electro-mechanical switching sensor. The trigger signal from the piezo electric sensor is detected by circuits (34,36,38,40) while that from the switching sensor is detected by a comparator (32). The signals are mixed in a mixer (42) to produce a single output trigger signal. A monostable (48) and latch (50) discriminate which sensor produced the output signal, making use of the inherent time delay between the two sensor signals. Circuits (24,26,28) determine if a conventional switching probe has been connected instead of the probe (12). If so, a transistor (T4) varies the power supply to the probe, and gates (30,33) switch in a comparator (18) in place of the comparator (32).</p> |
