| 摘要 |
Rotary type knotmeters designed to detect relative motion between an underwater vehicle and the water in which it is submersed at relatively great depths comprise a vaned rotor external unit, an electronic counter/display internal unit, a multiplexing transmission line connecting the external unit to the internal unit and, preferably, a brake unit to stop rotation of the rotor unit when the knotmeter is not immersed in water. The external unit comprises a plurality of spaced Hall-effect magnetic sensors that function with bi-phase electronic detectors to modulate current flowing in the transmission line to power the external unit. Such detectors count the number of rotations per unit time of the vaned rotor which is proportional to the relative motion between vehicle and water. The current is demodulated in the internal unit to produce a velocity value which is then displayed as a digital speed reading.
|
