Aircraft instruments

摘要

An aircraft-speed indicating instrument has an index which is movable against a scale to provide a reading of airspeed, and a digital indicator which is selectively operable to provide a digital reading of either Mach number or the airspeed. The index and the digital indicator are driven by respective control systems supplied with a multiplexed electrical signal containing information representative of both Mach number and airspeed. Each control system includes gating means which is operable to pass only those parts of the multiplexed signal necessary for the associated control means to provde the desired reading.