| 摘要 |
To prevent an infra-red communications transmitter being observed by someone wearing night vision goggles, the transmitter is operated at a frequency outside the operating range of the goggles, eg > 1100nm. The transmitter forms part of a transceiver, which may be fitted to an aircraft in the vicinity of its strobe light. Preferably the transmitter emits pulses whose repetition frequency is modulated to convey speech information; statistical data can be superimposed in almost imperceptible data packets. |
