| 摘要 |
Optical multiplexing systems are known in which a source supplies radiation to a detector via several optical sensors arranged in parallel with one another. The path between the source and detector via each sensor is different so that the sensors can be identified. In the present invention, the source is modulated at a number of different frequencies, the number being equal to that of the sensors. The output of the detector is fed to one input of a number of mixers, one for each frequency. The other input of each mixer receives a different one of each of the frequencies so that each mixer produces an output representative of different ones of the sensors.
|
