| 摘要 |
In one exemplar embodiment, a digital altitude encoder is provided that utilizes a conventional altimeter responsive to atmospheric pressure for rotationally driving an indicator shaft. Attached to the shaft is a disc having repetitive, alternate, regularly disposed solid portions and slots. A light source and a pair of light detectors for receiving light from the source are spaced adjacent the disc to permit one of the detectors to generate a first signal and the other detector to generate a second signal having a relative time of occurrence dependent on the direction of the rotation of the disc. A counting means that is presettable to a predetermined digital count representative of a preselected altitude function receives the first and second signals and increments or decrements the predetermined count in response to changes in altitude. A code conversion circuit receives the digital signal output from the counter and converts the digital signal to a parallel digital code acceptable for transmission of aeronautical altitude information.
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