Automatic calibration system for distance measurement receivers

摘要

A receiver time delay calibration device designed for low cost retrofitting of airborne equipment and more specifically DME equipment. In this system, the output of a VFO is applied to the RF input port of the receiver to be tested. The VFO is swept through a frequency range of the receiver until the receiver provides an output, which occurs at the operating frequency of the receiver, ft. The receiver's output at ft is used to stop the sweep of the VFO and maintain it at ft. The output of the VFO is then pulse modulated and the delay between the RF pulse applied to the input of the receiver and the corresponding video output pulse from the receiver is measured to determine the receiver delay time.