A Consideration on the Switching Wave Form of a Doppler VOR Distributor

Abstract

The Doppler VOR compatible with the conventional VOR receiver is the most promising solution to the siting problems proper to the conventional VOR.

However, the Doppler VOR has the several operational problems caused by the unwanted RF radiations from the switching function of its distributor.

This paper describes analytical study on the optimum switching wave form to reduce the spurious radiation in the Doppler VOR.

Several switching wave forms are presented and discussed from such operational view points as adjacent channel interference, course error, etc.

The results indicate that; (1) the square wave switching has unacceptable defects, (2) the half sine wave switching is available for the existing Doppler VOR, and (3) the approximate sin x/x wave switching proposed here requires somewhat complicated circuits, but it will be most desirable for the futur precision VOR.