Abstract: A timing circuit receives substantially square wave clock signals and generates Sine and Cosine driving signals therefrom at a predetermined frequency for application to first and second mutually perpendicular Hall effect generators. The output signals from the Hall effect generators are algebraically summed to provide a heading signal, the phase displacement of which with respect to the driving signals, is representative of the orientation angle between one of the Hall effect generators and magnetic north. A counter is synchronized to begin to count clock pulses at the beginning of each period of the driving signals. A logic circuit is effective to disable the counter when the count therein is representative of the orientation angle. The count is stored in a memory and displayed on a readout device which is, in turn, updated at the end of each period of the driving signals' frequency.