Automatic direction finding system
US4219821A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1978 |
| Grant date | Aug 26, 1980 |
| Priority date | — |
| Expiry date | Sep 7, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S3/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An automatic direction finding (ADF) system including a direction finding antenna array which connects to a radio receiver to process an audio output signal selectively illuminating a segment of a segmented circular visual directional display indicating the direction from which the received signal arrived. In an FM version, the ADF system electronically switches between antennas in the direction finding antenna array alternately incorporating vector information onto the received carrier in a manner that can be phase detected to produce an audio frequency signal within the normal pre-audio bandpass of the receiver. The audio frequency is then demultiplexed to produce separate vector signals. These separate vector signals are then processed for selectively illuminating a segment of the segmented circular visual directional display. When a sufficiently strong signal is not being received, the ADF system sequentially illuminates each segment of the segmented circular visual directional display in a clockwise direction at a rate which can be readily and visably perceived by an operator. This operation conveys the image of circuit activity, is exciting for an operator to watch, and may h…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.