Interference Canceling System.
DEPARTMENT OF THE ARMY WASHINGTON DC
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The described system utilizes a pair of antenna beam patterns, one of which is adapted to provide the desired signal and all interfering signals, and the other of which is adapted to provide only the interfering signals. The patterns are then combined to produce substantially only the desired signal as the combined output. As is well known and understood, one of the major concerns of designers of antenna system communication links is the elimination or reduction of external interference sources, such as jamming, self-interference, atmospheric noise, man-made noise, and acoustic noise. As is also well known, most of the arrangements which attempt to resolve these problems of external interference do so in a relatively complex manner, often times utilizing very large directional antennas andor with antennas having hundreds, or even more, elements. This problem of external interference is especially prevalent in the area of mobile communications systems where omnidirectional antennas are employed, because of the large numbers of users operating in the same frequency band and because of multipath. Use of very large directional antennas in such mobile arena will be seen to be almost a physical impossibility, and an economic impracticality.
- Radiofrequency Wave Propagation