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Apparatus and method for electronic polarization correction

  • US 5,760,740 A
  • Filed: 08/08/1995
  • Issued: 06/02/1998
  • Est. Priority Date: 08/08/1995
  • Status: Expired due to Term
First Claim
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1. In a receiving system for receiving a first electromagnetic signal having frequencies within a given frequency channel and transmitted from an external source at a first polarization, said receiving system also receiving a second electromagnetic signal having frequencies within said given frequency channel and transmitted from an external source at a second, different polarization, a cross polarization cancellation apparatus for canceling received cross polarized energy of said second signal, comprising:

  • antenna means for receiving said first and second signals and for providing a first antenna output signal containing received energy arriving at said antenna means at said first polarization and a second antenna output signal containing received energy arriving at said antenna means at said second polarization;

    first circuit means for converting said first and second antenna output signals to first and second combiner input signals, respectively, with a controlled relative amplitude and a controlled relative phase with respect to one another;

    combining means for vectorially combining signal energies of said first and second combiner input signals to produce a combiner output signal;

    second circuit means for detecting signal energy of said combiner output signal at a predetermined frequency to provide a detected signal;

    said first circuit means being responsive to said detected signal to optimize said controlled relative amplitude and relative phase to provide said combiner output signal with signal energy associated substantially with said first electromagnetic signal, and substantially devoid of signal energy associated with said second electromagnetic signal;

    wherein said first circuit means is operable to continuously vary said relative amplitude and relative phase to produce time varying changes in said detected signal and said first circuit means includes;

    pseudo-noise generation means for continuously producing pseudo-random changes in said relative amplitude and relative phase; and

    correlation means coupled to said pseudo-noise generation means for correlating said time-varying changes in said detected signal with said pseudo-random changes to continuously optimize said relative amplitude and phase, thereby continuously optimizing cross-polarization rejection.

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