Claims
- 1. A cross polarization interference eliminating apparatus comprising, independently with respect to first and second polarized waves:
- demodulator means for demodulating by a quasi-synchronous detection system one polarized wave out of the first and second polarized waves which are received and have a cross polarization relationship;
- a transversal equalizer carrying out a wave equalization with respect to an output demodulated data of said demodulator means;
- a reference signal generating circuit generating a reference signal which is eliminated of phase rotation based on phase rotation control information and baseband signal obtained from a part of the demodulator means on the side of the other polarized wave of said demodulator means;
- a cross polarization interference canceler generating an interference canceling signal corresponding to an interference wave component included in the output demodulated data of said demodulator means based on the reference signal obtained from said reference signal generating circuit;
- an adder circuit outputting demodulated in-phase signal and quadrature signal by adding the output interference canceling signal of said cross polarization interference canceler to the output demodulated data of said transversal equalizer; and
- a controller generating a phase rotation control signal from the output in-phase signal and quadrature signal of said adder circuit and feeding back the same to said demodulator means.
- 2. The cross polarization interference eliminating apparatus as claimed in claim 1, wherein said reference signal generating circuit includes an identifying circuit identifying the baseband signal from the demodulator means on the side of said other polarized wave by one polarization signal clock, a retiming circuit carrying out a retiming process with respect to the phase rotation control signal from said controller on the side of the other polarized wave, and a phase rotation circuit outputting said reference signal by eliminating phase rotation of an output signal of said identifying circuit based on an output signal of said retiming circuit.
- 3. The cross polarization interference eliminating apparatus as claimed in claim 1, wherein said reference signal generating circuit includes an identifying circuit identifying the baseband signal from the demodulator means on the side of said other polarized wave by one polarization signal clock, a digital-to-analog converter subjecting the phase rotation control signal from said controller on the side of the other polarized wave to a digital-to-analog conversion in response to said other polarization signal clock, an analog-to-digital converter subjecting an output analog signal of said digital-to-analog converter to an analog-to-digital conversion in response to said one polarization signal clock, and a phase rotation circuit outputting said reference signal by eliminating phase rotation of an output signal of said identifying circuit based on an output signal of said analog-to-digital converter.
- 4. The cross polarization interference eliminating apparatus as claimed in claim 3, which comprises an automatic amplitude control circuit provided on an input side or an output side of said analog-to-digital converter and limiting the output signal amplitude to a predetermined value when an input signal phase changes by a predetermined value or greater.
- 5. The cross polarization interference eliminating apparatus as claimed in claim 3, which comprises an offset control circuit provided on an input side or an output side of said analog-to-digital converter and reducing an offset voltage.
- 6. The cross polarization interference eliminating apparatus as claimed in claim 1, wherein said reference signal generating circuit includes a digital-to-analog converter subjecting the output demodulated data of said demodulator means on the side of the other polarized wave to a digital-to-analog conversion in response to a polarization signal clock on the side of the other polarized wave, and an analog-to-digital converter outputting as said reference signal a digital signal which is obtained by subjecting an output analog signal of said digital-to-analog converter to an analog-to-digital conversion in response to a polarization signal clock on the side of the one polarized wave.
- 7. The cross polarization interference eliminating apparatus as claimed in claim 3, which comprises a phase locked loop circuit provided on an output side of said analog-to-digital converter.
Priority Claims (3)
Number |
Date |
Country |
Kind |
4-140721 |
Jun 1992 |
JPX |
|
4-140722 |
Jun 1992 |
JPX |
|
4-229693 |
Aug 1992 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 08/190,067, filed as PCT/JP93/00735 Jun. 1, 1993.
US Referenced Citations (15)
Foreign Referenced Citations (3)
Number |
Date |
Country |
59-107656 |
Jun 1984 |
JPX |
3254523 |
Nov 1991 |
JPX |
423632 |
Jan 1992 |
JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
190067 |
Feb 1994 |
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