Adaptive interference reduction system for crosstalk cancellation in a dual polarization system
First Claim
1. An adaptive correction network for decoupling a first and second signals comprising:
- a first adjustable filter receiving said first signal and adjusting its weight and phase;
a second adjustable filter receiving said second signal and adjusting its weight and phase;
first adder means for adding said first signal and the weighted and phase adjusted output from said second adjustable filter to thereby subtract cross-coupling components from said first signal;
second adder means for adding said second signal and the weighted and phase adjusted output from said first adjustable filter to thereby subtract cross-coupling components from said second signal;
first noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said first adder means;
second noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said second adder means; and
control means for generating signals in accordance with the signals generated by said first and second noise-to-signal measuring means to control said first and second adjustable filters;
wherein said first and second noise-to-signal measuring means each comprise;
a slow response control circuit for maintaining the average value of the input signal from said adder means at approximately a reference value;
means for filtering said average signal to remove signal components not caused by cross-coupling with another signal; and
detector means for detecting fluctuations remaining in said signal after filtering and generating a signal proportional to these fluctuations.
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Abstract
An adaptive interference reduction system for removing cross talk from a dual polarization system comprising a first adjustable filter for varying the phase and the weight of a first input signal, a second adjustable filter for varying the phase and the weight of a second input signal, a first adder for adding this first input signal and the weighted and phase adjusted output from the second adjustable filter, a second adder for adding the second input signal and the weighted and phase adjusted output from the first adjustable filter, a first noise-to-signal measuring device for generating a signal proportional to the noise-to-signal ratio in the output signal from the first adder, a second noise-to-signal measuring device for generating a signal proportional to the noise-to-signal ratio in the output signal from the second adder, and a dither-type control logic for dithering in-phase and quadrature square-waves in accordance with the signals generated by the first and second noise-to-signal measuring devices to control the first and second adjustable filters. This system is further characterized in that the first and second noise-to-signal measuring devices comprise a slow response control circuit for maintaining the average value of the input signal from the adder at a reference value, and means for filtering this averaged value and detecting the power fluctuations remaining in the signal and generating a signal proportional to these fluctuations. Additionally, the first and second adjustable filters may be structured to have transfer functions across a predetermined bandwidth of W0 [1+W1 ω+W2 ω2 ] or W0 [1+W1 ω+W2 ω2 +W3 ω3 ], where W0 , W1, W2 and W3 are signal weights and ω represents the frequency variation of the input signal from its carrier.
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Citations
36 Claims
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1. An adaptive correction network for decoupling a first and second signals comprising:
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a first adjustable filter receiving said first signal and adjusting its weight and phase; a second adjustable filter receiving said second signal and adjusting its weight and phase; first adder means for adding said first signal and the weighted and phase adjusted output from said second adjustable filter to thereby subtract cross-coupling components from said first signal; second adder means for adding said second signal and the weighted and phase adjusted output from said first adjustable filter to thereby subtract cross-coupling components from said second signal; first noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said first adder means; second noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said second adder means; and control means for generating signals in accordance with the signals generated by said first and second noise-to-signal measuring means to control said first and second adjustable filters; wherein said first and second noise-to-signal measuring means each comprise; a slow response control circuit for maintaining the average value of the input signal from said adder means at approximately a reference value; means for filtering said average signal to remove signal components not caused by cross-coupling with another signal; and detector means for detecting fluctuations remaining in said signal after filtering and generating a signal proportional to these fluctuations. - View Dependent Claims (2, 3, 4)
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5. An adaptive correction network for decoupling a first and second signals comprising:
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a first adjustable filter receiving said first signal and adjusting its weight and phase; a second adjustable filter receiving said second signal and adjusting its weight and phase; first adder means for adding said first signal and the weighted and phase adjusted output from said second adjustable filter to thereby subtract cross-coupling components from said first signal; second adder means for adding said second signal and the weighted and phase adjusted output from said first adjustable filter to thereby subtract cross-coupling components from said second signal; first noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said first adder means; second noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said second adder means; and control means for generating signals in accordance with the signals generated by said first and second noise-to-signal measuring means to control said first and second adjustable filters; wherein said first and second adjustable filters each comprise; first means for generating a signal from an input signal which is constant in magnitude and phase; second means for generating from said input signal a signal with magnitude and phase terms which vary linearly with frequency across a predetermined frequency bandwidth, the precise linearity variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said control means; third means for generating from said input signal a signal with magnitude and phase terms which vary quadratically with frequency across said predetermined frequency bandwidth, the precise quadratic variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said control means; third adder means for combining the output signals from said first, second and third means for application to said first or second adder means. - View Dependent Claims (6, 7, 8)
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9. A noise measuring device for measuring the cross-coupling components in an automatic decoupling system comprising:
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a slow response control circuit for maintaining the average value of an input signal at approximately a reference value; means for filtering said averaged signal to remove signal components not caused by cross-coupling with another signal; and detector means for detecting fluctuations remaining in said signal after filtering and generating a signal proportional to these fluctuations. - View Dependent Claims (10, 11, 12)
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13. An adjustable filter for use in adaptively removing cross-coupling signal components in a channel under the control of an automatic decoupling system comprising:
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first means for generating from an input signal a signal which is constant in magnitude and phase; second means for generating from said input signal a signal with magnitude and phase terms which vary linearly with frequency across a predetermined frequency bandwidth, the precise linearity variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said automatic decoupling system; third means for generating from said input signal a signal with magnitude and phase terms which vary quadratically with frequency across said predetermined frequency bandwidth, the precise quadratic variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said automatic decoupling system; first adder means for combining the output signals from said first, second and third means for application to the channel to be decoupled. - View Dependent Claims (14, 15)
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16. An adaptive correction network for decoupling a first and second signals comprising:
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a first adjustable filter receiving said first signal and adjusting its weight and phase; a second adjustable filter receiving said second signal and adjusting its weight and phase; first adder means for adding said first signal and the weighted and phase adjusted output from said second adjustable filter to thereby subtract cross-coupling components from said first signal; second adder means for adding said second signal and the weighted and phase adjusted output from said first adjustable filter to thereby subtract cross-coupling components from said second signal; first noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said first adder means; second noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said second adder means; and control means for generating signals in accordance with the signals generated by said first and second noise-to-signal measuring means to control said first and second adjustable filters; wherein said first and second adjustable filters each comprise means for varying an input signal by the function W0 [1+W1 ω
+W2 ω
2 ], where ω
is measured from the carrier frequency of the input signal and wherein W0, W1, and W2 are weights controlled by signals from said control means. - View Dependent Claims (17, 18)
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19. An adjustable filter for use in adaptively removing cross-coupling signal components in a channel under the control of an automatic decoupling system comprising:
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first adder means; first delay means for delaying said input signal by a predetermined amount and applying its output to said first adder means; second delay means for delaying the output signal from said first delay means by a predetermined amount; first subtractor means for subtracting the output signal from said second delay means from said input signal and applying this subtracted output signal to said first adder means; second adder means for adding the output signal from said second delay means to said input signal; and second subtractor means for subtracting the output signal from said first delay means from the output signal from said second adder means and applying this subtracted output signal to said first adder means; said first adder means adding the output signals from said first delay means, said first subtractor means, and said second subtractor means and applying its output to the channel to be decoupled. - View Dependent Claims (20)
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21. An adaptive correction network for decoupling a first and second signals comprising:
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a first adjustable filter receiving said first signal and adjusting its weight and phase; a second adjustable filter receiving said second signal and adjusting its weight and phase; first adder means for adding said first signal and the weighted and phase adjusted output from said second adjustable filter to thereby subtract cross-coupling components from said first signal; second adder means for adding said second signal and the weighted and phase adjusted output from said first adjustable filter to thereby subtract cross-coupling components from said second signal; first noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said first adder means; second noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said second adder means; and control means for generating signals in accordance with the signals generated by said first and second noise-to-signal measuring means to control said first and second adjustable filters; wherein said first and second adjustable filters each comprise; first means for generating a signal from an input signal which is constant in magnitude and phase; second means for generating from said input signal a signal with magnitude and phase terms which vary linearly with frequency across a predetermined frequency bandwidth, the precise linearity variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said control means; third means for generating from said input signal a signal with magnitude and phase terms which vary quadratically with frequency across said predetermined frequency bandwidth, the precise quadratic variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said control means; fourth means for generating from said input signal a signal with magnitude and phase terms which vary cubically with frequency across said predetermined frequency bandwidth, the precise cubic variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said control means; and third adder means for combining the output signals from said first, second, third and fourth means for application to said first or second adder means. - View Dependent Claims (22, 23, 24, 25)
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26. An adaptive correction network for decoupling a first and second signals comprising:
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a first adjustable filter receiving said first signal and adjusting its weight and phase; a second adjustable filter receiving said second signal and adjusting its weight and phase; first adder means for adding said first signal and the weighted and phase adjusted output from said second adjustable filter to thereby subtract cross-coupling components from said first signal; second adder means for adding said second signal and the weighted and phase adjusted output from said first adjustable filter to thereby subtract cross-coupling components from said second signal; first noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said first adder means; second noise-to-signal measuring means for generating a signal proportional to the noise-to-signal ratio in the output signal from said second adder means; and control means for generating signals in accordance with the signals generated by said first and second noise-to-signal measuring means to control said first and second adjustable filters; wherein said first and second adjustable filters each comprise means for varying an input signal by the function W0 [1+W1 ω
+W2 ω
2 +W3 ω
3 ], where ω
is measured from the carrier frequency of the input signal and wherein W0, W1, W2 and W3 are weights controlled by signals from said control means. - View Dependent Claims (27, 28, 29)
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30. An adjustable filter for use in adaptively removing cross-coupling signal components in a channel under the control of an automatic decoupling system comprising:
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first means for generating from an input signal a signal which is constant in magnitude and phase; second means for generating from said input signal a signal with magnitude and phase terms which vary linearly with the frequency ω
across a predetermined frequency bandwidth, the precise linearity variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said automatic decoupling system;third means for generating from said input signal a signal with magnitude and phase terms which vary quadratically with the frequency ω
across said predetermined frequency bandwidth, the precise quadratic variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said automatic decoupling system;fourth means for generating from said input signal a signal with magnitude and phase terms which vary cubically with the frequency ω
across said predetermined frequency bandwidth, the precise cubic variation with frequency of the magnitude and phase of the generated signal being controlled by control signals from said automatic decoupling system; andadder means for combining the output signals from said first, second, third and fourth means for application to the channel to be decoupled. - View Dependent Claims (31, 32, 33)
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34. An adjustable filter for use in adaptively removing cross-coupling signal components in a channel under the control of an automatic decoupling system comprising:
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adder means; means for applying an input signal to said adder means; first linearization means for providing an output signal which varies linearly with the frequency ω
of said input signal and applying this linear output signal to said adder means;second linearization means for providing an output signal which varies linearly with the frequency ω
of the output signal from said first linearization means to thereby provide to said adder means a signal which varies quadratically with the frequency ω
of said input signal; andthird linearization means for providing an output signal which varies linearly with the frequency ω
of the signal from said second linearization means to thereby provide to said adder means a signal which varies cubically with the frequency ω
of said input signal;said adder means adding the output signals from said input applying means, said first linearization means, said second linearization means, and said third linearization means and applying its output to the channel to be decoupled. - View Dependent Claims (35, 36)
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Specification