Quadrature voltage controlled oscillators with phase shift detector
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Accused Products
Abstract
In wireless application there is made use of a quadrature oscillators that generate signals that are capable of oscillating at quadrature of each other. The quadrature oscillator is comprised of two differential modified Colpitts oscillators. A capacitor bank allows for the selection of a desired frequency from a plurality of discrete possible frequencies. The quadrature oscillator is further coupled with a phase-error detector connected at the point-of-use of the generated ‘I’ and ‘Q’ channels and through the control of current sources provides corrections means to ensure that the phase shift at the point-of-use remains at the desired ninety degrees.
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Citations
18 Claims
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1-8. -8. (canceled)
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9. A phase error detector (PED) for detecting a phase error in a quadrature signal, said PED comprising:
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a first analog OR gate having an input for receiving a positive in-phase (‘
I’
) signal and a positive quadrature-phase (‘
Q’
) signal;
a second analog OR gate having an input for receiving a negative ‘
I’
signal and a negative ‘
Q’
signal;
first circuitry for summing the output from said first analog OR gate and said second analog OR gate to generate a first circuitry output;
a third analog OR gate having an input for receiving a positive ‘
I’
signal and a negative ‘
Q’
signal;
a fourth analog OR gate having a first input for receiving a negative ‘
I’
signal and a positive ‘
Q’
signal; and
,second circuitry for summing the output from said third analog OR gate and said fourth analog OR gate and there from generating a second circuitry output;
whereby the difference between said first circuitry output and said second circuitry output is a signal proportional to a phase error between the ‘
I’
signal and the ‘
Q’
signal of the quadrature signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for detecting a phase error in a quadrature signal comprising:
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providing a first analog OR gate with a positive in-phase (‘
I’
) signal and a positive quadrature-phase (‘
Q’
) signal;
providing a second analog OR gate with a negative ‘
I’
signal and a negative ‘
Q’
signal;
summing the output from said first analog OR gate and the output of said second analog OR gate to generate a first circuitry output;
providing a third analog OR gate with a positive ‘
I’
signal and a negative ‘
Q’
signal;
providing a fourth analog OR gate with negative ‘
I’
signal and a positive ‘
Q’
signal;
summing the output from said third analog OR gate and said fourth analog OR gate to generate a second circuitry output; and
,using the difference between said first circuitry output and said second circuitry output to determine the phase error between the ‘
I’
signal and the ‘
Q’
signal of the quadrature signal. - View Dependent Claims (18)
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Specification