Demodulator for use in wireless communications and receiver, method and terminal using it
First Claim
1. A demodulator for demodulating a frequency modulated RF signal, including an input signal path for delivering an RF input signal, a local oscillator, a first mixer connected to the input signal path for mixing an output reference signal from the local oscillator with an RF input signal to produce an in-phase component of the input received signal, connected to the input signal path a second mixer for mixing a phase-shifted version of the output reference signal from the local oscillator with the RF input signal to produce a quadrature component of the RF input signal;
- and an output digital signal processor for producing an output demodulated information signal by producing a function of the in-phase and quadrature components; and
wherein the demodulator is periodically operable in a quadrature phase error determination mode wherein the reference signal produced by the local oscillator has a frequency which is offset from the carrier frequency of an RF input signal.
1 Assignment
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Accused Products
Abstract
A demodulator (100), includes an input signal path (101) for delivering an RF input signal, a local oscillator (111), connected to the input signal path a first mixer (107) for mixing an output reference signal from the local oscillator with an RF input signal to produce an in-phase component of the input received signal, a phase shifter (113), connected to the input signal path a second mixer (109) for mixing an output reference signal from the local oscillator via the phase shifter with the RF input signal to produce a quadrature component of the RF input signal; and an output signal processor (119) for producing an output demodulated information signal by producing a function of the in-phase and quadrature components; and wherein the demodulator is periodically operable in a quadrature phase error determination mode.
32 Citations
20 Claims
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1. A demodulator for demodulating a frequency modulated RF signal, including an input signal path for delivering an RF input signal, a local oscillator, a first mixer connected to the input signal path for mixing an output reference signal from the local oscillator with an RF input signal to produce an in-phase component of the input received signal, connected to the input signal path a second mixer for mixing a phase-shifted version of the output reference signal from the local oscillator with the RF input signal to produce a quadrature component of the RF input signal;
- and an output digital signal processor for producing an output demodulated information signal by producing a function of the in-phase and quadrature components; and
wherein the demodulator is periodically operable in a quadrature phase error determination mode wherein the reference signal produced by the local oscillator has a frequency which is offset from the carrier frequency of an RF input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17, 18, 19)
- and an output digital signal processor for producing an output demodulated information signal by producing a function of the in-phase and quadrature components; and
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15. (canceled)
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16. A method of estimating a quadrature phase error of an RF demodulator which demodulator includes an input signal path for delivering an RF input signal, a local oscillator, connected to the input signal path a first mixer for mixing an output reference signal from the local oscillator with an RF input signal to produce an in-phase component of the input received signal, connected to the input signal path a second mixer for mixing a phase shifted output reference signal from the local oscillator with the RF input signal to produce a quadrature component of the RF input signal;
- and an output signal processor for producing an output demodulated information signal by producing a function of the in-phase and quadrature components;
the method comprising periodically operating the demodulator in a quadrature phase error determination mode wherein the reference signals produced by the local oscillator of the demodulator have a frequency which is offset from the carrier frequency of an RF input signal.
- and an output signal processor for producing an output demodulated information signal by producing a function of the in-phase and quadrature components;
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20. A mobile station for use in wireless communications incorporating a RF transceiver according to claim 20.
Specification