초록 ▼

The present invention provides a method and apparatus for detecting and compensating for transmitter phase shift in a radio transmitter. A local oscillator generates a local oscillator signal. A modulator such as an I/Q modulator modulates input signals onto the local oscillator signal to generate a

The present invention provides a method and apparatus for detecting and compensating for transmitter phase shift in a radio transmitter. A local oscillator generates a local oscillator signal. A modulator such as an I/Q modulator modulates input signals onto the local oscillator signal to generate a forward signal. That forward signal is amplified and otherwise prepared for transmission via an antenna. The transmitted signal is detected, and a phase adjuster substantially continuously detects and cancels undesired phase shifts in the detected signal caused by elements in the radio chain. A specific, example embodiment of the present invention is provided in a Cartesian feedback system wherein the phase of the feedback signal is detected and aligned with the phase of the original modulated signal, providing uncorrupted I and Q baseband feedback signals.

대표청구항 ▼

[ What is claimed is:] [1.] Apparatus comprising:a local oscillator for generating a local oscillator signal;first and second combiners receiving an in-phase signal and a quadrature signal, respectively;a first quadrature modulator modulating in-phase and quadrature signals received from the first a

[ What is claimed is:] [1.] Apparatus comprising:a local oscillator for generating a local oscillator signal;first and second combiners receiving an in-phase signal and a quadrature signal, respectively;a first quadrature modulator modulating in-phase and quadrature signals received from the first and second combiners onto the local oscillator signal to generate a forward signal;a power amplifier receiving and amplifying the forward signal;an antenna for transmitting the amplified signal;a detector detecting the transmitted signal and producing a detected signal;a phase adjuster, receiving signal produced by the local oscillator and the detector, adjusting the phase of the local oscillator signal to that of the detected signal; anda first quadrature demodulator, coupled to the phase adjuster and the detector, demodulating the detected signal in accordance with the adjusted local oscillator signal to generate feedback in-phase and quadrature signals that are combined in the first and second combiners, respectively,wherein the phase adjuster includes:a second quadrature demodulator having the forward signal connected to one input port and the detected signal connected to a second input port and generating second in-phase and quadrature signals;first and second detectors for processing the second in-phase and quadrature signals, respectively; anda second quadrature modulator, connected to the local oscillator, for receiving output signals from the first and second detectors and generating the phase adjusted local oscillator signal.