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US 6,289,048 B1Granted
Apparatus and method for improving dynamic range in a receiver
AssigneeCubic Communications, Inc.
InventorsWayne E. Richards, Richard Newell Jekel
Life of this patent
Estimating the term…
Abstract
Phase errors and gain errors are reduced in a receiver to increase the dynamic range of the receiver. An input signal is shifted to an intermediate frequency (IF) and divided into a first channel and a second channel. The first and second channels are multiplied by a complex intermediate frequency signal having a frequency equal to the negative of the IF and by the complex conjugate of the intermediate frequency signal to produce a complex normal signal and a complex conjugate signal. A gain correction factor and a phase correction factor are adjusted based on a correlation signal produced by multiplying the complex normal signal by the complex correlation signal.
Claims29
A method of receiving a signal comprising the steps of:
- shifting an incoming signal to an intermediate frequency;
- dividing the signal into a complex signal having positive frequency components and negative frequency components, the complex signal comprising a first channel and a second channel;
- adjusting a phase of the first channel by subtracting a scaled version of the second channel from the first channel, the scaled version derived from a correlation between the positive frequency components and the negative frequency components, and
- adjusting an amplitude of the second channel by a gain correction factor to minimize a gain mismatch between the first channel and the second channel, the gain correction factor based on the correlation between the positive frequency components and the negative frequency components.
1 more element
A method of receiving a signal comprising the steps of:
- frequency shifting the signal to an intermediate frequency;
- dividing the signal into a first channel and a second channel;
- multiplying the second channel by a phase correction factor to produce a correction signal;
- multiplying the second channel by a gain correction factor to produce a corrected second channel;
- combining the first channel with the correction signal to produce a corrected first channel, the corrected second channel and the corrected first channel forming a complex corrected signal;
- multiplying the complex corrected signal by a complex intermediate frequency signal having a frequency equal to a negative of the intermediate frequency to produce a complex normal signal;
- multiplying the complex corrected signal by a complex conjugate of the complex intermediate frequency signal to produce a complex conjugate signal;
- adjusting the phase correction factor to minimize imaginary components of a correlation between the complex normal signal and the complex conjugate signal, and
- adjusting the gain correction factor to minimize real components of the correlation between the complex normal signal and the complex conjugate signal.
6 more elements
A method of receiving a signal comprising the steps of:
- frequency shifting the signal to an intermediate frequency;
- dividing the signal into an in-phase channel (I channel) and a quadrature channel (Q channel);
- multiplying the Q channel by a gain correction factor to produce a corrected Q channel;
- combining the I channel with a phase corrected signal to produce a corrected I channel, the corrected Q channel and the corrected I channel forming a complex corrected signal having positive and negative frequency components;
- multiplying the complex corrected signal by a complex intermediate frequency signal having a frequency equal to a negative of the intermediate frequency to produce a complex normal signal;
- multiplying the complex corrected signal by a complex conjugate of the complex intermediate frequency signal to produce a complex conjugate signal;
- and
- adjusting the gain correction factor to minimize a correlation between the complex normal signal and the complex conjugate signal.
5 more elements
A method of receiving a signal comprising the steps of:
- frequency shifting the signal to an intermediate frequency;
- dividing the signal into an in-phase channel (I channel) and a quadrature channel (Q channel);
- multiplying the Q channel by a phase correction factor to produce a correction signal;
- combining the I channel with the correction signal to produce a corrected I channel;
- multiplying the Q channel by a gain correction factor to produce a corrected Q channel, the corrected Q channel and the corrected I channel forming a complex corrected signal;
- multiplying the complex corrected signal by a complex intermediate frequency signal having a frequency equal to a negative of the intermediate frequency to produce a complex normal signal;
- multiplying the complex corrected signal by a complex conjugate of the complex intermediate frequency signal to produce a complex conjugate signal;
- multiplying the complex normal signal by the complex conjugate signal to produce a complex correlation signal;
- adjusting the phase correction factor to minimize an imaginary component of the complex correlation signal;
- and
- adjusting the gain correction factor to minimize a real component of the complex correlation signal.
8 more elements
A receiver comprising:
- a frequency shifter adapted to shift a signal to an intermediate frequency;
- a signal divider adapted to divide the signal into a first channel and a second channel;
- a signal combiner adapted to combine a scaled version of the second channel to the first channel to produce a corrected first channel;
- a correlation controller adapted to determine a gain correction factor for adjusting the second channel, and a phase correction factor for producing the scaled version of the second channel, the correlation controller comprising:
- a first complex multiplier adapted to produce a complex normal signal by multiplying the corrected first channel and the adjusted second channel by a complex intermediate frequency signal having a frequency equal to a negative of the intermediate frequency;
- a second complex multiplier adapted to produce a complex conjugate signal by multiplying the corrected first channel and the adjusted second channel by a complex conjugate of the complex intermediate frequency signal;
- and
- a correlator adapted to correlate the complex normal signal and the complex conjugate signal to produce a correlation signal having a real component and an imaginary component, wherein the phase correction factor is based on the imaginary component of the correlation signal, and wherein the gain correction factor is based on the real component of the correlation signal.
5 more elements
A receiver comprising:
- a quadrature divider adapted to divide an input signal into an in-phase (I) channel at an intermediate frequency and a quadrature (Q) channel at the intermediate frequency;
- a phase correction multiplier adapted to scale the Q channel to produce a scaled version of the Q channel by multiplying the Q channel by a phase correction factor;
- a signal combiner adapted to combine the scaled version of the Q channel to the I channel to produce a corrected I channel;
- a gain correction multiplier adapted to scale the Q channel to produce a corrected Q channel by multiplying the Q channel by a gain correction factor, the corrected I channel and the corrected Q channel forming a corrected complex channel;
- a first complex multiplier adapted to produce a complex normal signal by multiplying the corrected complex channel by a complex intermediate frequency signal having a frequency equal to a negative of the intermediate frequency;
- a second complex multiplier adapted to produce a complex conjugate signal by multiplying the corrected complex channel by a complex conjugate of the complex intermediate frequency signal;
- a third complex multiplier adapted to correlate the complex normal signal and the complex conjugate signal to produce a correlation signal by multiplying the complex normal signal by the complex conjugate signal;
- and
- a correction circuit coupled to the third complex multiplier, the correction circuit adapted to producing the phase correction factor and the gain correction factor based on the correlation signal.
6 more elements
A correction controller for determining a phase correction factor and a gain correction factor for correcting phase and gain errors between an in-phase (I) channel and a quadrature (Q) channel of an input signal, the correction controller comprising:
- a pair of complex multipliers adapted to multiply the I channel and the Q channel by an intermediate frequency and a conjugate of the intermediate frequency signal to produce a complex normal signal and a complex conjugate signal;
- a correlator coupled to the pair of complex multipliers and adapted to produce a correlation signal based on a correlation between the complex normal signal and the complex conjugate signal;
- and
- a correction circuit adapted to produce the phase correction factor and the gain correction factor based on the correction signal.
1 more element
Dependencies are inferred from the claim text.