Feedback Compensation Detector For A Direct Conversion Transmitter
First Claim
1. A direct up conversion transmitter chain, comprising:
- means for generating an in-phase (I) baseband signal and a quadrature-phase (Q) baseband signal;
means for combining the I and Q baseband signals with a radio frequency (RF) carrier signal to generate an RF output signal;
means for transmitting the RF output signal;
pre-distortion means for down-converting the RF output signal to generate an intermediate frequency (IF) signal, measuring at least one signal impairment in the IF signal, and pre-distorting the I and Q baseband signals to compensate for the measured signal impairment; and
means for generating a reference voltage as a function of both an ambient temperature in the vicinity of the pre-distortion means and a battery supply voltage;
wherein the direct up conversion transmitter chain estimates actual values for the ambient temperature and the battery supply voltage and adjusts the signal impairment by a function of estimated ambient temperature and estimated battery supply voltage.
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Accused Products
Abstract
A feedback compensation detector for a direct conversion transmitter includes a baseband processor, a direct up-converter, an antenna, and an impairment detection and compensation feedback circuit. The baseband processor generates an in-phase (I) baseband signal and a quadrature-phase (Q) baseband signal. The direct up-converter is coupled to the baseband processor, and combines the I and Q baseband signals with an RF carrier signal to generate an RF output signal. The antenna is coupled to the direct up-converter, and transmits the RF output signal. The impairment detection and compensation feedback circuit is coupled to the RF output signal and the I and Q baseband signals. The impairment detection and compensation feedback circuit down-converts the RF output signal to generate an intermediate frequency (IF) signal, measures as least one signal impairment in the IF signal, and pre-distorts the I and Q baseband signals to compensate for the measured signal impairment.
73 Citations
44 Claims
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1. A direct up conversion transmitter chain, comprising:
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means for generating an in-phase (I) baseband signal and a quadrature-phase (Q) baseband signal; means for combining the I and Q baseband signals with a radio frequency (RF) carrier signal to generate an RF output signal; means for transmitting the RF output signal; pre-distortion means for down-converting the RF output signal to generate an intermediate frequency (IF) signal, measuring at least one signal impairment in the IF signal, and pre-distorting the I and Q baseband signals to compensate for the measured signal impairment; and means for generating a reference voltage as a function of both an ambient temperature in the vicinity of the pre-distortion means and a battery supply voltage; wherein the direct up conversion transmitter chain estimates actual values for the ambient temperature and the battery supply voltage and adjusts the signal impairment by a function of estimated ambient temperature and estimated battery supply voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A direct up conversion transmitter chain, comprising:
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means for generating an in-phase (I) baseband signal and a quadrature-phase (Q) baseband signal; pre-distortion means coupled to a feedback signal for pre-distorting the I and Q baseband signals as a function of at least one signal impairment parameter in the feedback signal and generating modified I and Q baseband signals; means for combining the modified I and Q baseband signals with a radio frequency (RF) carrier signal to generate an RF output signal; means for transmitting the RF output signal; impairment detection means for down-converting the RF output signal to generate an intermediate frequency (IF) signal, estimating the signal impairment parameter from the IF signal, and generating the feedback signal, including temperature and voltage sensitive components; means for generating a temperature sensor voltage as a function of both an ambient temperature in the vicinity of the impairment detection means and a battery supply voltage; means for estimating the signal impairment parameter from the IF signal and adjusting the signal impairment parameter by a function of the temperature sensor voltage; and means for generating a reference voltage as a function of both the ambient temperature in the vicinity of the impairment detection means and the battery supply voltage; wherein the means for estimating estimates actual values for the ambient temperature and the battery supply voltage and adjusts the signal impairment by a function of the estimated ambient temperature and the estimated battery supply voltage. - View Dependent Claims (23)
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24. A direct up conversion transmitter chain, comprising:
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a baseband processor that generates a baseband signal; a direct up-converter that combines the baseband signal with a radio frequency (RF) carrier signal to generate an RF output signal; an antenna that transmits the RF output signal; an impairment detection and compensation feedback circuit that down-converts the RF output signal to generate an intermediate frequency (IF) signal, measures at least one signal impairment in the IF signal, and pre-distorts the baseband signal to compensate for the measured signal impairment; a band gap voltage reference that generates a reference voltage as a function of both an ambient temperature in the vicinity of the impairment detection and compensation feedback circuit and a battery supply voltage; wherein the direct up conversion transmitter chain estimates actual values for the ambient temperature and the battery supply voltage and adjusts the signal impairment by a function of the estimated ambient temperature and the estimated battery supply voltage. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification