DC offset correction system for a receiver with baseband gain control
First Claim
1. A method in radio frequency (RF) receiver circuitry having a warmup period and a receive path associated therewith and including a baseband analog gain control stage having a gain and a baseband path associated therewith, the method comprising the step of:
- performing, within a feedback loop that includes a digital loop filter, a DC correction calculation operation during the warmup period to derive a DC correction value having a first component and a second component for the baseband analog gain control stage, wherein the step of performing a DC correction calculation operation during the warmup period comprises the steps of;
causing an input to the baseband analog gain control stage to be grounded;
performing a first closed loop correction of the baseband path to derive the first component of the DC correction value, wherein the first component of the DC correction value is a first DC offset value located at an output of the digital loop filter while the input is grounded;
causing the input of the baseband analog gain control stage to be connected to a mixer; and
performing a second closed loop correction of the receive path as a function of the gain during the warmup period to derive the second component of the DC correction value, wherein the second component of the DC correction value is a second DC offset value located at the output of the digital loop filter while the input is connected to the mixer.
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Abstract
A method and apparatus are provided for providing improved radio frequency (RF) receiver signal correction. For RF receiver circuitry (106) having receive path and a warmup period associated therewith and including at least one analog baseband gain control stage (218) having a gain associated therewith, the method includes the step of performing a DC correction calculation operation during the warmup period to derive a DC correction value having a first component and a second component for each of the at least one gain control stage (218). The DC correction calculation step includes the steps of performing a first closed loop correction (460) of a baseband path to derive the first component of the DC correction value and performing a second closed loop correction (462) of the receive path as a function of the (218) gain during the warmup period to derive the second component of the DC correction value. During operation after the warmup period (464 , 466), an open loop correction is performed for instantaneous DC correction as function of the PMA (218) gain and the DC correction value.
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Citations
17 Claims
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1. A method in radio frequency (RF) receiver circuitry having a warmup period and a receive path associated therewith and including a baseband analog gain control stage having a gain and a baseband path associated therewith, the method comprising the step of:
performing, within a feedback loop that includes a digital loop filter, a DC correction calculation operation during the warmup period to derive a DC correction value having a first component and a second component for the baseband analog gain control stage, wherein the step of performing a DC correction calculation operation during the warmup period comprises the steps of; causing an input to the baseband analog gain control stage to be grounded; performing a first closed loop correction of the baseband path to derive the first component of the DC correction value, wherein the first component of the DC correction value is a first DC offset value located at an output of the digital loop filter while the input is grounded; causing the input of the baseband analog gain control stage to be connected to a mixer; and performing a second closed loop correction of the receive path as a function of the gain during the warmup period to derive the second component of the DC correction value, wherein the second component of the DC correction value is a second DC offset value located at the output of the digital loop filter while the input is connected to the mixer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. Radio frequency (RF) receiver circuitry having a warmup period associated therewith, the RF receiver circuitry comprising:
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a baseband analog gain control stage having a gain associated therewith, the baseband analog gain control stage having a first input for receiving a control signal to control the gain thereof, the baseband analog gain control stage further having a second input and an output; automatic gain control circuitry coupled to the baseband analog gain control stage for generating and providing the control signal thereto; a lowband oscillator (LO); a mixer having an input coupled to the LO and an output coupleable to the baseband analog gain control stage; and DC offset correction circuitry that includes a digital loop filter, and that is coupled to the baseband analog gain control stage for receiving information therefrom and coupled to the baseband analog gain control stage and the mixer for control thereof during the warmup period, wherein during the warmup period the DC offset correction circuitry couples the second input of the baseband analog gain control stage to ground to perform a first closed loop correction to derive a first component of a DC correction value, wherein the first component of the DC correction value is a first DC offset value located at an output of the digital loop filter while the second input is grounded, the first component of the DC correction value being stored in the DC offset correction circuitry and couples the second input of the baseband analog gain control stage to the mixer to perform a second closed loop correction as a function of the gain to derive a second component of the DC correction value, wherein the second component of the DC correction value is a second DC offset value located at the output of the digital loop filter while the input is connected to the mixer. - View Dependent Claims (14, 15, 16, 17)
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Specification