Method and apparatus for reducing DC offsets in a communication system
First Claim
1. A feedback loop circuit apparatus for reducing DC offset in a communication channel, comprising:
- a summing node in a receiver channel, wherein a receiver channel signal is coupled as an first input to said summing node; and
an integrator that has an input coupled to a second node of said receiver channel, wherein an output of said integrator is coupled as a second input to said summing node.
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Abstract
Methods and apparatuses for reducing DC offsets in a communication system are described. In a first aspect, a feedback loop circuit reduces DC offset in a wireless local area network (WLAN) receiver channel. The frequency response of the feedback loop circuit can be variable. In a second aspect, a circuit provides gain control in a WLAN receiver channel. First and second automatic gain control (AGC) amplifiers are coupled in respective portions of the receiver channel. Circuits for monitoring DC offset, and for providing control signals for controlling the frequency response of the DC offset reducing circuits are also provided.
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Citations
52 Claims
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1. A feedback loop circuit apparatus for reducing DC offset in a communication channel, comprising:
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a summing node in a receiver channel, wherein a receiver channel signal is coupled as an first input to said summing node; and
an integrator that has an input coupled to a second node of said receiver channel, wherein an output of said integrator is coupled as a second input to said summing node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for gain control in a communication channel, comprising:
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a multiplier that receives a first automatic gain control (AGC) signal and outputs a second AGC signal;
a first AGC amplifier that receives said first AGC signal; and
a second AGC amplifier that receives said second AGC signal. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A method for reducing DC offset in a communication channel, comprising the steps of:
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(1) integrating an output signal available at a first node to generate an integrated signal; and
(2) summing the integrated signal with a receiver channel signal at a second node, wherein the first node is downstream from the second node in a receiver channel. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method for gain control in a communication channel, comprising the steps of:
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(1) multiplying a first automatic gain control (AGC) signal by an amount to generate a second AGC signal;
(2) providing the first AGC signal to a AGC amplifier; and
(3) providing the second AGC signal to a second AGC amplifier. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
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49. A method for reducing DC offset in a communication channel, comprising the steps of:
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(1) measuring a DC offset voltage present in an output signal at a first node; and
(2) removing the measured DC offset voltage from a receiver channel signal at a second node, wherein the first node is downstream from the second node in a receiver channel. - View Dependent Claims (50, 51, 52)
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Specification