Methods and apparatus for calibration of automatic gain control in broadcast tuners
First Claim
1. A calibration component configured to calibrate an automatic gain controller (AGC) of a tuner configured to isolate a selected channel from a multi-channel broadcast signal, the tuner implemented substantially on two chips, the calibration component comprising:
- a calibration signal generator implemented on a radio frequency (RF) integrated circuit on a first chip, the RF integrated circuit being adapted for RF channel selection processing of the broadcast signal, the calibration signal generator adapted to generate a generally known calibration signal;
a power detector implemented on the RF integrated circuit and configured to detect, during calibration, at least one power characteristic of the calibration signal and to provide a power level signal indicative of the at least one detected power characteristic;
a gain controller implemented on a digital integrated circuit on a second chip, the digital integrated circuit being adapted for digital channel selection processing of the broadcast signal, the gain controller adapted to generate at least one error signal based, at least in part, on a comparison between the power level signal provided by the power detector and a first reference signal;
an offset signal generator implemented on the RF integrated circuit and configured to generate an offset signal based, at least in part, on the at least one error signal; and
a summing element implemented on the RF integrated circuit and adapted to combine the offset signal with the power level signal provided by the power detector to provide an adjusted power level signal.
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Accused Products
Abstract
In one aspect, a calibration component configured to calibrate an automatic gain controller (AGC) for use in a tuner configured to isolate a selected channel from a multi-channel broadcast signal, the tuner implemented substantially on two chips, a first chip comprising a radio frequency (RF) integrated circuit adapted for RF processing and a second chip comprising a digital integrated circuit adapted for digital processing is provided. The calibration component comprises a calibration signal generator implemented on the RF integrated circuit, the calibration signal generator adapted to generate a generally known calibration signal, a power detector implemented on the RF integrated circuit and configured to detect, during calibration, at least one power characteristic of the calibration signal and to provide a power level signal indicative of the at least one detected power characteristic, a gain controller implemented on the digital integrated circuit, the gain controller adapted to generate at least one error signal based, at least in part, on a comparison between the power level signal provided by the power detector and a first reference signal, an offset signal generator implemented on the RF integrated circuit and configured to generate an offset signal based, at least in part, on the at least one error signal and a summing element implemented on the RF integrated circuit and adapted to combine the offset signal with the power level signal provided by the power detector to provide an adjusted power level signal.
11 Citations
37 Claims
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1. A calibration component configured to calibrate an automatic gain controller (AGC) of a tuner configured to isolate a selected channel from a multi-channel broadcast signal, the tuner implemented substantially on two chips, the calibration component comprising:
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a calibration signal generator implemented on a radio frequency (RF) integrated circuit on a first chip, the RF integrated circuit being adapted for RF channel selection processing of the broadcast signal, the calibration signal generator adapted to generate a generally known calibration signal; a power detector implemented on the RF integrated circuit and configured to detect, during calibration, at least one power characteristic of the calibration signal and to provide a power level signal indicative of the at least one detected power characteristic; a gain controller implemented on a digital integrated circuit on a second chip, the digital integrated circuit being adapted for digital channel selection processing of the broadcast signal, the gain controller adapted to generate at least one error signal based, at least in part, on a comparison between the power level signal provided by the power detector and a first reference signal; an offset signal generator implemented on the RF integrated circuit and configured to generate an offset signal based, at least in part, on the at least one error signal; and a summing element implemented on the RF integrated circuit and adapted to combine the offset signal with the power level signal provided by the power detector to provide an adjusted power level signal. - 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 automatic gain controller (AGC) for use in a tuner adapted to isolate a selected channel from a multi-channel broadcast signal, the AGC configured to operate in a calibration mode adapted to calibrate the AGC, and an operation mode adapted to apply a variable gain to a broadcast signal, the AGC comprising:
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a first control loop comprising; a calibration signal generator adapted to generate a calibration signal; a power detector configured to detect at least one power characteristic of a received input signal and to provide a power level signal indicative of the at least one detected power characteristic; a summing element to combine the power level signal with an offset signal to provide an adjusted power level signal; a gain controller including a reference signal, the gain controller adapted to generate at least one error signal indicative of a difference between the reference signal and the adjusted power level signal; and an offset signal generator adapted to provide the offset signal to the summing element, the offset signal generator configured to adjust the offset signal during the calibration mode based, at least in part, on the at least one error signal; and a second control loop comprising; a variable gain amplifier (VGA) adapted to receive the broadcast signal and to apply a variable gain to the broadcast signal based on a gain signal to provide an amplified broadcast signal; the power detector; the summing element; and the gain controller, wherein, in the calibration mode, the first control loop is operational and the received input signal to the power detector is the calibration signal, the first control loop operating to modify the offset signal such that it reflects an offset error of the AGC, and wherein, in the operation mode, the second control loop is operational and the received input signal to the power detector is the amplified broadcast signal, the second control loop operating to maintain a power level of the amplified broadcast signal within a desired range. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of calibrating an automatic gain controller (AGC) for use in a tuner configured to isolate a selected channel from a multi-channel broadcast signal, the tuner implemented substantially on two chips, the method comprising:
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generating a generally known calibration signal on a radio frequency (RF) integrated circuit on a first chip, the RF integrated circuit being adapted for RF channel selection processing of the broadcast signal; detecting, on the RF integrated circuit, at least one power characteristic of the calibration signal; providing, on the RF integrated circuit, a first power level signal indicative of the at least one power characteristic of the calibration signal; receiving the first power level signal on a digital integrated circuit on a second chip, the digital integrated circuit being adapted for digital channel selection processing of the broadcast signal; generating, on the digital integrated circuit, a first error signal based, at least in part, on a comparison between the first power level signal and a first reference signal; generating an offset signal based, at least in part, on the first error signal; and combining the offset signal with the first power level signal provided by the power detector to provide an adjusted first power level signal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification