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 Title: |
US6560449:
Image-rejection I/Q demodulators
[ Derwent Title ]
>> View Certificate of Correction for this publication
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| Country: |
US United States of America
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| Inventor: |
Liu, Bin; Danville, CA
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| Assignee: |
Broadcom Corporation, Irvine, CA
other patents from BROADCOM CORPORATION (728124) (approx. 518)
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| Published / Filed: |
2003-05-06
/ 2000-06-12
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| Application Number: |
US2000000591925
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| IPC Code: |
Advanced:
H04L 27/00;
Core:
more...
IPC-7:
H04B 1/10;
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| ECLA Code: |
H04L27/00R;
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| U.S. Class: |
455/302;
455/205;
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| Field of Search: |
455/302,304,308,309,310,312,326,334,337,147,205,208,210
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| Priority Number: |
| 2000-06-12 |
US2000000591925 |
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| Abstract: |
In a communications receiver for quadrature demodulation, a feedback technique for reducing the image response of the receiver. The communications receiver includes an I demodulator and a Q demodulator. A local oscillator (LO) signal is provided by a PLL to a quadrature LO generator that provides an LO_I signal to an I demodulator and an LO_Q signal to a Q demodulator. The LO_I and LO_Q signals are amplitude and phase-controlled versions of the LO signal. An image/signal ratio (I/S) detector detects the relative phase difference and the relative amplitude difference between the respective output terminals of the I demodulator and the Q demodulator and applies an amplitude control signal and a phase control signal to corresponding amplitude control and phase control inputs of the quadrature LO generator. The I/S detector calibrates the quadrature LO generator during the interstitial interval between the reception of data packets. The control signals from the I/S detector adjust the relative amplitude and phase of the LO_I and LO_Q signals in a manner that reduces the image response of the communications receiver.
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| Attorney, Agent or Firm: |
Christie, Parker & Hale, LLP ;
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| Primary / Asst. Examiners: |
Hunter, Daniel; Nguyen, Thuan T.
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| Maintenance Status: |
CC Certificate of Correction issued
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| INPADOC Legal Status: |
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Family Legal Status Report
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| Designated Country: |
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
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| Family: |
Show 8 known family members
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First Claim:
Show all 36 claims |
What is claimed is:
1. A communications receiver comprising:
- a carrier signal source;
- a first demodulator having a first input terminal coupled to an output terminal of the carrier signal source;
- a second demodulator having a first input terminal coupled to an output terminal of the carrier signal source;
- a local oscillator (LO) signal source;
- a quadrature phase shifter having an LO input terminal coupled to the LO signal source, an in-phase (I) output terminal coupled to a second input terminal of the first demodulator, and a quadrature (Q) output terminal coupled to a second input terminal of the second demodulator; and
- an image/signal ratio detector having a first input terminal coupled to an output terminal of the first demodulator, a second input terminal coupled to an output terminal of the second demodulator, and an output terminal coupled to the quadrature phase shifter for adjusting the I output of the phase shifter and the Q output of the phase shifter thereby to adjust the image response of the communications receiver.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 36 U.S. patent(s) that reference this one
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