Pulse or digital communications – Receivers – Automatic frequency control
Reexamination Certificate
2007-01-10
2010-12-28
Payne, David C (Department: 2611)
Pulse or digital communications
Receivers
Automatic frequency control
C455S075000
Reexamination Certificate
active
07860196
ABSTRACT:
A method and circuit are described for estimating I and Q amplitude imbalance occurring in a signal received by a direct conversion receiver (DCR). The DCR generates a mixing signal having a frequency substantially the same as the carrier signal of the signal received by an antenna. A mixing module mixes the mixing signal at different phases with the received signal to generate I and Q baseband signals. A frequency offset circuit generates an offset signal having a frequency offset from the carrier signal frequency. A coupling circuit selectively decouples the antenna from the DCR and couples the offset signal to the mixing module to generate a baseband test signal in the I and Q signal paths for determining an imbalance in the amplitudes of the baseband test signals between the I and Q signal paths.
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patent: 5584062 (1996-12-01), Meador et al.
patent: 2003/0202571 (2003-10-01), Kearney
patent: 2004/0106380 (2004-06-01), Vassiliou et al.
patent: 1020040036492 (2004-04-01), None
Chacko Vc Prakash Vk
Cheah Chow Loong
Lee Siew Yin
Curtis Anthony P.
Hughes Terri S.
Motorola Inc.
Payne David C
Stevens Brian J
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