Motorola Corporation

Vc Prakash Vk Chacko

Siew Yin Lee

Chow Loong Cheah

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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Gelugor, Malaysia

Vc Prakash Vk Chacko