Direct conversion receiver

Details Direct conversion receiver Direct conversion receiver

2007-03-20

2010-12-21

Vo, Nguyen (Department: 2618)

Telecommunications

Receiver or analog modulated signal frequency converter

Local control of receiver operation

C455S312000, C455S324000

Reexamination Certificate

active

07856218

ABSTRACT:
In a direct conversion receiver, to cancel a DC offset generated in the baseband processing block, negative feedback arrangements comprising a gain control amplifier and a low-pass filter are respectively attached to the I and Q signal branches of the baseband block following mixer outputs. The gain control amplifier in each negative feedback circuit is gain adjusted so that the product G·B of the gain G of a primary gain control amplifier and its own gain B will be constant and thereby the DC offset is cancelled. This DC offset cancellation can be applied in a continuous receiving system with no intermittent time during a receiving operation. Capacitance elements located off-chip can be reduced to those to be used only in the low-pass filters in the negative feedback circuits, whereas many off-chip capacitance elements have been required to be inserted between each stage of gain control amplifiers in conventional baseband chains.

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Japanese Office Action dated Dec. 18, 2007, in Japanese and English.

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