| 摘要 |
A polyphase filter having a DC offset cancellation network is disclosed. The polyphase filter includes a first filter section to generate a first set of I- and Q- output signals, a second filter section to generate a second set of I- and Q- output signals, and a DC offset cancellation feedback device to generate four DC offset cancellation signals such that when combined with the input I- and Q- signals, the level of DC offset within the polyphase filter is substantially reduced. Also, a transconductance cell useful for the polyphase filter is disclosed. The transconductance cell includes a first pair of FETs having common gates to receive an input signal and common drains to generate a complementary output signal, a second pair of FETs having common gates to receive a complementary input signal and common drains to generate an output signal, and tail current FET to control the transconductance.
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