| 摘要 |
An embodiment of a variable-gain mixer for down-converting a modulated input signal into a modulated output signal in a wireless receiver is proposed. The mixer includes means for selecting a mixer gain according to a power level of the input signal, amplifying means for amplifying the input signal into a modulated intermediate current (IRF+,IRF-) in response to a control signal indicative of the selected mixer gain, the intermediate current having an intermediate component, consisting of a direct current, varying according to the selected mixer gain, means for generating the output signal from the intermediate current, the output signal having an output component, consisting of a direct current or voltage, depending on the intermediate component; in an embodiment, the mixer further includes means for setting a compensation current in response to the control signal for compensating the variation of the intermediate component, and means for adding the compensation current to the intermediate current. |
