| 摘要 |
A mixer circuit (400) for use with a multi-stage receiver (200) accepts a single ended or differential (i.e. balanced) input (401). A voltage to current converter (402) comprised of a single RF transistor coupled to the input (401) provides a single current node (404) having a current proportional to a received input. A switching network (408) employs a plurality of stages (406). Each stage (406) is connected to the current node (404) and further has a control line (A, B, C, D). A clock signal generator connected to the control lines (A, B, C, D) of the switching network stage (406), generates clock signals having a frequency equal to the frequency of the received RF input signal. The switching network (408) under control of the clock signals switches the current at a frequency equal to the frequency of the received RF input signal to generate baseband I and Q signals. If the mixer (500) is differential, the balanced signal inputs (520) will be 180 DEG out of phase, one to another. In addition, the mixer (500) will consist of a first (510) and second (515) switching network. Of importance, only one first (510) and one second (515) switching network stage is active at any instant in time.
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