| 摘要 |
Mixer circuit 300 receives a single-ended rf voltage signal on terminal 330 and a bias potential on terminal 361. Transistor 301 functions as a transconductance amplifier and presents a current signal, representative of the input voltage signal, to mixer core 391. Inductor 310 provides noiseless degeneration in the base-emitter circuit of transistor 301. Local oscillator driver 393 is configured such that its common mode output impedance is higher than the input impedance of transistors 305 and 306. In this way, phase splitting is carried out within the mixer core 391 itself and less transistors are needed. Mixer circuit 300 thereby requires less voltage headroom than prior art mixers.
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