| 摘要 |
Mixer circuit 400 receives a differential input voltage signal on terminals 440, 441. The input voltage signal is converted into a differential current signal by current conveyors 420, 421, the circuits of which are shown in Figures 2 and 3. Current conveyors 420, 421 each operate to hold the voltage at current input X equal to the voltage present on voltage input Y. By virtue of resistors 411, 413, the Y terminals of current conveyors 420, 421 each receive the common mode voltage of the input signal. This causes the current signal at the X terminals to have a zero bias and to vary linearly with the input voltage. The current output from Z is dependent on the input current at X. Thus mixer core 430 receives differential current signals representative of the input voltage signal. Because the voltage at the Z terminals of current conveyors 420, 421 is independent of the input voltage, this circuit is particularly useful in low voltage applications. Current conveyors 420, 421 may include bipolar or field effect transistors.
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