Page 327 - Complete Wireless Design
P. 327
Mixer Design
326 Chapter Seven
Figure 7.12 One method of using a transistor as a nonlinear mixer stage.
Figure 7.13 A Gilbert cell integrated mixer.
and Q ), while the square wave LO is input into the base of Q . The LO causes
2 3
Q and Q to be on, and next Q and Q transistors are turned on, causing mix-
3 6 4 5
ing of the LO and the RF, creating the IF signal.
Many active mixers can be operated past their maximum rated frequency,
but there will be a conversion loss instead of a conversion gain. Depending on
design, these mixers are also available for both balanced and unbalanced oper-
ation, and can be found in low-cost dual in-line packages.
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