Keeping the calls coming
High performance active mixer helps designers juggle rf transmitter design challenges. By James Wong.
The design of next generation cellular basestation transmitters imposes significant challenges for rf engineers. These wireless systems have stringent requirements for the transmission of a clean signal with a low noise floor, along with low intermodulation and harmonic distortion. This is particularly challenging, as higher order modulation is required whilst transmitting multiple carrier signals.
Demand for linear mixer performance is high in such applications. In the past, these requirements have been met using passive diode ring type mixers. Today, a new generation of active mixers offers significant advantages. Not only do these devices save cost, power and space, they also solve some of the most difficult technical problems associated with high performance transmitter designs.
