Understanding Mixers From a Switching Perspective

Download Whitepaper
  • Author: Gary Breed
Mixers are impor-tant components for frequency conversion, signal detec-tion and phase detection. Often, it is the perfor-mance of the mixer that establishes limits for the overall noise figure or intercept point of a com-munication system. This tutorial offers a review of mixers from a specific perspective—switching (also referred to as commutation). This a good time to review these circuits. Digital signal processing has shortened the RF/microwave path between front end and baseband in today’s receivers. Sometimes, that path includes little more than a bandpass fil-ter followed by two mixer/detectors that deliv-er I and Q signals to the baseband processor. Without the usual IF filter to provide addi-tional selectivity, the performance of the mixer has an even greater effect on the receiver’s ability to reject unwanted signals.