Defining, Selecting or Designing the Right LO System for Frequency Converters

Frequency converters are rapidly becoming the only analog building block in a variety of RF and Microwave systems. The advent of synthetic instruments puts frequency converters at center stage within the RF architecture of test systems. This paper highlights the crucial role the local oscillator (LO) plays in the architecture of frequency converters (up and down). Converter architecture is split between LO system and channel, where the channel is basically the signal path. We show the effect of trade-offs between these two branches on the overall performance and complexity of the converter implementation. Advances in synthesizer technology make it possible to place more burden on the LO system to end up with simpler converter system having adequate performance.