Fast RF-Synthesizer based on Direct Digital Synthesis for an Instantaneous Frequency Measurement System

This paper presents a fast RF-synthesizer for instantaneous frequency measurement (IFM) based on six-port technology for surface acoustic wave (SAW) resonators in the 2.4 GHz Industrial, Scientific and Medical (ISM) band. The synthesizer is based on direct digital synthesis (DDS), which is a viable alternative to phase locked loops (PLL) due to improved IC technologies, and is able to precisely produce signals to interrogate resonant SAW sensors and perform linearization with several frequencies and amplitude steps.