High Speed Frequency Hopping Using Injection Locked Front-Ends

Direct digital synthesis (DDS) systems allow for the generation of accurate and versatile analog waveforms. However, DDS's have been limited in generating very high frequency signals. In this paper, we show that a combination of a DDS and harmonic injection locking can result in a very low power and area-efficient high-frequency synthesizer. We show that injection locked oscillators (ILOs) are capable of almost instantaneous locking and we also present the related understanding related of the frequency acquisition process in ILOs. We use this understanding to develop a new architecture for DDS operation. The novel architecture presented in this paper preserves the advantages of DDS such as very high speed frequency hopping and can generate RF frequencies which is not possible with traditional DDS circuits. Simulation results for a 7 GHz oscillator with fundamental and harmonic injection locking are used to validate the instantaneous locking necessary in a high frequency DDS.