Frequency Domain Analysis of Superregenerative Receivers in the Linear and the Logarithmic Modes

Despite their simplicity, analysis and design of superregenerative oscillators is often still based on approximations which provide limited insight into its behavior. In this paper we investigate the superregenerative oscillator in the linear and logarithmic operation modes without any approximations. A frequency-domain formulation allows us to efficiently compute the relevant waveforms both in the time and in the frequency domains. One of the main results is the ability to efficiently predict the exact envelope and the instantaneous phase and frequency of the generated waveforms for sinusoidal input signals. The formulation allows taking into account different amplitude-limiting nonlinearities that are responsible for the logarithmic response. We analyze different superregenerative oscillator designs under various operating conditions. We also provide a comparison of the results with those obtained with other techniques.