A Superregenerative QPSK Receiver

Abstract

Abstract-In this paper we present a description and experimental verification of a superregenerative receiver (SR) for QPSK signals. Exploiting the fact that a conventional SR generates pulses which preserve the input phase information, we take N 1-bit samples of each generated pulse. A suitable choice of the sampling frequency gives as a result a bit vector containing a sub-sampled version of each PSK pulse. Extremely simple digital processing of the vectors from two consecutive pulses allows symbol decision, together with information on signal quality and frequency displacements. Although presented for the QPSK case, the principle may be applied to the M-PSK case with obvious changes. Experimental results on a 20 kbit/s proof-of concept receiver in the 27 MHz band, achieving a sensitivity of −103 dBm, with an FPGA-based implementation of the digital part, validate the proposed approach.

Envelope-Domain Analysis and Modeling of Super-Regenerative Oscillators

“…15(b) compares the phase of the input and output signals. In agreement with the derivations in [5], the SRO is able to follow the phase shifts. Fig.…”

“…UPER-REGENERATIVE OSCILLATORS (SROs), which are periodically switched on and off by a quench signal [1]- [5], enable a high gain amplification of a small input signal near the oscillator resonant frequency. This amplification is due to the fast amplitude growth during each oscillation start-up cycle [1]- [5], which is exponential in its initial stage.…”

“…UPER-REGENERATIVE OSCILLATORS (SROs), which are periodically switched on and off by a quench signal [1]- [5], enable a high gain amplification of a small input signal near the oscillator resonant frequency. This amplification is due to the fast amplitude growth during each oscillation start-up cycle [1]- [5], which is exponential in its initial stage. SROs have recently attracted significant attention since they can replace chains of several lower gain amplifiers, enabling a reduction of power consumption, which has a special interest at millimeter and Terahertz frequencies [6]- [7].…”

“…The high-gain amplification associated with the superregenerative effect allows for compact transponders with a long-range operation. The works [2], [4]- [5] present a thorough and insightful formulation for the super-regenerative receiver, based on the approximate analytical resolution of the second-order differential equation system that describes the switched oscillator in the presence of a weak input signal. A closed-form expression of the solution [2] is derived, in terms of superregenerative and regenerative gains, sensitivity function and normalized envelope.…”

Analysis of Superregenerative Oscillators in Nonlinear Mode

“…SUPERREGENERATIVE oscillator (SRO), switched on and off by a quench signal, uses the fast growth of the oscillation amplitude during the start-up transient to obtain high gain amplification [1]- [6]. This is achieved with the advantages of a compact size, low consumption and low cost.…”