Frequency-Domain Analysis of Super-Regenerative Amplifiers

Abstract

Since its invention in 1922, the super-regenerative amplifier (SRA) has been used in a variety of short-range, low-power, and/or low-cost wireless systems due to its simple implementation and excellent performance for a given power budget. Growing demand for ultralow-power receivers for short-range radios has recently reawakened an interest in the theory and design of SRAs. Building on recent work and using reasonable assumptions and approximations, we present a frequency-domain model for analyzing SRAs. We then use these models to predict the response of an SRA to arbitrary deterministic and stochastic signals including sinusoids, pulsed-sinusoids, and additive white Gaussian noise. Using the results, we present formulas for calculating the sensitivity and selectivity of SRAs. We also introduce the concept of a trigger-time that is particularly useful for accurately determining the optimal threshold in on-off keying (OOK) receivers and helps avoid the problems introduced by nonlinearity in SRAs. Finally, we present a prototype OOK SRA that achieves a sensitivity of 90 dBm at a bit rate of 300 kbps (BER of 10 3 ) while consuming 500 W, and show that its measured sensitivity matches theory within 1 dB.Index Terms-Super-regenerative amplifier (SRA), super-regenerative receiver, low power, oscillators, short-range radio.

A Superregenerative QPSK Receiver

“…So, in response to the quench pulses, the SRO is able to generate RF pulses. Several parameters of these RF pulses are dependent on the value of certain parameters (amplitude, phase, frequency) of the external RF input signal in a sensitivity window centered around the instants where the system changes from stable to unstable [10], [11]. Copyright (c) 2013 IEEE.…”

A high-sensitivity 135GHz millimeter-wave imager by compact split-ring-resonator in 65-nm CMOS

“…As discussed in [14], for a typical ramp-damping function with a normalized ramping slope of k, we have…”

A 2.7 GHz super-regenerative receiver front-end for QPSK modulated signals

“…Mathematical analyses, either in time domain, [8] or frequency domain, [9] show that the output phase of super-regenerative oscillator captures the phase of the RF input at the start of oscillation (i.e. when SRO is quenched to oscillate), especially if the input frequency is equal to the oscillator natural frequency.…”

“…Quench current is the oscillator bias current, quench signal shape has a direct impact on SRO properties, it was shown in [9] that ramp quench current results in better performance in terms of selectivity and gain with respect to sinusoidal quench current, where the selectivity of ramp quenched SRO is controlled by ramp slope.…”