Super-regenerative Oscillators Research Articles

Two-Band Model of Super-Regenerative Oscillators

Two-Band Model of Super-Regenerative Oscillators

Analysis and Modeling of Super-Regenerative Oscillators With FSCW Signals

Analysis and Modeling of Super-Regenerative Oscillators With FSCW Signals

Nonlinear Analysis of Cross-Coupled Super-Regenerative Oscillators

In this paper, a nonlinear analysis of cross- coupled super-regenerative oscillators (SROs) is presented. The start-up and decay envelopes of the oscillator output are studied in relation to the input. The SRO start-up time and the maximal achievable quenching frequency are investigated. For phase modulation purposes, the relation between the initial phases of the input and output signals is investigated. In addition, a frequency-domain analysis is performed to ease the characterization of circuit prototypes at frequencies where time-domain measurements are not possible. The analytical results are verified by circuit-level simulations and measurements of a 2.4-GHz SRO. This study provides design guidelines for the design of SROs in cross-coupled architectures and helps in determining the optimal system parameters when targeting both amplitude and phase modulations. To the authors' best knowledge, this is the first study investigating analytically the phase relation between the SRO input and output signals and the nonlinear large-signal behavior of SROs.

Noise Analysis of Super-Regenerative Oscillators in Linear and Nonlinear Modes

A rigorous analysis of noise effects in super-regenerative oscillators (SROs), operating in both linear and nonlinear modes, is presented. For operation in the linear mode, two different analysis methods are presented. One is based on the calculation of linear-time variant (LTV) transfer function with respect to the input signal and the noise sources. The second method is based on a compact semianalytical formulation of the pulsed oscillator under the effect of the quench signal. The compact formulation also enables the analysis of the SRO in the nonlinear mode. It constitutes a fully new mathematical description of SROs, with general applicability, as it is not restricted to a particular oscillator topology. It relies on a numerical nonlinear black-box model of the stand-alone free-running oscillator, extracted from harmonic-balance simulations. This model is introduced into an envelope-domain formulation of the SRO at the fundamental frequency. Both the method based on LTV transfer functions and the semianalytical formulation take into account the cyclostationary nature of the SRO response to the noise sources. In the nonlinear mode, the variances of the amplitude and phase are calculated linearizing the formulation of the pulsed steady-state solution. The particular time variation of the phase variance is explained in detail and related to the onset and extinction of the oscillation in the presence of an RF input signal. The new analysis methods have been validated with both independent circuit-level simulations and measurements.

Analysis of Superregenerative Oscillators in Nonlinear Mode

Superregenerative oscillators in a nonlinear mode are investigated in detail using methodologies based on envelope transient, complemented with additional algorithms. A maximum-detection technique is applied to obtain the input-power threshold for nonlinear operation under different implementations of the quench signal. A mapping procedure enables the prediction of hangover and self-oscillation effects. It is based on the detection of the sequence of local maxima in the envelope amplitude after the application of a single input pulse. Using a contour-intersection method, and depending on the analysis time interval, it is possible to quantify the hangover effects and obtain the oscillation boundary, in terms of any two significant parameters. Then, a compact time-variant behavioral model is derived, valid in the absence of hangover and self-oscillation effects. It consists of a single time-variant Volterra kernel and is applicable provided that the amplitude transitions occur outside the sensitivity interval. Various methodologies are tested in a practical FET-based oscillator at 2.7 GHz. The prototype has been manufactured and measured, obtaining good agreement with the analysis results.

Envelope-Domain Analysis and Modeling of Super-Regenerative Oscillators

An envelope-domain methodology for the numerical modeling of super-regenerative oscillators (SROs) is presented. The main advantage is its generality of application to transistor-based oscillators with arbitrary topology. Initially, a stability analysis of the nonoscillatory steady-state solution, forced by the quench signal, is performed. It is based on the calculation of a linear-time-variant (LTV) transfer function, obtained by linearizing the circuit envelope-domain equations about the nonoscillatory regime. Under moderate quench frequencies, it will be possible to estimate the SRO normalized envelope and sensitivity function from the detected dominant pair of complex-conjugate poles. In the general case, the SRO oscillatory response is modeled with a numerical method, valid under linear operation with respect to the input signal. This is based on the calculation of the LTV impulse response from a time–frequency transfer function obtained under a small-signal sinusoidal excitation. The LTV impulse response enables a straightforward determination of the sensitivity time interval and time distance to the envelope maximum. An integral expression, in terms of the LTV transfer function, will provide the SRO response to any small-signal input with any arbitrarily carrier frequency and modulation. The methodology has been successfully validated through its application to an SRO at 2.7 GHz, which has been manufactured and measured.

Efficient Ultra-High Speed Communication with Simultaneous Phase and Amplitude Regenerative Sampling (SPARS)

Abstract For ultra-high speed communication systems at high center frequencies above 100 GHz, we propose a disruptive change in system architecture to address major issues regarding amplifier chains with a large number of amplifier stages. They cause a high noise figure and high power consumption when operating close to the frequency limits of the underlying semiconductor technologies. Instead of scaling a classic homodyne transceiver system, we employ repeated amplification in single-stage amplifiers through positive feedback as well as synthesizer-free self-mixing demodulation at the receiver to simplify the system architecture notably. Since the amplitude and phase information for the emerging oscillation is defined by the input signal and the oscillator is only turned on for a very short time, it can be left unstabilized and thus come without a PLL. As soon as gain is no longer the most prominent issue, relaxed requirements for all the other major components allow reconsidering their implementation concepts to achieve further improvements compared to classic systems. This paper provides the first comprehensive overview of all major design aspects that need to be addressed upon realizing a SPARS-based transceiver. At system level, we show how to achieve high data rates and a noise performance comparable to classic systems, backed by scaled demonstrator experiments. Regarding the transmitter, design considerations for efficient quadrature modulation are discussed. For the frontend components that replace PA and LNA amplifier chains, implementation techniques for regenerative sampling circuits based on super-regenerative oscillators are presented. Finally, an analog-to-digital converter with outstanding performance and complete interfaces both to the analog baseband as well as to the digital side completes the set of building blocks for efficient ultra-high speed communication.

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.

Design of UWB pulse radio transceiver using statistical correlation technique in frequency domain

Abstract. In this paper, we propose a new technique to extract low power UWB pulse radio signals, near to noise level, using statistical correlation technique in frequency domain. The receiver consists of many narrow bandpass filters which extract energy either from transmitted UWB signal, interfering channels or noise. Transmitted UWB data can be eliminated by statistical correlation of multiple bandpass filter outputs. Super-regenerative oscillators, tuned within UWB spectrum, are designed as bandpass filters. Summers and comparators perform statistical correlation.

A nuclear quadrupole resonance thermometer with frequency locking

A precision thermometer using the NQR absorption of KC10 3 has been developed. The super-regenerative oscillators with frequency locking has been used as the sensor oscillator in order to avoid the defects of the conventional super-regenerative oscillator. To find the frequency locking an FET type super-regenerative oscillator with external quenching and a locking oscillator have been constructed. A special device gives the possibility of stabilizing the line shape at the output of the super-regenerative oscillator. As a result the upper temperature range has been expanded to 430 K.

A nuclear quadrupole resonance spectrometer for the frequency range 250 to 1100 MHz

Two super-regenerative oscillators for an NQR spectrometer have been built covering the frequency range from 250 up to 1100 MHz. The two oscillators of microstrip type use 1/4 lambda or 1/2 lambda resonators, possess sideband suppression and automatic gain control and allow insertion of a finger dewar for low temperature investigations. A series of nitrogen-iodine charge-transfer compounds have been studied.

Measurement of magnetic field contours

A simple apparatus is described which can be used to plot the field contours of a laboratory magnet, even when the instability of the field in time is comparable with the variations in space. It consists of two super-regenerative oscillators which produce signals at the nuclear magnetic resonance frequencies of the proton samples in their tank coils. One sample is fixed while the second scans the magnetic field, and the field difference between the two probes is presented in frequency units on an electronic counter. The method can be extended to make the field mapping operation completely automatic.

Nuclear Quadrupole Resonance of Antimony Isotopes in Solids

Measurements of nuclear quadrupole resonances of antimony isotopes in solids have been made at a relative accuracy of about one part in 10 6 . Detectors are superregenerative oscillators. Relative accuracy was achieved by measurement of two or three resonance frequencies in a very short time. For antimony trichloride the results were almost in agreement with Wang's data, but the resonant frequency ν 3 of the Sb 123 isotope, was higher about 2.5 kc. This implies that the cedecipole coupling constant might not have an order of magnitude which leads to a definitely measurable amount. In antimony oxide the simultaneous measurement was more easy, since it has a small asymmetry parameter. In this case, the deviation of resonance frequencies from a multiple relation is very small. These results are discussed in terms of cedecipole interaction and thermal vibration.

Determination of Nuclear Gyromagnetic Ratios I

Nuclear magnetic resonance absorption peaks have been observed for seventeen nuclear species. The technique used in observing the resonances involves the use of super-regenerative oscillators and is different in many respects from the bridge method of Purcell and the nuclear induction method of Bloch. Resonance absorption has been observed for the following nuclei: ${\mathrm{H}}^{1}$, ${\mathrm{H}}^{2}$, ${\mathrm{Li}}^{7}$, ${\mathrm{Be}}^{9}$, ${\mathrm{B}}^{11}$, ${\mathrm{F}}^{19}$, ${\mathrm{Na}}^{23}$, ${\mathrm{Al}}^{27}$, ${\mathrm{P}}^{31}$, ${\mathrm{Cu}}^{63}$, ${\mathrm{Cu}}^{65}$, ${\mathrm{Br}}^{79}$, ${\mathrm{Br}}^{81}$, ${\mathrm{Rb}}^{85}$, ${\mathrm{Rb}}^{87}$, ${\mathrm{I}}^{127}$, and ${\mathrm{Cs}}^{133}$. By comparison of various resonance peaks with the proton resonance peak observed simultaneously in the same magnetic field, values for nuclear gyromagnetic ratios and nuclear magnetic moments can be determined in terms of the gyromagnetic ratio and the magnetic moment of the proton. The following frequency ratios have been obtained: