Franck Lardet-Vieudrin

FREQUENCY STABILITY ENHANCEMENT FROM CARRIER-ENVELOPE RESONANCE IN A SURFACE ACOUSTIC WAVE DELAY LINE OSCILLATOR

We have built a new injection‐locking set‐up which allows the study of low frequency noise in an oscillator. The interaction between a driving 100 MHz signal and a surface acoustic wave delay line oscillator undergoing a nonlinear modulational instability is investigated. Driving amplitude is used to control the synchronization range and therefore the frequency stability of a newly discovered carrier‐envelope resonance process. In the soliton‐locked regime, fundamental and subharmonic steps attached to a Lorentzian shape frequency‐amplitude characteristic are found. They are explained thanks to a driven nonlinear Schrodinger model and the joined synchronization map.

Detecting response of square and circular Si/AlN/Al membranes transducers by Laser Vibrometry Doppler and Impedancemeter

This paper investigates the vibration analysis of square and circular piezoelectric micro-transducers in the hundred kHz range as a function of experimental tools. These micro-transducers have been actuated by a piezoelectric Aluminum Nitride (AlN) 0.9 μm-thin layer sandwiched between N-doped Silicon (Si) 20μm-thick layer and aluminum (Al) 0.4μm-thin layer. Si/AlN/Al square and circular membranes, with size fixed to 1.5 mm were fabricated using micromachining technology. Analytical and 3D finite element method (3D-FEM) analysis using Comsol software has been performed to model static, modal and vibration behavior of these membranes. Typical numerical simulations and experimental results are presented and discussed. Comparison with standard impedancemeter measurement is shown to assess the performance of Laser Doppler Vibrometry (LDV) system. This works main contribution is mechanical and electrical characterization and comparison with a model.

Detection of out-of-plane and in-plane (XYZ) motions of piezoelectric microcantilever by 3D-Laser Doppler Vibrometry

This paper investigates the vibration analysis of microcantilever in the hundred kHz to MHz range using 3D Vibrometry experimental tool. These microdevices have been actuated by a piezoelectric Aluminum Nitride (AIN) 1.5 μm-thin layer. Analytical and 3D finite element method (3D-FEM) analysis using Comsol software has been performed to model vibration behavior. Typical numerical simulations and experimental results are presented and discussed. We particularly emphasize on the high detection in-plane and out-of plane motions of the microcantilevers actuated piezoelectrically in air environment. The bending, torsion and lateral modes have been successfully demonstrated. The purpose of this article is to review these latest developments tools in the microcantilever dynamic measurement and present an outlook of the future of these characterization in the next generation microsystems.

Mechanical behavior of T-shaped A1N membrane based on thin film elongation acoustic resonator

Microelectromechanical systems (MEMS) move rapidly towards commercialization, the issue of mechanical characterization has emerged as a major consideration in device design and fabrication. This paper investigates the vibration analysis of T shaped membrane which is fully adapted for oscillator circuit miniaturization. This shape has been actuated by a piezoelectric Aluminum Nitride (AlN) 1 μm-thin layer sandwiched between two aluminum electrodes and fabricated using micromachining technology. Analytical and 3D finite element method (3D-FEM) analysis using Comsol software have been performed to model the modal and mechanical vibration behavior, and to estimate the material properties which minimize the difference between the measured and simulated profiles. Typical numerical simulations and experimental results are presented and discussed. The mechanical characterization uses Laser Doppler Vibrometry (LDV) system which is quick, non-destructive, non-contact, with a high accurate detection of resonance frequency. This work main contribution is mechanical characterization and comparison with its model. The performances of the TFEAR presents a Q factor up to 1200 and a motional resistance close to 400 Ω at 12.78 MHz.

Development of a 5 MHz frequency difference pre-multiplier for a short term frequency stability bench of the oscillators

This paper reports the realization of a 5 MHz frequency difference x10 pre-multiplier, developed in the laboratory to replace an obsolete one. The principle we chose is to synthesize a 45 MHz and a 50 MHz from a reference signal and from the signal to be measured, and to subtract one to the other to generate a 5 MHz, whose precision on the measurement is increased by a factor 10. Obtained Allan variance sigmay(tau) at 1 s is 5.10-14 and output spectral density of phase noise floor is about -160 dBc/Hz at 5 MHz.

Synthetic modeling of quartz crystal oscillator

This paper presents a new modeling technique to describe the nonlinear behavior of complicated oscillator circuits. The simulation program being developed first removes the resonator from the oscillation loop and call on SPICE to calculate the large signal /spl gamma/-parameters of the amplifier circuit considered as a nonlinear two-port circuits. The oscillation condition, obtained by reinserting the resonator across the two-port circuit, is expressed under the form of a complex polynomial in the harmonic variable j/spl omega/, the coefficients of this polynomial being nonlinear functions of the signal amplitude. Solving the real and imaginary parts of this characteristic polynomial by using nonlinear analysis algorithm, it is possible to accurately calculate both amplitude and frequency of the oscillation.

Binary coding and correlations in the noise frequencies of an oscillator

We report on a multifractal type approach to the study of low frequency noise in oscillators. The time sequence is interrogated by means of a multiscale local stability exponent which acts as a sliding filtering window. Its discontinuities are reflected into a binary coding of which the correlations are analyzed. The mapping of binary data into a devil’s staircase is used to emphasize the correlated origin of frequency fluctuations.

Toward full crystal oscillator integration for RF applications

This paper presents the performances of an integrated oscillator working at 3.3V power supply for XO applications, extended to OCXO by digital selections. It is realized in a standard 0.35µm SiGe BiCMOS technology from austriamicrosystems AG®. Some experimental characterizations have been performed at 40 MHz and give good agreement with simulations. This die is then used to develop a miniaturized XO design on silicon substrate (8.5×8.5 mm2).

Carrier-to-envelope resonances, quasi periodicity and 1/f frequency noise in an injection-locked oscillator

In our recent work (see IEEE Trans. on UFFC, vol. 43, p. 326, 1996) we reported on a new multiscale processing of the time series of frequency deviations. It allowed us to demonstrate global correlations in the time sequence and to conjecture a possible determinism behind them. In this paper we extend that work in demonstrating experimentally synchronization phenomenon concerning an electronic carrier signal and its low frequency modulations. The effect is termed carrier-to-envelope resonance since it manifests itself at subharmonics pf/sub 0//q (p and q integers, p<q) of the angular carrier frequency f/sub 0/. It is obtained from an original pulse modulating technique in which the pulse duration is slaved to the carrier and the envelope frequencies. In contrast to the conventional phase locked loop scheme, the new set-up gives rise to synchronization states concerning both the amplitude and the frequency of oscillations. This is similar to the energy quantization in quantum mechanics. Thus the carrier-to-envelope frequency ratio is quantized at integer and rational numbers depending on the excitation power.

Frequency stability control of carrier-envelope resonance in a surface acoustic wave delay line oscillator

We have succeeded in measuring and explaining the frequency locking between the carrier and the envelope of a delayed electronic oscillator. It is shown that a nonlinear mapping accounts for the overall features of this synchronization and that the fine structure in the frequency noise can now he understood on a analytical basis. This extends previous work concerned with the origin of the correlations in 1/f frequency noise of a single frequency oscillator. This is an important step towards the development of new kinds of stable devices: frequency dividers, analog to digital converters, neural networks and highly sensitive sensors.