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B. Courtois - One of the best experts on this subject based on the ideXlab platform.

  • Analog ALC Crystal Oscillators for high-temperature applications
    IEEE Journal of Solid-State Circuits, 2000
    Co-Authors: R.a. Bianchi, J.m. Karam, B. Courtois
    Abstract:

    Fundamental mode and third-harmonic mode integrated high-performance automatic level controlled (ALC) Crystal Oscillators for high-temperature applications (up to 250 degrees C), are described in this paper. These Oscillators were designed for a pressure measurement system in high-temperature environments, where the output signal is the difference between both generated frequencies. Frequency variations smaller than 0.0001 ppm/s for each oscillator and a frequency drift of about 2.5 ppm/year of the frequency difference are the measured performance concerning, respectively, the short-term (1 s) and long-term frequency stability of these integrated high performance Crystal Oscillators over the 30 degrees C-225 degrees C temperature range. Other important characteristics are the very stable and constant oscillation levels (~1.1 Vpp), the small second-harmonic distortion (~60 dR), and the phase noise (~95 dB at 50 kHz shift). The characteristics of these Oscillators make them also suitable for many other measurement systems (time, temperature, and other physical and chemical quantities), especially if they are constrained to operate under severe temperature conditions

  • Analog ALC Crystal Oscillators for high-temperature applications
    IEEE Journal of Solid-State Circuits, 2000
    Co-Authors: R.a. Bianchi, J.m. Karam, B. Courtois
    Abstract:

    Fundamental mode and third-harmonic mode integrated high-performance automatic level controlled (ALC) Crystal Oscillators for high-temperature applications (up to 250/spl deg/C), are described in this paper. These Oscillators were designed for a pressure measurement system in high-temperature environments, where the output signal is the difference between both generated frequencies. Frequency variations smaller than 0.0001 ppm/s for each oscillator and a frequency drift of about 2.5 ppm/year of the frequency difference are the measured performance concerning, respectively, the short-term (1 s) and long-term frequency stability of these integrated high performance Crystal Oscillators over the 30/spl deg/C-225/spl deg/C temperature range. Other important characteristics are the very stable and constant oscillation levels (/spl sim/1.1 Vpp), the small second-harmonic distortion (/spl sim/60 dR), and the phase noise (/spl sim/95 dB at 50 kHz shift). The characteristics of these Oscillators make them also suitable for many other measurement systems (time, temperature, and other physical and chemical quantities), especially if they are constrained to operate under severe temperature conditions.

R.a. Bianchi - One of the best experts on this subject based on the ideXlab platform.

  • Analog ALC Crystal Oscillators for high-temperature applications
    IEEE Journal of Solid-State Circuits, 2000
    Co-Authors: R.a. Bianchi, J.m. Karam, B. Courtois
    Abstract:

    Fundamental mode and third-harmonic mode integrated high-performance automatic level controlled (ALC) Crystal Oscillators for high-temperature applications (up to 250 degrees C), are described in this paper. These Oscillators were designed for a pressure measurement system in high-temperature environments, where the output signal is the difference between both generated frequencies. Frequency variations smaller than 0.0001 ppm/s for each oscillator and a frequency drift of about 2.5 ppm/year of the frequency difference are the measured performance concerning, respectively, the short-term (1 s) and long-term frequency stability of these integrated high performance Crystal Oscillators over the 30 degrees C-225 degrees C temperature range. Other important characteristics are the very stable and constant oscillation levels (~1.1 Vpp), the small second-harmonic distortion (~60 dR), and the phase noise (~95 dB at 50 kHz shift). The characteristics of these Oscillators make them also suitable for many other measurement systems (time, temperature, and other physical and chemical quantities), especially if they are constrained to operate under severe temperature conditions

  • Analog ALC Crystal Oscillators for high-temperature applications
    IEEE Journal of Solid-State Circuits, 2000
    Co-Authors: R.a. Bianchi, J.m. Karam, B. Courtois
    Abstract:

    Fundamental mode and third-harmonic mode integrated high-performance automatic level controlled (ALC) Crystal Oscillators for high-temperature applications (up to 250/spl deg/C), are described in this paper. These Oscillators were designed for a pressure measurement system in high-temperature environments, where the output signal is the difference between both generated frequencies. Frequency variations smaller than 0.0001 ppm/s for each oscillator and a frequency drift of about 2.5 ppm/year of the frequency difference are the measured performance concerning, respectively, the short-term (1 s) and long-term frequency stability of these integrated high performance Crystal Oscillators over the 30/spl deg/C-225/spl deg/C temperature range. Other important characteristics are the very stable and constant oscillation levels (/spl sim/1.1 Vpp), the small second-harmonic distortion (/spl sim/60 dR), and the phase noise (/spl sim/95 dB at 50 kHz shift). The characteristics of these Oscillators make them also suitable for many other measurement systems (time, temperature, and other physical and chemical quantities), especially if they are constrained to operate under severe temperature conditions.

Ismailyehea - One of the best experts on this subject based on the ideXlab platform.

Xianhe Huang - One of the best experts on this subject based on the ideXlab platform.

  • Prediction, simulation, and verification of the phase noise in 80-MHz low-phase-noise Crystal Oscillators
    IEEE transactions on ultrasonics ferroelectrics and frequency control, 2015
    Co-Authors: Xianhe Huang, Pingping Chen, Junjie Jiao
    Abstract:

    To predict the phase noise in an 80-MHz Crystal oscillator, on the basis of the classical Leeson model, we analyzed and selected the oscillator noise figure F and transistor corner frequency fc reasonably, and then calculated the loaded Q (QL) value of the oscillator according to the parameters in the selected Butler oscillation circuit. Thus, we obtained the predicted phase noise in an 80-MHz Crystal oscillator according to the Leeson phase noise formula. Next, the simulation curve of the phase noise in this 80-MHz low-phase-noise Crystal oscillator was obtained by establishing a transistor nonlinear model using commercial design software. Then, we debugged the 80-MHz low-phase-noise Crystal oscillator prototype under the guidance of the prediction and simulation results and tested it. The measured results show that the phase noise predicted after selecting reasonable parameters for the Leeson model and the ADS simulation curve of the phase noise obtained by using the nonlinear transistor model are both close to the actual measured result. This result may be beneficial in simplifying the design process for low-phase-noise Crystal Oscillators.

  • Analysis and design of low phase noise Crystal Oscillators
    2012 IEEE International Conference on Mechatronics and Automation, 2012
    Co-Authors: Yan Wang, Xianhe Huang
    Abstract:

    The methods to reduce phase noise of Crystal Oscillators are presented and analyzed in the paper. According to analysis of Leeson formula, phase noise has a direct relation with noise factor F, corner frequency f c and loaded quality factor Q L . Based on the method of reducing phase noise by improving Q L , the formula of Q L is derived by analysis of Pierce oscillator circuit and simulated by MATLAB. According to the simulation result, we can draw a conclusion that Q L is explicitly related to circuit parameters. Based on this conclusion, phase noise of a Pierce Crystal oscillator is simulated and analyzed by the Agilent Advanced Design System. The simulated phase noise results are reduced by adjusting circuit parameter. A design of the prototype 120 MHz Pierce Crystal oscillator is presented and the experiments are carried out. The measured near carrier frequency phase noise can achieve −100 dBc/Hz@10Hz and −132 dBc/Hz@100Hz. The simulated and experimental results show that it is feasible to design low phase noise Crystal oscillator based on improving Q L .

  • Research and Simulation on Optimization of Phase Noise in Crystal Oscillators
    Applied Mechanics and Materials, 2012
    Co-Authors: Yan Wang, Xianhe Huang
    Abstract:

    The methods to reduce phase noise of Crystal Oscillators based on Leeson model are presented in the paper. According to analysis of Leeson formula, phase noise has a direct relation with noise factor, corner frequency and loaded quality factor. It can be seen that optimization of phase noise can be realized form these three aspects. The feasibility of these methods to reduce phase noise is analyzed. Based on the method of reducing phase noise by improving loaded quality factor, calculation of loaded quality factor is carried out and phase noise of a Butler Crystal oscillator is simulated by the Agilent Advanced Design System (ADS). The simulation results prove that this method to reduce phase noise based on improving loaded quality factor is feasible and effective.

  • High-frequency overtone TCXO based on mixing of dual Crystal Oscillators
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2007
    Co-Authors: Xianhe Huang, Wei Fu
    Abstract:

    To implement a high-stability and high-frequency overtone temperature-compensated Crystal oscillator (TCXO) conveniently, an improved design of the novel overtone TCXO is described in this paper. A 120-MHz TCXO based on mixing of dual Crystal Oscillators is implemented. It utilizes a 100-MHz AT-cut 5th-overtone Crystal oscillator mixed with a 20-MHz AT-cut voltage-controlled Crystal oscillator (VCXO). The 120-MHz mixed product is filtered to produce the output signal. The total frequency deviation of 20-MHz and 100-MHz Crystal Oscillators is compensated by adjusting the output frequency of the 20-MHz oscillator to produce the stable 120-MHz output frequency. In this work, verifying experimental results of the compensation are presented. The stability of the experimental 120-MHz overtone TCXO with microprocessor temperature compensation achieves plusmn2 times 10-7 over the temperature range from -30degC to +70degC. A phase noise level of -133 dBc/Hz at 1 kHz offset has been initially measured for the prototype TCXO. The experimental result demonstrates this approach can conveniently implement the high-frequency overtone temperature compensation with a relatively high stability, and it is available for a wider frequency range as well.

Serge Galliou - One of the best experts on this subject based on the ideXlab platform.

  • Measurements of ultra-stable langatate Crystal Oscillators
    2009
    Co-Authors: Joël Imbaud, Serge Galliou, J.p. Romand, Philippe Abbé, Roger Bourquin
    Abstract:

    The use of the langatate (LGT, La3Ga5.5Ta0.5O14) Crystal for the realization of ultra-stable Oscillators is very recent. This material proved that it is capable of giving stability results as good as those achieved by quartz Crystal. To the knowledge of the authors, until now there was no substitution material for the quartz Crystal, for low noise applications. Indeed, investigations had proved that LGT is a good alternative. This paper describes quickly all the essential manufacturing steps related to the development of an oscillator using this pure synthetic Crystal. It shows that the performances looked for, in terms of noise, are those obtained with the quartz Crystal. Its content is as follows. It begins with the description of the resonator manufacturing, the resonator being the heart of the oscillator. Then, the development of the related electronics is discussed and noise measurements are given as a conclusion. Very first ageing measurements of a set of LGT Crystal Oscillators are also emphasized. Noise results are given in terms of standard Allan deviation as well as in power spectral density of phase fluctuations. These results are analyzed and finally compared to those of quartz Crystal Oscillators.

  • Noise measurements of 10 MHz LGT Crystal Oscillators
    2007
    Co-Authors: Joël Imbaud, Serge Galliou, J.p. Romand, Philippe Abbé, Roger Bourquin
    Abstract:

    Abstract— our aim is to estimate the potential of LGT resonators to built Oscillators of good stability in the short term domain. This objective needs two conditions: 1) The manufacturing of high Q-factor resonators with a process similar to that used for high stability quartz Crystal resonators. 2) The realization of a scheme of an oven controlled oscillator specifically designed for these resonators. A batch of langatate (LGT) Crystal resonators has been manufactured in our laboratory. A satisfying machining and polishing process is now ready. These resonators are optimized in terms of curvature radius and electrode diameter. They are available in an electrode-deposited version as well as in the electrodeless version, the so-called BVA structure. The energy trapping should still be optimized but here and now good quality factors, closed to 1.4 106, are achieved for 10 MHz, 5th overtone resonators. Presently, their motional parameters are quite different from those of quartz Crystal resonators. Classic topologies of quartz Crystal Oscillators are not well suited for LGT Crystal resonators. Further, the high thermal sensitivity of LGT Crystal resonators (parabolic f-T curve) requires a particular attention on the oven thermal stability. As a consequence, a specific oscillator topology has been designed for an appropriate use of these LGT Crystal resonators. Resulting frequency stabilities are described in terms of Allan variance or power spectral density of frequency fluctuations.

  • Predicting phase noise in Crystal Oscillators
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2005
    Co-Authors: Fabrice Sthal, Serge Galliou, N. Gufflet, M. Mourey
    Abstract:

    In order to predict the phase noise in Crystal Oscillators an enhanced phase-noise model has been built. With this model, the power spectral densities of phase fluctuations can be computed in different points of the oscillator loop. They are calculated from their correlation functions. The resonator-caused noise as well as the amplifier-caused noise are taken into account and distinguished. To validate this enhanced model, the behavior of a batch of 10 MHz quartz Crystal Oscillators is observed and analyzed. The tested batch has been chosen in a facility production. Their associated resonators have been selected according to the value of their resonant frequency and their motional resistance. Open-loop and closed-loop measurements are given. The phase noise of the overall oscillator working in closed loop is provided by the usual active method. Theoretical and experimental results are compared and discussed

  • Predicting phase noise in Crystal Oscillators
    IEEE International Frequency Control Sympposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum 2003. Proceedings of the 20, 2003
    Co-Authors: Serge Galliou, Fabrice Sthal, N. Gufflet, M. Mourey
    Abstract:

    An enhanced phase noise model allows to predict the phase noise in Crystal Oscillators. It is based on an improvement of the mathematical analysis proposed by G. Sauvage. In this model, power spectral densities of phase fluctuations are computed in different points of the oscillator loop. They are calculated from their correlation functions. The resonator caused noise as well as the amplifier caused noise are taken into account and distinguished. In order to validate this model, the behavior of about ten of 10 MHz quartz Crystal Oscillators is observed and analyzed. These Oscillators have been chosen in a facility production. Resonators have been selected according to the value of their resonant frequency and their motional resistance. We attempt to measure separately the amplifier and resonator caused noises by means of a passive method. The phase noise of the overall oscillator working in closed loop is provided by the usual active method. Theoretical and experimental results are compared and discussed.

  • enhanced phase noise model for quartz Crystal Oscillators
    International Frequency Control Symposium, 2002
    Co-Authors: Serge Galliou, Fabrice Sthal, M. Mourey
    Abstract:

    Leeson's model is the basic model for predicting oscillator noise. G. Sauvage [1977] has proposed a mathematical analysis of this "heuristic" model. Both models do not detail the relative importance of the amplifier transfer function associated with its own noise in regard to the resonator. In this paper, an improved version of these previous models is presented. Amplifier noise and that caused by the resonator are distinguished. Power spectral densities of phase noise at various points of the oscillator loop are calculated from their respective correlation functions. As a consequence, the influences of the amplifier and resonator inner noises on the resulting oscillator noise are predictable. Nonlinearities could also be included in this more general model. An example of phase noise modeling of the Clapp quartz Crystal oscillator is simulated and discussed.