17 results on '"feedback oscillator"'
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2. Design and Simulation of an RF Feedback Oscillator Circuit Using Conventional X-Parameters.
- Author
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Urbina-Martinez, J. L., Loo-Yau, J. R., Reynoso-Hernandez, J. Apolinar, and Moreno, P.
- Abstract
This letter demonstrates for the first time the usefulness of the X-parameters under 50- $\Omega $ load condition (conventional X-parameters) for simulating and designing RF feedback oscillator circuits. The measurement procedure to characterize a GaAs FET ATF34143 with conventional X-parameters is presented. The measured X-parameters’ data are subsequently used in the design of an RF feedback oscillator at 2.47 GHz. The comparison of the experimental results with the harmonic balance simulations demonstrates the strengths and weakness that conventional X-parameters have to predict the electrical behavior of the feedback oscillator. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
3. Low Phase-Noise Oscillator Design Using Large Signal Transfer Function and Complex Quality Factor
- Author
-
Selçuk, Gökhun, Kurt, Sinan, Selçuk, Gökhun, and Kurt, Sinan
- Abstract
In this study we use large signal closed loop transfer function and complex quality factor to design a low phase noise feedback oscillator. The method offers two major advantages. First it evaluates the closed loop transfer function, which inherently takes into account the impedance mismatch between the elements of the loop and the nonlinear behavior of the active device. These factors affect the loaded quality factor of the frequency stabilization element, as well as the location of frequency at which minimum phase noise is obtained. Secondly the method uses complex quality factor to estimate the frequency of best phase noise performance. Unlike the conventional quality factor which only uses the derivative of phase response, complex quality factor takes into account both amplitude and phase variations and provide better insight for low noise design. It has been shown experimentally that complex quality factor changes significantly for saturated loop. By using complex quality factor of saturated loop, phase noise performance can be more accurately predicted compared to the methods which do not take saturation effects into account., Univ Salamanca, IEEE Spanish Sect, IEEE Reg 8, Ayuntamiento Ciudad Rodrigo, Ayuntamiento Salamanca, Startup OLE, Altiria
- Published
- 2021
4. Compact Vital Signal Sensor Using Oscillation Frequency Deviation.
- Author
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Kim, Sang-Gyu, Yun, Gi-Ho, and Yook, Jong-Gwan
- Subjects
- *
DETECTORS , *OSCILLATIONS , *FREQUENCY deviation (Radio frequency modulation) , *RESPIRATION , *HEART beat , *ELECTRONIC feedback , *RADIATORS , *WAVE analysis - Abstract
In this paper, a compact vital signal sensing method using oscillation frequency deviation at 2.4-GHz industrial–scientific–medical band is proposed to detect vital signals, such as heartbeat and respiration signal. The oscillation circuit of the proposed vital sensor system has been realized by a planar resonator, which functions as a positive feedback element, as well as a near-field radiator to sense vital signals, simultaneously. The periodic movement of a body by respiration exercise causes the impedance variation of the radiator within the near-field range. The impedance variation results in a corresponding change in the oscillation frequency, and this variation has been utilized for sensing of the vital signals. In addition, a surface acoustic wave filter and power detector have been used to increase the sensitivity of the system and to transform the frequency variation to voltage waveform. The experimental results show that the proposed vital sensor placed 20 mm from the body can detect the heartbeat waveform very accurately. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
5. Analysis of Stabilization Circuits for Phase-Noise Reduction in Microwave Oscillators.
- Author
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Suárez, Almudena and Ramirez, Franco
- Subjects
- *
MICROWAVE oscillators , *ELECTRIC equipment , *MICROWAVE devices , *ELECTRONIC circuits , *FREQUENCY discriminators , *MICROWAVES - Abstract
Two configurations for oscillator phase-noise reduction using stabilization circuits have been demonstrated in the literature. One of them is based on the self-injection of the oscillator signal, after it passes through a long delay line or a high-quality-factor resonator. The second one is a stabilization loop, containing a frequency discriminator. In this paper, an in-depth analytical comparison of these two configurations, respectively based on injection locking and phase-locking principles, is presented. Analytical expressions are provided for the variation of the steady-state solution and its phase noise versus the parameters of the feedback network. The expressions are rigorously validated with harmonic balance. Instabilities reported by other authors are investigated through bifurcation analysis. The new expressions enable a good understanding of the amplitude and frequency jumps and sharp phase-noise maxima obtained simulations and measurements versus the feedback parameters. A practical 5-GHz voltage-controlled oscillator has also been implemented, for validation purposes. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
6. Low phase noise microwave oscillators based on HTS shielded dielectric resonators.
- Author
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Ghosh, I.S., Tellmann, N., Schemion, D., Scholen, A., and Klein, N.
- Subjects
- *
MICROWAVE oscillators , *MICROWAVE devices , *ELECTRIC oscillators , *HIGH temperature superconductivity research , *HIGH temperature superconductors - Abstract
To meet the specifications of future radar and communication systems we developed a low phase noise microwave oscillator. This feedback oscillator consists of a commercial MESFET-amplifier at room temperature and a LaAlO/sub 3/ dielectric resonator with high temperature superconducting (HTS) shielding at 63 K. The resonator operating at a resonance frequency of 5.6 GHz showed unloaded quality factors in the 10/sup 5/ to 10/sup 6/ range. By means of a strong resonator coupling (|S/sub 21/|=6 dB) and an amplifier gain of 20 dB we obtained an output power of +15 dBm. The phase noise L(f/sub m/) of the oscillator was below the detection limit for offset frequencies beyond 10 kHz. For offset frequencies below 5 kHz measurements revealed perfect L(f/sub m/)/spl prop/f/sub m//sup .3/-behaviour according to the Leeson model. The phase noise was -110 dBc/Hz at 1 kHz offset and -130 dBc/Hz at 10 kHz. This phase noise performance is superior to state of the art SAW- or quartz oscillators for f/sub m/>10 kHz. To further reduce the phase noise performance close to the carrier we investigated the implementation of a phase locked loop (PLL). The long term temperature stability of the oscillator frequency can be enhanced by introducing a central cylinder made from rutile (TiO/sub 2/). We present numerical and experimental results on this compensation. [ABSTRACT FROM PUBLISHER]
- Published
- 1997
- Full Text
- View/download PDF
7. Low cost microwave oscillator using substrate integrated waveguide cavity.
- Author
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Cassivi, Y. and Wu, K.
- Abstract
A topology is proposed for designing a low-cost microwave oscillator. This new feedback oscillator makes use of a substrate integrated waveguide (SIW) cavity that acts as a frequency selector as well as a feedback-coupling device. The oscillator is stabilized by using an injection-locking scheme. A 12.02-GHz oscillator prototype was designed. Experimental results for phase noise, locking range, and quality factor of the new circuit are presented. An external Q of 178 was measured. [ABSTRACT FROM PUBLISHER]
- Published
- 2003
- Full Text
- View/download PDF
8. Discussion on the general oscillation startup condition and the Barkhausen criterion
- Author
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He, Fan, Ribas, Raymond, Lahuec, Cyril, and Jézéquel, Michel
- Published
- 2009
- Full Text
- View/download PDF
9. Self-sustained oscillation phenomena of fluidic flowmeters
- Author
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Yamamoto K., Hiroki F., and Hyodo K.
- Published
- 1999
- Full Text
- View/download PDF
10. Optimal operating points of oscillators using nonlinear resonators
- Author
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Michael L. Roukes, Eyal Kenig, Luis Guillermo Villanueva, Matthew H. Matheny, R. B. Karabalin, Ron Lifshitz, and Michael Cross
- Subjects
amplifier-noise ,FOS: Physical sciences ,Y-factor ,Noise figure ,Noise (electronics) ,Article ,Control theory ,Oscillometry ,Phase noise ,Effective input noise temperature ,Computer Simulation ,Mathematics ,Noise temperature ,model ,Models, Statistical ,Oscillator phase noise ,Quantum noise ,Nonlinear Sciences - Chaotic Dynamics ,feedback oscillator ,phase noise ,Condensed Matter - Other Condensed Matter ,Nonlinear Dynamics ,Chaotic Dynamics (nlin.CD) ,classical noise ,Algorithms ,Other Condensed Matter (cond-mat.other) - Abstract
We demonstrate an analytical method for calculating the phase sensitivity of a class of oscillators whose phase does not affect the time evolution of the other dynamic variables. We show that such oscillators possess the possibility for complete phase noise elimination. We apply the method to a feedback oscillator which employs a high Q weakly nonlinear resonator and provide explicit parameter values for which the feedback phase noise is completely eliminated and others for which there is no amplitude-phase noise conversion. We then establish an operational mode of the oscillator which optimizes its performance by diminishing the feedback noise in both quadratures, thermal noise, and quality factor fluctuations. We also study the spectrum of the oscillator and provide specific results for the case of 1/f noise sources.
- Published
- 2012
11. ARC oscilátor s bloky s řiditelným parametrem
- Author
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Slezák, Josef, Kolka, Zdeněk, Bořecký, Tomáš, Slezák, Josef, Kolka, Zdeněk, and Bořecký, Tomáš
- Abstract
V rámci diplomové práce je provedeno srovnání různých zapojení ARC oscilátorů s ohledem na velikost jejich harmonického zkreslení. Je rozebráno zapojení jednotlivých bloků oscilátoru. Pozornost je věnována výběru a návrhu vhodného ARC filtru a možnostem jeho přeladění. Rovněž je pojednáno o možnostech stabilizace amplitudy kmitů, přičemž jsou uvedena různá zapojení řízených zesilovačů a obvodů pro řízení jejich zesílení. V další části je proveden návrh a simulace ARC oscilátoru. Simulacemi bylo zjištěno, že oscilátor je možno přeladit v kmitočtovém pásmu 100 Hz až 20 kHz s harmonickým zkreslením menším než 1%. V závěru diplomové práce je popsána realizace navrženého zapojení a jsou zde uvedeny výsledky změřených parametrů oscilátoru., Within the master’s thesis there is comparison of different structures of ARC oscillators with respect to their harmonic distortion. Individual blocks of oscillator are analyzed. Attention is paid to choosing and design of suitable ARC filter structure and possibilities of its tuning. Also possibilities of stabilization of amplitude are analyzed. Different types of controlled amplifiers and circuits for controlling of their amplification are discussed. Next captures are focused to designing and simulation of the ARC oscillator. The oscillator can be tuned in the frequency range from 100 Hz to 20 kHz with harmonic distortion smaller than 1%. At the end of the thesis, practical realization of the proposed circuit is described. Also results of the measurement of parameters of the oscillator are given.
12. ARC oscilátor s bloky s řiditelným parametrem
- Author
-
Slezák, Josef, Kolka, Zdeněk, Bořecký, Tomáš, Slezák, Josef, Kolka, Zdeněk, and Bořecký, Tomáš
- Abstract
V rámci diplomové práce je provedeno srovnání různých zapojení ARC oscilátorů s ohledem na velikost jejich harmonického zkreslení. Je rozebráno zapojení jednotlivých bloků oscilátoru. Pozornost je věnována výběru a návrhu vhodného ARC filtru a možnostem jeho přeladění. Rovněž je pojednáno o možnostech stabilizace amplitudy kmitů, přičemž jsou uvedena různá zapojení řízených zesilovačů a obvodů pro řízení jejich zesílení. V další části je proveden návrh a simulace ARC oscilátoru. Simulacemi bylo zjištěno, že oscilátor je možno přeladit v kmitočtovém pásmu 100 Hz až 20 kHz s harmonickým zkreslením menším než 1%. V závěru diplomové práce je popsána realizace navrženého zapojení a jsou zde uvedeny výsledky změřených parametrů oscilátoru., Within the master’s thesis there is comparison of different structures of ARC oscillators with respect to their harmonic distortion. Individual blocks of oscillator are analyzed. Attention is paid to choosing and design of suitable ARC filter structure and possibilities of its tuning. Also possibilities of stabilization of amplitude are analyzed. Different types of controlled amplifiers and circuits for controlling of their amplification are discussed. Next captures are focused to designing and simulation of the ARC oscillator. The oscillator can be tuned in the frequency range from 100 Hz to 20 kHz with harmonic distortion smaller than 1%. At the end of the thesis, practical realization of the proposed circuit is described. Also results of the measurement of parameters of the oscillator are given.
13. ARC oscilátor s bloky s řiditelným parametrem
- Author
-
Slezák, Josef, Kolka, Zdeněk, Slezák, Josef, and Kolka, Zdeněk
- Abstract
V rámci diplomové práce je provedeno srovnání různých zapojení ARC oscilátorů s ohledem na velikost jejich harmonického zkreslení. Je rozebráno zapojení jednotlivých bloků oscilátoru. Pozornost je věnována výběru a návrhu vhodného ARC filtru a možnostem jeho přeladění. Rovněž je pojednáno o možnostech stabilizace amplitudy kmitů, přičemž jsou uvedena různá zapojení řízených zesilovačů a obvodů pro řízení jejich zesílení. V další části je proveden návrh a simulace ARC oscilátoru. Simulacemi bylo zjištěno, že oscilátor je možno přeladit v kmitočtovém pásmu 100 Hz až 20 kHz s harmonickým zkreslením menším než 1%. V závěru diplomové práce je popsána realizace navrženého zapojení a jsou zde uvedeny výsledky změřených parametrů oscilátoru., Within the master’s thesis there is comparison of different structures of ARC oscillators with respect to their harmonic distortion. Individual blocks of oscillator are analyzed. Attention is paid to choosing and design of suitable ARC filter structure and possibilities of its tuning. Also possibilities of stabilization of amplitude are analyzed. Different types of controlled amplifiers and circuits for controlling of their amplification are discussed. Next captures are focused to designing and simulation of the ARC oscillator. The oscillator can be tuned in the frequency range from 100 Hz to 20 kHz with harmonic distortion smaller than 1%. At the end of the thesis, practical realization of the proposed circuit is described. Also results of the measurement of parameters of the oscillator are given.
14. ARC oscilátor s bloky s řiditelným parametrem
- Author
-
Slezák, Josef, Kolka, Zdeněk, Slezák, Josef, and Kolka, Zdeněk
- Abstract
V rámci diplomové práce je provedeno srovnání různých zapojení ARC oscilátorů s ohledem na velikost jejich harmonického zkreslení. Je rozebráno zapojení jednotlivých bloků oscilátoru. Pozornost je věnována výběru a návrhu vhodného ARC filtru a možnostem jeho přeladění. Rovněž je pojednáno o možnostech stabilizace amplitudy kmitů, přičemž jsou uvedena různá zapojení řízených zesilovačů a obvodů pro řízení jejich zesílení. V další části je proveden návrh a simulace ARC oscilátoru. Simulacemi bylo zjištěno, že oscilátor je možno přeladit v kmitočtovém pásmu 100 Hz až 20 kHz s harmonickým zkreslením menším než 1%. V závěru diplomové práce je popsána realizace navrženého zapojení a jsou zde uvedeny výsledky změřených parametrů oscilátoru., Within the master’s thesis there is comparison of different structures of ARC oscillators with respect to their harmonic distortion. Individual blocks of oscillator are analyzed. Attention is paid to choosing and design of suitable ARC filter structure and possibilities of its tuning. Also possibilities of stabilization of amplitude are analyzed. Different types of controlled amplifiers and circuits for controlling of their amplification are discussed. Next captures are focused to designing and simulation of the ARC oscillator. The oscillator can be tuned in the frequency range from 100 Hz to 20 kHz with harmonic distortion smaller than 1%. At the end of the thesis, practical realization of the proposed circuit is described. Also results of the measurement of parameters of the oscillator are given.
15. ARC oscilátor s bloky s řiditelným parametrem
- Author
-
Slezák, Josef, Kolka, Zdeněk, Bořecký, Tomáš, Slezák, Josef, Kolka, Zdeněk, and Bořecký, Tomáš
- Abstract
V rámci diplomové práce je provedeno srovnání různých zapojení ARC oscilátorů s ohledem na velikost jejich harmonického zkreslení. Je rozebráno zapojení jednotlivých bloků oscilátoru. Pozornost je věnována výběru a návrhu vhodného ARC filtru a možnostem jeho přeladění. Rovněž je pojednáno o možnostech stabilizace amplitudy kmitů, přičemž jsou uvedena různá zapojení řízených zesilovačů a obvodů pro řízení jejich zesílení. V další části je proveden návrh a simulace ARC oscilátoru. Simulacemi bylo zjištěno, že oscilátor je možno přeladit v kmitočtovém pásmu 100 Hz až 20 kHz s harmonickým zkreslením menším než 1%. V závěru diplomové práce je popsána realizace navrženého zapojení a jsou zde uvedeny výsledky změřených parametrů oscilátoru., Within the master’s thesis there is comparison of different structures of ARC oscillators with respect to their harmonic distortion. Individual blocks of oscillator are analyzed. Attention is paid to choosing and design of suitable ARC filter structure and possibilities of its tuning. Also possibilities of stabilization of amplitude are analyzed. Different types of controlled amplifiers and circuits for controlling of their amplification are discussed. Next captures are focused to designing and simulation of the ARC oscillator. The oscillator can be tuned in the frequency range from 100 Hz to 20 kHz with harmonic distortion smaller than 1%. At the end of the thesis, practical realization of the proposed circuit is described. Also results of the measurement of parameters of the oscillator are given.
16. A Front-End CMOS Interface Circuit With High Voltage Charge Pump and Oscillator for Capacitive Micromachined Ultrasonic Transducers
- Author
-
Yihe Zhao, Gian Luca Barbruni, Zhikang Li, Libo Zhao, Xiaozhang Wang, Kaifei Wang, Zhuangde Jiang, and Sandro Carrara
- Subjects
oscillators ,resonant chemical sensor ,resonant frequency ,high-voltage techniques ,resonators ,biosensors ,sensitivity ,feedback oscillator ,capacitive micromachined ultrasonic transducers (cmuts) ,application-specific integrated circuit (asic) ,high voltage charge pump ,co2 ,Electrical and Electronic Engineering ,ultrasonic transducers - Abstract
Label-free biosensors, combined with miniaturized micro-electromechanical sensory platforms, offer an attractive solution for real-time and facile monitoring of biomolecules due to their high sensitivity and selectivity without the need for specifically labeling. Resonators have been acknowledged as an efficient technology for measuring biomolecular binding events including those involving nucleic acid and antibody. Among these, capacitive micromachined ultrasonic transducers (CMUTs) have emerged as a promising candidate for biosensing. However, their usage is often limited by the requirement for high voltage supply and continuous frequency tracking, which can result in significant parasitic effects and measurement errors. In this brief, we present a novel front-end interface circuit for a CMUTs-based biosensor. The circuit, fabricated using TSMC 0.18-mu m BipolarCMOS-DMOS (BCD) technology, incorporates an on-chip high voltage charge pump and feedback frequency monitoring. The CMUTs array features 20 x 20 circular cells, fabricated using a low-temperature direct bonding technology, with an experimental parallel-resonant frequency of 1.724 MHz and a high quality factor of up to 40.9. To fit the measured electrical characteristics, a five-element equivalent lumped element model is proposed. The high voltage charge pump provides an output voltage of similar to 20 V, while the feedback oscillator has a ms-level start-up time and a total power dissipation of 3.8 mW. The proposed frontend interface is designed to function as a stand-alone chip for CMUTs-based resonant biodetection.
17. Low Phase-Noise Oscillator Design Using Large Signal Transfer Function and Complex Quality Factor
- Subjects
complex quality factor ,feedback oscillator ,phase noise - Abstract
In this study we use large signal closed loop transfer function and complex quality factor to design a low phase noise feedback oscillator. The method offers two major advantages. First it evaluates the closed loop transfer function, which inherently takes into account the impedance mismatch between the elements of the loop and the nonlinear behavior of the active device. These factors affect the loaded quality factor of the frequency stabilization element, as well as the location of frequency at which minimum phase noise is obtained. Secondly the method uses complex quality factor to estimate the frequency of best phase noise performance. Unlike the conventional quality factor which only uses the derivative of phase response, complex quality factor takes into account both amplitude and phase variations and provide better insight for low noise design. It has been shown experimentally that complex quality factor changes significantly for saturated loop. By using complex quality factor of saturated loop, phase noise performance can be more accurately predicted compared to the methods which do not take saturation effects into account.
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