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Showing papers on "Frequency drift published in 2013"


Journal ArticleDOI
18 Apr 2013
TL;DR: This work introduces a method that requires no additional sample preparation, is simple to implement and simultaneously corrects for x, y and z drift, and is widely applicable in terms of both sample type and microscopy technique.
Abstract: Super-resolution microscopy techniques are often extremely susceptible to sample drift due to their high spatial resolution and the long time needed for data acquisition. While several techniques for stabilizing against drift exist, many require complicated additional hardware or intrusive sample preparations. We introduce a method that requires no additional sample preparation, is simple to implement and simultaneously corrects for x, y and z drift. We use bright-field images of the specimen itself to calculate drift in all three dimensions: x, y and z. Bright-field images are acquired on an inexpensive CCD. By correlating each acquired bright-field image with an in-focus and two out-of-focus reference images we determine and actively correct for drift at rates of a few Hertz. This method can maintain stability to within 10 nm for x and y and 20 nm for z over several minutes. Our active drift stabilization system is capable of simultaneously compensating x, y and z drift through an image-based correlation method that requires no special sample treatment or extensive microscope modifications. While other techniques may provide better stability, especially for higher frequency drift, our method is easy to implement and widely applicable in terms of both sample type and microscopy technique.

88 citations


Journal ArticleDOI
TL;DR: In this article, a novel instantaneous frequency measurement system based on a programmable photonic chip frequency discriminator is experimentally demonstrated, where the microwave signal whose frequency is to be measured is used to modulate the phase of an optical carrier, and an ORR in an add-drop configuration is used as a phase-to-intensity modulation converter.
Abstract: A novel instantaneous frequency measurement system based on a programmable photonic chip frequency discriminator is experimentally demonstrated. The microwave signal whose frequency is to be measured is used to modulate the phase of an optical carrier. An optical ring resonator (ORR) in an add-drop configuration is used as a phase-to-intensity modulation converter. By simultaneously using the through and drop outputs of the ORR, an amplitude comparison function (ACF) can be established. Using this ACF, frequency estimation with a standard deviation of 93.6 MHz in the frequency range of 0.5-4 GHz can be achieved. The ACF is fully programmable by tuning the ORR resonance. This is the first demonstration of an instantaneous frequency measurement system using a compact programmable photonic chip.

71 citations


Journal ArticleDOI
TL;DR: In this article, a uniformly distributed matrix of silicon dioxide pillars is embedded inside the silicon substrate to form a homogenous composite silicon oxide platform (SilOx) with nearly perfect temperature-compensated stiffness moduli.
Abstract: This paper presents a passive temperature compensation technique that can provide full cancellation of the linear temperature coefficient of frequency (TCF1) in silicon resonators. A uniformly distributed matrix of silicon dioxide pillars is embedded inside the silicon substrate to form a homogenous composite silicon oxide platform (SilOx) with nearly perfect temperature-compensated stiffness moduli. This composite platform enables the implementation of temperature-stable microresonators operating in any desired in- and out-of-plane resonance modes. Full compensation of TCF1 is achieved for extensional and shear modes of SilOx resonators resulting in a quadratic temperature characteristic with an overall frequency drift as low as 83 ppm over the industrial temperature range ( -40°C to 80°C). Besides a 40 times reduction in temperature-induced frequency drift in this range, SilOx resonators exhibit improved temperature stability of Q compared with their single crystal silicon counterparts.

62 citations


Journal ArticleDOI
TL;DR: In order to guarantee a robust performance over process-voltage-temperature (PVT) variations of the conventional frequency synthesizer, a frequency calibration scheme is proposed to automatically correct a frequency drift of quadrature injection locked oscillators.
Abstract: This paper proposes a sub-harmonic injection-locked frequency synthesizer with frequency calibration scheme for millimeter-wave Time-division Duplexing (TDD) transceivers. The proposed synthesizer is capable of supporting all 60 GHz channels (58.1-65 GHz) including channel-bonding defined by 60 GHz wireless standards for short-range high-speed wireless communications. In order to guarantee a robust performance over process-voltage-temperature (PVT) variations of the conventional frequency synthesizer, a frequency calibration scheme is proposed to automatically correct a frequency drift of quadrature injection locked oscillators. Implemented by a 65 nm CMOS process, the frequency synthesizer achieves a typical phase noise of -117 dBc/Hz @ 10 MHz offset from a carrier frequency of 61.56 GHz while consuming 72 mW from a 1.2 V supply. The calibration system consumes 65 mW additionally.

57 citations


Journal ArticleDOI
TL;DR: In this article, a model for dm-fiber bursts that is based on assuming fast sausage magnetoacoustic wave trains that propagate along a dense vertical filament or current sheet was presented.
Abstract: Aims. We present a model for dm-fiber bursts that is based on assuming fast sausage magnetoacoustic wave trains that propagate along a dense vertical filament or current sheet.Methods. Eight groups of dm-fiber bursts that were observed during solar flares were selected and analyzed by the wavelet analysis method. To model these fiber bursts we built a semi-empirical model. We also did magnetohydrodynamic simulations of a propagation of the magnetoacoustic wave train in a vertical and gravitationally stratified current sheet.Results. In the wavelet spectra of the fiber bursts computed at different radio frequencies we found the wavelet tadpoles, whose head maxima have the same frequency drift as the drift of fiber bursts. It indicates that the drift of these fiber bursts can be explained by the propagating fast sausage magnetoacoustic wave train. Using new semi-empirical and magnetohydrodynamic models with a simple radio emission model we generated the artificial radio spectra of the fiber bursts, which are similar to the observed ones.

57 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a complete characterization of a laser setup for rubidium cooling dedicated to space applications, which is realized with commercial off-the-shelf fiber components suitable for space applications.
Abstract: We present the complete characterization of a laser setup for rubidium cooling dedicated to space applications. The experimental setup is realized with commercial off-the-shelf fiber components suitable for space applications. By frequency doubling two fiber laser diodes at 1560 nm, we produce the two optical frequencies at 780 nm required for atomic cooling of $^{87}$Rb. The first laser is locked on saturated absorption signal and long term frequency drift has been canceled using a digital integrator. The optical frequency of the second laser is controlled relatively to the first one by a frequency comparison method. A full characterization of the setup, including frequency stability evaluation and frequency noise measurement has been performed. The optical frequency doubling module has been submitted to environmental tests to verify its compatibility with space applications.

50 citations


Journal ArticleDOI
TL;DR: An optoelectronic oscillator (OEO) with wideband frequency tunability and stable output based on a bandpass microwave photonic filter (MPF) has been proposed and experimentally demonstrated.
Abstract: An optoelectronic oscillator (OEO) with wideband frequency tunability and stable output based on a bandpass microwave photonic filter (MPF) has been proposed and experimentally demonstrated. Realized by cascading a finite impulse response (FIR) filter and an infinite impulse response (IIR) filter together, the tunable bandpass MPF successfully replaces the narrowband electrical bandpass filter in a conventional single-loop OEO and serves as the oscillating frequency selector. The FIR filter is based on a tunable multi-wavelength laser and dispersion compensation fiber (DCF) while the IIR filter is simply based on an optical loop. Utilizing a long length of DCF as the dispersion medium for the FIR filter also provides a long delay line for the OEO feedback cavity and as a result, optical tuning over a wide frequency range can be achieved without sacrificing the quality of the generated signal. By tuning the wavelength spacing of the multi-wavelength laser, the oscillation frequency can be tuned from 6.88 GHz to 12.79 GHz with an average step-size of 0.128 GHz. The maximum frequency drift of the generated 10 GHz signal is observed to be 1.923 kHz over 1 hour and its phase noise reaches the -112 dBc/Hz limit of our measuring equipment at 10 kHz offset frequency.

39 citations


Journal ArticleDOI
TL;DR: In this article, the authors explored the piezoelectric transduction of in-plane flexural-mode silicon resonators with a center frequency in the range of 13-16 MHz.
Abstract: In this paper, we explore the piezoelectric transduction of in-plane flexural-mode silicon resonators with a center frequency in the range of 13-16 MHz A novel technique utilizing oxide-refilled trenches is implemented to achieve efficient temperature compensation These trenches are encapsulated within the silicon resonator body so as to protect them during the device release process By using this method, we demonstrate a high-Q (> 19 000) resonator having a low temperature coefficient of frequency of <; 2 ppm/°C and a turnover temperature of around 90 °C, ideally suited for use in an ovenized platform Using electrostatic tuning, the temperature sensitivity of the resonator is compensated across a temperature range of +50 °C to +85 °C, demonstrating a frequency instability of less than 1 ppm Using proportional feedback control on the applied electrostatic potential, the resonator frequency drift is reduced to less than 110 ppb during 1 h of continuous operation, indicating the ultimate stability that can be achieved for the resonator as a timing reference The resonators show no visible distortion up to -1 dBm of input power, indicating their power handling capability

37 citations


Journal ArticleDOI
TL;DR: In this paper, a dualmode voltage-controlled oscillator (DMVCO) and a DMVCO-based wideband frequency synthesizer for software-defined radio applications are presented.
Abstract: This paper presents a dual-mode voltage-controlled oscillator (DMVCO) and a DMVCO-based wideband frequency synthesizer for software-defined radio applications. The DMVCO allows the synthesizer to leverage single-sideband (SSB) mixing, a power efficient approach, for high-frequency local oscillator (LO) signal generation, without the need of poly-phase filter or quadrature voltage-controlled oscillator (QVCO). When compared to the QVCO approach, the DMVCO solution allows the synthesizer to provide continuous LO signals without frequency gaps. The synthesizer is implemented in a 0.13-μm CMOS technology, occupying an active area of 2.2 mm2 and consuming 34-77 mW of power. It provides in-phase and quadrature-phase LO signals over the frequency bands of 0.4-3- and 5-6 GHz and differential LO signals from 0.4 to 6 GHz, supporting major wireless standards including DVB-T, GSM, WCDMA, TD-SCDMA, WLAN802.11 a/b/g, and Bluetooth. The measured phase noises are -135 and -124 dBc/Hz at 3-MHz offset under 1.8- and 5.15-GHz carriers, respectively. The measured spurious tones are less than - 42 dBc at the SSB mixer output.

30 citations


Journal ArticleDOI
TL;DR: In this article, the authors present an empirical DORIS observation corrective model, based on the application of the frequency drift derived from the previously created grid map, which strongly reduces the SAA bias.

28 citations


Journal ArticleDOI
Yang Jiang1, Guangfu Bai1, Lin Hu1, Hengwen Li1, Zhuya Zhou1, Jing Xu1, Shunyan Wang1 
TL;DR: In this paper, the authors proposed a new injection-locked optoelectronic oscillator (OEO) which is locked by a low frequency RF signal and without adding high speed devices.
Abstract: We propose a new injection-locked optoelectronic oscillator (OEO) which is locked by a low frequency RF signal and without adding high speed devices. From a low frequency modulated optical carrier, the injection-locking effect in a Fabry-Perot laser diode is able to generate and selectively amplify one high order harmonic component, which is subsequently injected into a single-loop OEO to lock one of the oscillation modes. This process can improve the injected signal quality and simultaneously implement a single-mode OEO with precise oscillation frequency. In the experiment demonstration, a 20-GHz single-mode OEO locked by a 1-GHz RF signal is obtained. The measured side-mode suppression ratio is 65 dB and the phase noise at 1-kHz frequency offset is -94.7ndBc/Hz.

Proceedings ArticleDOI
21 Jul 2013
TL;DR: In this paper, an adaptive synchronous reference frame phase locked loop (ASRF-PLL) with islanding detection capability is proposed, which provides stable operation under various grid conditions and maintains stable frequency reference during islanding mode.
Abstract: Accurate detection of grid voltage phase angle under fault and distorted voltage conditions is essential for distributed generation (DG). Failure to detect supply voltage phase angle accurately will lead to frequency fluctuation, power oscillation and harmonic currents. For Microgrid applications, the synchronization mechanism should be able to detect the frequency drift during islanding mode and provide stable frequency reference for standalone operation. To realize this goal, an adaptive synchronous reference frame phase locked loop (ASRF-PLL) with islanding detection capability is proposed. A reconfigurable inverter controller that supports both gird connected and stand-alone operation modes is also proposed. This provides stable operation under various grid conditions and maintains stable frequency reference during islanding mode. Simulation results were carried out to validate the proposed PLL to synchronies the power converter link between the Microgrid with hybrid generation and the AC Grid. The proposed PLL was implemented using the dSPACE 1103. The experimental results confirm excellent performance of the proposed technique and agree with the simulation results moreover. The proposed PLL performance was compared with the conventional SRF-PLL. The results verify the validity of the proposed PLL showing its ability to maintain stable operation under various conditions.

Journal ArticleDOI
TL;DR: In this paper, the first fully integrated GaN-based Lamb-wave oscillator on Si substrate for high temperature operation was implemented by monolithically integrating a two-port Lambwave delay line with electronics using AlGaN/GaN high electron mobility transistors (HEMTs).
Abstract: This letter presents the first fully integrated GaN-based Lamb-wave oscillator on Si substrate for high temperature operation. The 58 MHz oscillator prototype was implemented by monolithically integrating a two-port Lamb-wave delay line with electronics using AlGaN/GaN high electron mobility transistors (HEMTs). Electrical characterization from room temperature (RT) up to 250°C was performed on the open-loop Lamb-wave delay line device and the integrated oscillator. It is shown that this oscillator is able to deliver high output power (>11 dBm) up to 250°C. Over the temperature range from RT to 230°C, the oscillation frequency exhibits a linear dependence on temperature with a small temperature coefficient of frequency (TCF) of -47.5 ppm/°C. The frequency drift is less than 1%.

Journal ArticleDOI
TL;DR: A compact, robust device for simultaneous absolute frequency stabilization of three diode lasers whose carrier frequencies can be chosen freely relative to the reference, which significantly supports and improves the clock's operation.
Abstract: We have demonstrated a compact, robust device for simultaneous absolute frequency stabilization of three diode lasers whose carrier frequencies can be chosen freely relative to the reference. A rigid ULE multicavity block is employed, and, for each laser, the sideband locking technique is applied. A small lock error, computer control of frequency offset, wide range of frequency offset, simple construction, and robust operation are the useful features of the system. One concrete application is as a stabilization unit for the cooling and trapping lasers of a neutral-atom lattice clock. The device significantly supports and improves the clock’s operation. The laser with the most stringent requirements imposed by this application is stabilized to a line width of 70 Hz, and a residual frequency drift less than 0.5 Hz/s. The carrier optical frequency can be tuned over 350 MHz while in lock.

Journal ArticleDOI
TL;DR: In this article, the authors investigate linear growth rate using the Waves in a Homogeneous, Anisotropic, Multi-component Plasma dispersion solver and locally observed electron phase space density measurements from the Electron Spectrometer sensor of the Cassini Radio and Plasma Wave Science Investigation to determine the parameters responsible for the variation in chorus intensity and bandwidth.
Abstract: [1] Whistler mode chorus plasma wave emissions have been observed at Saturn near the magnetic equator and the source region. During crossings of the magnetic equator along nearly constant L shells, the Cassini Radio and Plasma Wave Science Investigation often observes a local decrease in whistler mode intensity and bandwidth closest to the magnetic equator, where linear growth appears to dominate, with nonlinear structures appearing at higher latitudes and higher frequencies. We investigate linear growth rate using the Waves in a Homogeneous, Anisotropic, Multi-component Plasma dispersion solver and locally observed electron phase space density measurements from the Electron Spectrometer sensor of the Cassini Plasma Spectrometer Investigation to determine the parameters responsible for the variation in chorus intensity and bandwidth. We find that a temperature anisotropy (T⊥/T∥ ~ 1.3) can account for linear spatiotemporal growth rate of whistler mode waves, which provides a majority of the observed frequency-integrated power. At the highest frequencies, intense, nonlinear, frequency-drifting structures (drift rates ~ 200 Hz/s) are observed a few degrees away from the equator and can account for a significant fraction of the total power. Chorus emission at higher frequencies is distinct from lower frequency whistler mode emission and is sometimes correlated with simultaneously observed low-frequency electromagnetic ion cyclotron waves. These electromagnetic ion cyclotron waves appear to modulate a slow frequency drift (~15 Hz/s) which develops into nonlinear growth with much larger frequency drift associated only with the higher-frequency chorus.

Journal ArticleDOI
TL;DR: An on-chip frequency reference is designed for low-power, low-cost, and fully integrated system-on-chip designs and pseudodifferential architecture is used to eliminate frequency variation caused by bias current and interleaving capacitors are implemented to extend its discharge time.
Abstract: An on-chip frequency reference is designed for low-power, low-cost, and fully integrated system-on-chip designs. In this relaxation oscillator, pseudodifferential architecture is used to eliminate frequency variation caused by bias current, and interleaving capacitors are implemented to extend its discharge time. A low-leakage programmable switch array (PSA) trimming method is proposed to calibrate the first- and second-order temperature coefficients (TCs) of the composite resistor. The oscillator was fabricated in a 0.35-μm 2P4M CMOS process with an area of 0.162 mm2. The oscillator operates at 130 kHz, and measurement results show that it achieves a frequency variation of less than ±0.5% over a temperature range of -20 °C-100°C and less than ±0.4% over a supply voltage range of 1-3 V.

Journal ArticleDOI
TL;DR: In this article, the power to frequency conversion in the resonant mode of a cryogenic sapphire loaded cavity resonator was investigated and it was shown that changes in radiation pressure and temperature in the dielectric contribute to a shift in the resonance frequency.
Abstract: We report on the measurement and characterization of power to frequency conversion in the resonant mode of a cryogenic sapphire loaded cavity resonator, which is used as the frequency discriminating element of a loop oscillator circuit. Fluctuations of power incident on the resonator lead to changes in radiation pressure and temperature in the sapphire dielectric, both of which contribute to a shift in the resonance frequency. We measure a modulation and temperature independent radiation pressure induced power to frequency sensitivity of −0.15 Hz/mW and find that this is the primary factor limiting the stability of the resonator frequency.

Proceedings ArticleDOI
11 Nov 2013
TL;DR: A differential Colpitts oscillator using AlN MEMS CMR designed in 0.13 um CMOS is presented in this work and current-based temperature compensation was employed to reduce oscillator drift across temperature.
Abstract: A differential Colpitts oscillator using AlN MEMS CMR designed in 0.13 um CMOS is presented in this work. The oscillator operates at 1.16 GHz, with a total power consumption of 4.2 mW at 1 V supply. It achieves a phase noise of -143.6 dBc/Hz, -173.3 dBc/Hz at 100 kHz and 1 MHz offset frequency respectively with a figure of merit (FOM) of 228.3 dB. Current-based temperature compensation was employed to reduce oscillator drift across temperature.

Journal ArticleDOI
TL;DR: A fully integrated 52 MHz frequency reference, designed in a 0.35 μm CMOS process, achieves 1.7 ppm frequency temperature accuracy within 0 to 80°C using a nonlinear compensation technique.
Abstract: A fully integrated 52 MHz frequency reference, designed in a 0.35 μm CMOS process, achieves 1.7 ppm frequency temperature accuracy within 0 to 80°C using a nonlinear compensation technique. The proposed low TCf0 reference oscillator achieves the lowest reported uncompensated temperature coefficient, i.e., 65.25 ppm/°C, among the integrated frequency references. The output reference frequency is obtained by dividing the differential LC Colpitts oscillator output operating at 1.6 GHz. Oscillator core dissipates 14 mW from 2.5 V. The blocks related to the temperature compensation scheme and the remaining system blocks consume 3 mW and 165 mW from 3.3 V supply, respectively. The measured phase noise of 52 MHz output is -94 dBc/Hz at 10 kHz offset frequency and rms period jitter is 3.2 ps.

Journal ArticleDOI
TL;DR: The current status of an Yb optical lattice clock at the Korea Research Institute of Standards and Science (KRISS) is reported in this article, where the long-term frequency drift showed only a linear dependence on time, confirming that the super-cavity was maintained a zero coefficient of thermal expansion.
Abstract: The current status of an Yb optical lattice clock at the Korea Research Institute of Standards and Science (KRISS) is reported. The systematic uncertainty of the Yb clock in the first accuracy evaluation was 1.5 × 10−14 [Park et al., Metrologia 50, 119 (2013)]. The uncertainty was dominated by the large uncertainties in the lattice ac Stark shift and the collisional shift, which were mainly limited by the large linewidth and jitter of the clock laser. Recently, a highly stable clock laser at 578 nm was developed with a short-term linewidth of 3.5 Hz and a frequency jitter of about 25 Hz at 1 s and 10 s measurement times, respectively. The long-term frequency drift showed only a linear dependence on time, confirming that the temperature of the super-cavity was maintained a zero coefficient of thermal expansion. The frequency of the lattice laser at 759 nm was phase locked to the optical frequency comb and could be stabilized at the “absolute” frequency of the “magic wavelength”, to within a 1-MHz uncertainty. This improvement greatly reduced the fractional uncertainty due to the lattice ac Stark shift down to 2 × 10−16. The systematic uncertainty of the clock is currently 5.3 × 10−15 and is dominated by the collisional frequency shift.

Journal ArticleDOI
TL;DR: The quantum nature of the Josephson synthesizer ensures very stable amplitudes and no frequency drift, together with the ability to synthesize arbitrary waveforms, can make this synthesizer a relevant tool for characterizing precision electronics and ac voltage metrology.
Abstract: We present the combination of two Josephson waveform synthesizers to generate waveforms with low harmonic distortion [below $-$ 110 dBc (carrier)] and amplitudes above the 1-V level. Fast and flexible code programming enables pulse-driven Josephson arrays to synthesize arbitrary waveforms. We have used the pulse-driven system to cancel the harmonic content from the binary array that can reach 1-V amplitudes. The quantum nature of the Josephson synthesizer ensures very stable amplitudes (better than $6 \times 10^{-8}$ ) and no frequency drift. This performance, together with the ability to synthesize arbitrary waveforms, can make this synthesizer a relevant tool for characterizing precision electronics and ac voltage metrology.

Patent
03 Dec 2013
TL;DR: In this paper, a generator and a method for tuning the generator are disclosed, which includes setting the frequency of the generator to a current best frequency and sensing a characteristic of the power applied by the generator.
Abstract: A generator and method for tuning the generator are disclosed. The method includes setting the frequency of power applied by the generator to a current best frequency and sensing a characteristic of the power applied by the generator. A current best error based upon the characteristic of the power is determined, and the frequency of the power at the current best frequency is maintained for a main-time-period. The frequency of the power is then changed to a probe frequency and maintained at the probe frequency for a probe-time-period, which is less than the main-time-period. The current best frequency is set to the probe frequency if the error at the probe frequency is less than the error at the current best frequency.

Journal ArticleDOI
TL;DR: In this paper, an electrostatic-driving and capacitive-detection differential resonant pressure microsensor has been proposed for pressure monitoring in various locations including weather stations and aerospace.
Abstract: Presented is the design, fabrication and characterisation of an electrostatic-driving and capacitive-detection differential resonant pressure microsensor. The differential structure consists of two resonators immobilised on the diaphragm. In response to the pressure under measurement, the diaphragm deflection increases the intrinsic resonant frequency of one resonant beam and decreases the resonant frequency of the other. A differential frequency output reduces the common frequency drift caused by stresses and interferences, and thus improves the sensor's stability. The device geometries were optimised using numerical simulations and the fabrication process was based on a silicon-on-insulator wafer requiring only two masks with simplified microfabrication steps (e.g. sputter, wet etching and deep reactive ion etching). The sensor was quantified in an open-loop characterisation platform, producing a quality factor higher than 10 430 in vacuum ( < 0.5 Pa). Closed-loop test results recorded a linear resonant frequency shift (a linear correlation of 0.9999) in response to applied pressure, with a sensitivity of 227 Hz/kPa. This resonant pressure microsensor has a simple fabrication process and reliable performance, and can be used for pressure monitoring in various locations including weather stations and aerospace.

Patent
12 Mar 2013
TL;DR: In this article, the fabrication guidelines of integrated optoelectronic oscillators with frequency and phase stability, having higher frequency selectivity in a relatively small size (compared to the larger size of a higher order electrically realized RF filter), reduced temperature sensitivity, and minimized frequency drift are presented.
Abstract: The present invention details fabrication guidelines of integrated optoelectronic oscillators with frequency and phase stability, having higher frequency selectivity in a relatively small size (compared to the larger size of a higher order electrically realized RF filter), reduced temperature sensitivity, and minimized frequency drift. The integrated photonic components and RF oscillator may use Silicon photonics and microelectronic integration using CMOS and BiCMOS technology, eliminating the need for bulky and/or discrete optical and microwave components.

Patent
Yu-Tso Lin1
22 Feb 2013
TL;DR: In this article, the frequency range setting of a voltage controlled oscillator is set to an inverted digital value of the first digital value for a second output frequency, based on the first difference between a reference frequency and a feedback frequency resulting from the first output frequency.
Abstract: A method for self-calibrating a phase locked loop (PLL) includes setting a frequency range setting of a voltage controlled oscillator (VCO) to a first digital value for a first output frequency. A first difference is measured between a reference frequency and a feedback frequency resulting from the first output frequency. The frequency range setting is set to an inverted digital value of the first digital value for a second output frequency. A second difference is measured between the reference frequency and the feedback frequency resulting from the second output frequency. A value of the frequency range setting is selected based on the first difference and the second difference.

Proceedings ArticleDOI
16 Jun 2013
TL;DR: In this article, a low phase-noise 4.9 MHz oscillator using a fused silica micro-mechanical resonator is reported, achieving high quality factor (Q ~15,860) and low motional impedance (Rm ~360 Ω).
Abstract: In this paper, we report on a low phase-noise 4.9 MHz oscillator using a fused silica micro-mechanical resonator. The resonator is implemented using a piezoelectric-on-silica structure, achieving high quality factor (Q ~15,860) and low motional impedance (Rm ~360 Ω). By interfacing the resonator to a CMOS amplifier, an oscillator phase noise of -138 dBc/Hz at 1 kHz, -154 dBc/Hz at 10 kHz, and -155 dBc/Hz at far-from-carrier offset frequencies has been achieved at a low-supply voltage. Vibration tests on the oscillator indicate an acceleration sensitivity of less than 4 ppb/g. The frequency tuning properties of the silica oscillator are also characterized for compensating frequency variations due to environmental effects.

Proceedings ArticleDOI
17 Apr 2013
TL;DR: In this article, the authors present an ultra-low power, low-phase noise, and small-size voltage-controlled ring oscillator for use in implantable electronics operating in the Medical Implant Communication Service (MICS) frequency band and 65-nm IBM CMOS technology.
Abstract: This study presents an ultra-low-power, low-phase noise, and small-size voltage-controlled ring oscillator for use in implantable electronics operating in the Medical Implant Communication Service (MICS) frequency band and 65-nm IBM CMOS technology. This five-stage voltage-controlled ring oscillator does not require external inductor and capacitor similar to other LC oscillators, and hence, requires very small die area. A new methodology to design them has been employed in this study, and for optimizing the design of this voltage-controlled oscillator (VCO), the phase noise and power consumption of five-stage ring oscillators have been formulated and simulated for different sizes of transistors. The simulated phase noise of this VCO was -111 dBc/Hz at 1 MHz offset from a 400-MHz center frequency. The power consumption of VCO was 158 μW. This VCO has a tuning range from 352 to 454 MHz for tuning within the MICS band frequency, and frequency correction accounts for process supply voltage and temperature effects.


Proceedings ArticleDOI
19 May 2013
TL;DR: A voltage controlled MEMS oscillator (VCMO) fabricated in 65nm CMOS process, resulting in a power consumption of 47μW measured under a 0.55V power supply, which is the lowest reported in literature for an application in the 200MHz range.
Abstract: A voltage controlled MEMS oscillator (VCMO) fabricated in 65nm CMOS process is proposed in this paper. The piezoelectric aluminum nitride (AlN) Contour-Mode MEMS resonator based oscillator can be operated under multiple frequencies from 204MHz, to 517MHz, to 850MHz. A maximum overall tuning range of 611ppm is achieved at a center frequency of 204MHz. The proposed oscillator operates in the sub-threshold region, resulting in a power consumption of 47μW measured under a 0.55V power supply, which is the lowest reported in literature for an application in the 200MHz range. The measured oscillator phase noise is -77dBc/Hz at 1kHz offset from the 204MHz carrier.

Journal ArticleDOI
TL;DR: In this article, a CML ring oscillator with two frequency triplers for quadrature localoscillator generation is presented, which achieves an output frequency of 16.56 to 19.8 GHz (17.8%) at a Vtune of 0 to 1.2 V.
Abstract: This letter presents a current-mode-logic (CML) ring oscillator integrated with two frequency triplers for quadrature local-oscillator generation. Quadrature signals and frequency-doubled signals of the CML ring oscillator are propagated to drive two single-balanced mixers for up-converting the frequency by triple and achieving quadrature output and low power consumption. Fabricated by a TSMC 90 nm CMOS technology, the proposed circuit consumed 8.7 mW dc power at a 1.2 V supply voltage and achieved an output frequency of 16.56 to 19.8 GHz (17.8%) at a Vtune of 0 to 1.2 V. The phase noise of - 104.6 dBc/Hz was measured from the output signal at a 1 MHz offset frequency. A remarkable figure of merit with a tuning range evaluated at - 188.4 was also obtained.