Oscillator Phase Noise Research Articles

Experimental study on electromechanical performance decoupling and vibration suppression of crystal oscillator

In the mechanical vibration environment, the phase noise of crystal oscillator would deteriorate sharply, which would lead to the decline of the stability of crystal oscillator and affect the comprehensive performance of the whole electronic equipment. In this paper, the mechanism of electromechanical coupling between mechanical vibration and phase noise is analysed theoretically. The relationship between phase noise and vibration magnitude and the sensitivity of phase noise to different vibration frequencies and directions are studied experimentally, then the decoupling of mechanical performance and electrical performance is realized. Based on this, a vibration isolator for crystal oscillator is designed, which can achieve 15-2000Hz full frequency band random vibration attenuation, the vibration acceleration RMS value is reduced by 95%, and the phase noise degradation of crystal oscillator is less than 5dB. The research has a certain reference value for the vibration isolation design of electromechanical coupling vibration sensitive devices.

Mitigation of noise in Josephson parametric oscillator by injection locking

Injection locking is a well-established technique widely used in optics as well as solid-state devices for efficient suppression of noise. We present the spectroscopic characterization of the effect of the injection-locking signal (ILS) in mitigating the phase noise of a Josephson parametric oscillator, whose output oscillating phase undergoes indeterministic switching between the bistable states with symmetry θ→θ+π. With the injection of a weak locking signal, we measure the phase noise power spectral density of the self-sustained oscillator output state for different locking signal strengths. We observed suppression of phase noise by injection locking. As the ILS strength surpasses more than a few photons, the output state stays completely pinned to the locking phase of the ILS, and the random telegraphic noise due to switching of the states is significantly suppressed.

1/f Additive Phase Noise Analysis for One-Port Injection-Locked Oscillators

The 1/f additive phase noise of one-port injection-locked oscillators is experimentally characterized and analyzed using a simple analytic model based on the generalized 1/f Kurokawa theory. To experimentally verify the prediction of the simple analytic model proposed, two negative-conductance transmission line pHEMT oscillators operating at 2.4828 GHz and 2.485 GHz were designed and fabricated. A new configuration for integrating an additive phase noise measurement system with a large signal network analyzer (LSNA) is introduced to jointly acquire both the noise and RF waveforms of the one-port injection-locked oscillator. The Kurokawa derivatives needed for the analytic expression were experimentally obtained using the LSNA measurements and optimized to accurately model the corner frequency. A good agreement between the predicted and experimental results was obtained for both the injection-locked and free-running oscillators. In contrast to phase noise measurements of the free-running oscillator, which can only characterize the oscillator-upconverted 1/f3 noise, the additive phase noise characterization of the injection-locked oscillator is shown to provide the means to directly observe and characterize the input-referred intrinsic 1/f noise source of the oscillator negative resistance.

Modeling the Effects of Oscillator Phase Noise and Synchronization on Multistatic SAR Tomography

Recent results have highlighted the potential ability of bi- and multistatic synthetic aperture radar (SAR) tomographers to measure vegetation structure and surface topography. However, the quality of SAR tomographic measurements with multiple platforms is impacted by the phase instability in each platform’s oscillator. The phase noise, if uncompensated, may lead to degradation in the SAR data products such as increased sidelobe levels, reduced peak amplitude of the impulse response, and a low frequency phase modulation, among others. In this work, we model and examine the effects of oscillator phase noise on tomographic SAR signals for spaceborne missions flying in formation. A synchronization process is also adopted to help mitigate oscillator phase errors by measuring and predicting relative phase offsets at prescribed temporal intervals. A simulation tool was developed to examine the point target response as seen by realistic satellite constellations in low Earth orbit using different quality oscillators, radar configurations, and synchronization configurations. A first analysis of a multi-platform tomographic SAR mission suggests that a system without a dedicated physical link with minimal effects on the point target response may be achievable using current oscillators. Our analysis also shows that phase noise has differing effects on multistatic radar modes. Tomograms formed with a system operating in SIMO mode are the most affected by oscillator phase noise error, followed by MIMO, with negligible effects on the SAR-SISO mode. These trade studies and the simulation tool can be used to help inform the design of future multistatic radar missions.

Multiuser-MISO Precoding Under Channel Phase Uncertainty in Satellite Communication Systems

Linear and symbol-level precoding in satellite communications have received increasing research attention thanks to their ability to tackle inter-beam interference, allowing the use of spectral resources more efficiently. However, there are still challenges and open questions regarding the implementation of practical precoding systems taking the phase uncertainties in estimating the channel state information into account. This work assesses the impact of phase variations and uncertainties inherent to the satellite communication system operating a precoded forward link. Specifically, we address the inability to measure at the user terminal, the absolute phase rotation introduced by the channel, and the transponder local oscillator phase noise effects on the precoding operations considering the use of frequency division multiplexing in the forward-uplink transmission. We formally demonstrate that the system performance for linear and non-linear precoding operations is not affected by the uncertainty in the phase measurements at the user terminal. Additionally, we show that using a single frequency reference for all the local oscillators at the transponder does not avoid the phase variations related to the frequency division multiplexing in the forward-uplink. This work demonstrates that these phase variations would not affect the system performance for an ideal zero-delay precoding loop. However, this is not feasible in practical scenarios, where the phase noise of the frequency reference at the transponder and the loop delay determine the impact on the system performance. We validate our results by simulations considering three frequency references with different stability levels in a typical geosynchronous orbit (GEO) satellite system. Our results suggest that practical implementations of multiuser-MISO precoding systems must include a differential phase synchronization loop to compensate for this performance degradation.

A 0.49 mm2 CMOS Low-Power TVCO Achieving FoM of 190.36 dBc/Hz for 5G New Radio Application

This paper describes the implementation of low-power, low-phase-noise (PN), and robust startup tailless class-C voltage-controlled oscillator (TVCO) for 5G new radio (NR) technology. It features dual gate voltage control source biasing to generate fast startup and differential signal amplitude balancing, thus eliminating the requirement of the conventional tail current source, which introduces more parasitic capacitance that affects the oscillation frequency, phase noise, and power consumption. The TVCO is fabricated in 180 nm complementary metal-oxide semiconductor (CMOS) technology, oscillating at 2.59 GHz 5G NR carrier frequency with an output voltage swing of 1.7 V and low-phase-noise of -122 dBc/Hz at 1 MHz offset with supply voltage headroom of 0.7 V. Without additional features added, the TVCO consumes very low-power and a small die area of 0.98 mW and 0.49 mm2, respectively. The achieved figure of merit (FoM) is 190.36 dBc/Hz.

Table-Based Adaptive Digital Phase-Locked Loop for GNSS Receivers Operating in Moon Exploration Missions.

An adaptive digital phase-locked loop (DPLL) continually adjusts the noise bandwidth of the loop filter in global navigation satellite system (GNSS) receivers to track signals by measuring the signal-to-noise ratio and/or dynamic stress. Such DPLLs have a relatively large amount of computational complexity compared with the conventional DPLL. A table-based adaptive DPLL is proposed that adjusts the noise bandwidth value by extracting it from the pre-generated table without additional calculations. The values of the noise bandwidth table are computed in an optimal manner in consideration of the thermal noise, oscillator phase noise, and dynamic stress error. The calculation method of the proper integration time to maintain the stability of the loop filter is presented. Additionally, the simulation is configured using the trajectory analysis results from the Moon exploration mission and shows that the proposed algorithm operates stably in harsh environments, while a conventional fixed bandwidth loop cannot. The proposed algorithm has a similar phase jitter performance to the existing adaptive DPLL algorithms and has an execution time that is approximately 2.4-5.4 times faster. It is verified that the proposed algorithm is computationally efficient while maintaining jitter performance.

Giant injection-locking bandwidth of a self-pulsing limit-cycle in an optomechanical cavity

Locking of oscillators to ultra-stable external sources is of paramount importance for improving close-to-carrier phase noise in free running oscillators. In most of them, such as Micro-Electro-Mechanical-Systems or LC circuit-based oscillators, the locking frequency range is limited by the robustness of their natural frequency, which comes explicitly related with intrinsic parameters of the system. In this work we report the synchronization of an optically-driven self-pulsing limit-cycle taking place in a silicon optomechanical crystal cavity to an external harmonic signal that modulates the driving laser. Because of the extreme ductility of the natural self-pulsing frequency (several tens of MHz), the injection-locking mechanism is highly efficient and displays giant relative bandwidths exceeding 60%. The external modulation reveals itself as a knob to explore dynamical attractors that are otherwise elusive and, in particular, as a means to initialize a mechanical resonator into a state of self-sustained oscillations driven by radiation pressure forces. Moreover, we exploit the large anharmonicity of the studied limit-cycle to induce injection-locking to integer multiples and fractions of the frequency of the external reference, which can be used for frequency conversion purposes in nano-electro-opto-mechanical systems.

Phase Noise Modeling and Experimental Demonstration of Single and Dual-Loop Direct Modulation Optoelectronic Oscillator

A single and dual loop direct modulation Opto-Electronic Oscillator (DMOEO) phase noise model for generation of low phase noise signal operating in Radio Frequency (RF) and microwave frequency range is proposed and experimentally demonstrated. The distribute feedback (DFB) laser diode is used in the proposed design to perform the RF to optical conversion by exploiting its non-linear transfer function characteristics, in contrast to external modulator in conventional OEO designs. We presented the theoretical phase noise model for single and multi-loop DMOEO deign with all possible noise contributions. Also, simulation scenarios have been demonstrated to show the impact of different noise source on the overall phase noise performance of the OEO. A single and dual loop DMOEO with phase noise of −112 dBc/Hz and −110 dBc/Hz at 10 kHz offset from 2.4 GHz carrier respectively is designed and the side mode suppression better than 50 dB is achieved for the generated signal with 11 dBm output power.

Phase Noise Analysis of Resonator-Enhanced Electro-Optic Comb-Based Analog Coherent Receivers

We present an architecture for wavelength-division-multiplexed coherent data center links employing resonator-enhanced electro-optic frequency comb generators as both transmitter and local oscillator (LO) sources. We show that in each frequency comb, the phase noise in all comb lines is determined completely by the optical phase noise of the seed laser and the phase noise of the microwave oscillator. We propose an analog coherent receiver that performs carrier recovery on all wavelength channels using only two phase-locked loops. We use an independent cascade of phase shifters driven by marker tone detection in each channel for polarization recovery and compensation of a static optical phase shift. We study design examples for quadrature phase-shift keying and 16-ary quadrature amplitude modulation (16-QAM), determining requirements on the transmitter and LO seed laser linewidths and the LO frequency modulation (FM) response. We find that for a dual-polarization (DP) 16-QAM link with 17 wavelength channels, each operating at 56 GBaud, if the combined linewidth of the transmitter and LO seed lasers is 100 kHz, the LO seed laser requires an FM response that is flat from d.c. to several hundred MHz to maintain a phase-error penalty below 1 dB.

Local Oscillator Phase Noise Impact on M-ary Modulation Schemes

This paper presents the impact of a local oscillator phase noise on digital modulation schemes based on bit error rate and error vector magnitude. The adopted methodology enables base band metrics estimation which is dependent of a specific communication standard. A generic local oscillator phase noise model is presented to evaluate the impact of different phase noise values on error vector magnitude and bit error rate. For a phase noise of -65dBc @ 1kHz the error vector magnitude changes from 7% to 12.8%. Increasing the modulation order leads to bit error rate increment for the same phase noise value.

Analytic estimation of jitter and eye diagram based on transmission line time domain response considering skin effect and stochastic crosstalk

In this article, an analytic approach is proposed for estimation of oscillating signal jitter and eye diagram on a transmission line (TL). Basically, the jitter is a result of oscillator phase noise. There are two types of internal and external sources of phase noise which both are considered in the proposed stochastic estimation. Crosstalk between adjacent TLs is the main source of external phase noise on an oscillating signal of a system layout. This phenomenon on the victim TL is studied with stochastic input signal driving for the aggressor TL. For mathematical derivation, the skin effect of the TL is considered for better accuracy. The skin effect of the TL is considerable in high frequency like bit rate one. In addition, a magnetic near-field probe and test procedure are designed and proposed for the measurement of the TL operating stochastic signal without loading effect. A test board is designed and fabricated for verification of the proposed approach. The analytic derivations have good accuracy in estimation of bit rate of the TL less than 4% for the fabricated test board. For this test board, the crosstalk effect on the TL closes the eye diagram height by 30% in 20 GHz.

A Current Re-Use Quadrature RF Receiver Front-End for Low Power Applications: Blixator Circuit

This article presents the theory and implementation of a quadrature and differential RF front-end receiver. Combining balun, low-noise amplifier (LNA), mixer, and oscillator in a single stage, the proposed circuit, named the Blixator, is well suited for low-power applications. The baseband’s transimpedance amplifier (TIA) also shares part of its dc current with the Blixator cell, resulting in sub-milliwatt power consumption. To avoid additional power and area by quadrature LO generation, the I/Q signals are generated at RF, employing the inductors already required for providing the dc current path of the LNA transistors. The expressions for gain, noise figure (NF), and phase noise of the voltage-controlled oscillator (VCO) are derived, and the behavior of the circuit is thoroughly investigated. The prototype of the Blixator receiver is implemented in a 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS technology. The experimental results show a NF of 10.5 dB, an IIP3 of −15.5 dBm, at the maximum gain, and an image rejection of 23 dB, which meets the requirements for the Bluetooth Low Energy (BLE) standard. The circuit consumes only 340- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> , from a 0.8-V supply, and its die area is 0.75 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

A 56-Gb/s 8-mW PAM4 CDR/DMUX With High Jitter Tolerance

The demand for low-power wireline circuits has motivated extensive work on novel circuit solutions. This article describes a one-eighth-rate clock and data recovery (CDR) circuit and a demultiplexer (DMUX) for processing four-level pulse-amplitude modulation (PAM4) signals in receivers (RXs). Detecting both major and minor data transitions, the proposed architecture can achieve a wider loop bandwidth (BW), suppressing oscillator phase noise and improving the jitter tolerance. Fabricated in 28-nm CMOS technology, the prototype provides a jitter transfer BW of 160 MHz with a tolerance of 1 UI at 10 MHz.

Design of a 1.29–1.61GHz LC-VCO with Improved Phase Noise and Figure-of-Merit (FoMT) for GPS and Satellite Navigation

This paper demonstrates a low-phase noise and high FoMT differential CMOS LC-VCO working at 1.29–1.61[Formula: see text]GHz. An RC filter tail current source is used in this design to reduce the second-harmonic oscillation phase noise. The VCO is implemented in 180[Formula: see text]nm process technology. The post-layout simulation results indicate that this proposed VCO operates faithfully in the 1.29–1.61[Formula: see text]GHz band with a frequency tuning range (FTR) of 320[Formula: see text]MHz. By using inversion mode N-MOSFET varactor, the designed VCO obtains 22.06% FTR. The phase noise of the VCO is [Formula: see text]130.21[Formula: see text]dBc/Hz at 1[Formula: see text]MHz offset frequency. It consumes 4.01[Formula: see text]mW average power from 1.3[Formula: see text]V supply. The cell area occupied by the design is [Formula: see text]. Figure-of-merit considering FTR (FoM[Formula: see text] is [Formula: see text]194.14[Formula: see text]dBc/Hz at 1[Formula: see text]MHz offset frequency, phase noise and average power consumption. The proposed VCO can be used for low-phase noise GPS and satellite navigation.

Ultra low phase noise and high output power monolithic microwave integrated circuit oscillator for 5G applications

novel structure of low phase noise and high output power monolithic microwave integrated circuit (MMIC) oscillator is presented in order to use it in 5G applications. The oscillator is based on the ED02AH process which allows us to design a microwave oscillator keeping a minimum size which is impossible to have it using other technologies since microwave oscillators are sensitive components above 20 GHz. The oscillator is studied, designed, and optimized on a GaAs substrate from the OMMIC foundry using the advanced design system (ADS) simulator in order to obtain a miniaturized oscillator (1.1×1.3 mm&lt;sup&gt;2&lt;/sup&gt;) generating two signals of different frequencies f&lt;sub&gt;o1&lt;/sub&gt;=26 GHz and f&lt;sub&gt;o2&lt;/sub&gt;=30 GHz. The objective is to design an oscillator with high output power and low phase noise while respecting its specifications. The optimization of the proposed microwave oscillator shows satisfying results. Indeed, at 26 GHz and 30 GHz, the output powers are respectively 13.33 dBm and 14.89 dBm. The oscillator produces a sinusoidal signal of 1.5 V and 1.75 V amplitude respectively at 26 GHz and 30 GHz. The oscillator phase noise at f&lt;sub&gt;o1&lt;/sub&gt; and f&lt;sub&gt;o2&lt;/sub&gt; resonance frequencies using the liquid crystal (LC) resonator shows respectively -109 dBc/Hz and -110 dBc/Hz at 10 MHz offset.

Design and Analysis of MIMO Systems Using Energy Detectors for Sub-THz Applications

The significant amount of unused spectrum in sub-TeraHertz frequencies is contemplated to realize high rate wireless communications for beyond 5G networks. Yet, the performance of radio-frequency sub-TeraHertz systems is severely degraded by strong oscillator phase noise. Therefore, we investigate in this paper the use of multiple-input multiple-output (MIMO) systems with energy detection receivers to achieve high rate communications robust to phase noise. First, the design of the receiver detection algorithm is addressed. Two detectors are proposed for the studied nonlinear MIMO channel, either derived from the maximum likelihood decision rule by using a Gaussian approximation, or based on the use of neural networks. Second, the communication performance is assessed through numerical simulations for uncoded and coded systems. We consider a realistic scenario modeling an indoor wireless link in D-band with directive antennas and strongly correlated line-of-sight channels. Our results demonstrate that spatial multiplexing with non-coherent sub-TeraHertz transceivers can be realized on strongly correlated line-of-sight channels using the proposed detection schemes. Thereby, we highlight that high-rate radio-frequency sub-TeraHertz systems can be implemented with low-complexity and low-power architectures using MIMO systems with energy detection receivers.

Chronic Fatigue Syndrome: A Quantum Mechanical Perspective

Chronic Fatigue Syndrome: A Quantum Mechanical Perspective

A 40 GHz CMOS PLL With −75-dBc Reference Spur and 121.9-fsrms Jitter Featuring a Quadrature Sampling Phase-Frequency Detector

The high phase noise (PN) of CMOS millimeter-wave oscillators has encouraged the adoption of wide loop bandwidth for an integer- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> phase-locked loop (PLL). This article proposes a quadrature sampling phase-frequency detector (QS-PFD) to disengage the tradeoff between spur rejection and loop bandwidth. With the introduction of an auxiliary path for phase detection, the spur generated by the main path is canceled without incurring extra power or degrading the loop stability. The high gain of the QS-PFD attenuates its jitter contribution to the loop. The QS-PFD enables fast frequency detection and lock detection. Implemented in 40-nm CMOS technology, the proposed PLL shows a −75-dBc reference spur, −101.5-dBc/Hz PN at a 1-MHz offset, and a minimum integrated jitter of 121.9 fs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> (10 kHz–100 MHz) at 38.2 GHz with a division ratio of 128. The lock detection time is at the microsecond level. The proposed PLL consumes 23.6 mW from a 1.1-V power supply, leading to a figure of merit (FoM) of −245 dB.

1/f² Phase Noise Analysis in Active-Coupling LC-Tank Oscillators With Frequency Mismatch

Multi-core LC-tank oscillators have attracted a great deal of attention since their capability to achieve ultra-low phase noise in a scalable and power-efficient way. This brief presents a study of 1/f <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> phase noise in active-coupling oscillators. A complete frequency domain analysis is proposed to describe the steady-state oscillators amplitude and phase. Closed-form formulas are derived for phase noise degradation caused by resonance frequency mismatches between the LC-tanks. The theoretical analysis is first validated through extensive simulations and then exploited to compare the robustness to LC-tank frequency mismatches in active- and resistive-coupling oscillators, proving the superior performance of the latter.