Showing papers on "Phase noise published in 2015"
TL;DR: This work demonstrates a miniature 10 GHz radio frequency photonic oscillator characterized with phase noise better than −60 dBc Hz−1 at 10GHz, −90 dBcHz+1 at 100MHz, and −170dBC Frequency Stability, at the level of 10−10 at 1–100s integration time.
Abstract: Femtosecond laser-based generation of radio frequency signals has produced astonishing improvements in achievable spectral purity, one of the basic features characterizing the performance of an radio frequency oscillator. Kerr frequency combs hold promise for transforming these lab-scale oscillators to chip-scale level. In this work we demonstrate a miniature 10 GHz radio frequency photonic oscillator characterized with phase noise better than -60 dBc Hz(-1) at 10 Hz, -90 dBc Hz(-1) at 100 Hz and -170 dBc Hz(-1) at 10 MHz. The frequency stability of this device, as represented by Allan deviation measurements, is at the level of 10(-10) at 1-100 s integration time-orders of magnitude better than existing radio frequency photonic devices of similar size, weight and power consumption.
468 citations
TL;DR: In this paper, the authors proposed a digital self-interference cancellation technique for full-duplex systems, which is shown to significantly mitigate the selfinterference signal as well as the associated transmitter and receiver impairments, more specifically, transceiver nonlinearities and phase noise.
Abstract: Full-duplex systems are expected to double the spectral efficiency compared to conventional half-duplex systems if the self-interference signal can be significantly mitigated. Digital cancellation is one of the lowest complexity self-interference cancellation techniques in full-duplex systems. However, its mitigation capability is very limited, mainly due to transmitter and receiver circuit's impairments (e.g., phase noise, nonlinear distortion, and quantization noise). In this paper, we propose a novel digital self-interference cancellation technique for full-duplex systems. The proposed technique is shown to significantly mitigate the self-interference signal as well as the associated transmitter and receiver impairments, more specifically, transceiver nonlinearities and phase noise. In the proposed technique, an auxiliary receiver chain is used to obtain a digital-domain copy of the transmitted Radio Frequency (RF) self-interference signal. The self-interference copy is then used in the digital-domain to cancel out both the self-interference signal and the associated transmitter impairments. Furthermore, to alleviate the receiver phase noise effect, a common oscillator is shared between the auxiliary and ordinary receiver chains. A thorough analytical and numerical analysis for the effect of the transmitter and receiver impairments on the cancellation capability of the proposed technique is presented. Finally, the overall performance is numerically investigated showing that using the proposed technique, the self-interference signal could be mitigated to $\sim$ 3 dB higher than the receiver noise floor, which results in up to 76% rate improvement compared to conventional half-duplex systems at 20 dBm transmit power values.
343 citations
TL;DR: This work uses a "locally" generated LO and implements with a 1-GHz shot-noise-limited homodyne detector to achieve high-speed quantum measurement, and proposes a secure phase compensation scheme to maintain a low level of excess noise.
Abstract: We report a 100-MHz continuous-variable quantum key distribution (CV-QKD) experiment over a 25-km fiber channel without sending a local oscillator (LO). We use a "locally" generated LO and implement with a 1-GHz shot-noise-limited homodyne detector to achieve high-speed quantum measurement, and we propose a secure phase compensation scheme to maintain a low level of excess noise. These make high-bit-rate CV-QKD significantly simpler for larger transmission distances compared with previous schemes in which both LO and quantum signals are transmitted through the insecure quantum channel.
213 citations
TL;DR: In this paper, the authors proposed and demonstrated a pilot-aided feedforward data recovery scheme which enables reliable coherent detection using a locally generated oscillator (LO) for continuous-variable quantum key distribution (CV-QKD).
Abstract: Continuous-variable quantum key distribution (CV-QKD) protocols based on coherent detection have been studied extensively in both theory and experiment. In all the existing implementations of CV-QKD, both the quantum signal and the local oscillator (LO) are generated from the same laser and propagate through the insecure quantum channel. This arrangement may open security loopholes and also limit the potential applications of CV-QKD. In this paper, we propose and demonstrate a pilot-aided feedforward data recovery scheme which enables reliable coherent detection using a \locally" generated LO. Using two independent commercial laser sources and a spool of 25 km optical ber, we construct a coherent communication system. The variance of the phase noise introduced by the proposed scheme is measured to be 0:04 (rad 2 ), which is small enough to enable secure key distribution. This technology also opens the door for other quantum communication protocols, such as the recently proposed measurement-device-independent (MDI) CV-QKD where independent light sources are employed by dierent users.
208 citations
TL;DR: This work considers two distinct operation modes, namely, when the phase noise processes at the M BS antennas are identical and when they are independent (nonsynchronous operation), and derives a lower bound on the sum-capacity, and compares their performance.
Abstract: Multiuser multiple-input–multiple-output (MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information. In particular, we consider two distinct operation modes, namely, when the phase noise processes at the $M$ BS antennas are identical (synchronous operation) and when they are independent (nonsynchronous operation) . We analyze a linear and low-complexity time-reversal maximum-ratio combining reception strategy. For both operation modes, we derive a lower bound on the sum-capacity, and we compare their performance. Based on the derived achievable sum-rates, we show that with the proposed receive processing, an $O(\sqrt{M} ) $ array gain is achievable. Due to the phase noise drift, the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users.
190 citations
TL;DR: This work demonstrates synchronization in arrays of silicon nitride micromechanical oscillators coupled in an all-to-all configuration purely through an optical radiation field and shows that the phase noise of the synchronized oscillators can be improved by almost 10 dB below the phase Noise limit for each individual oscillator.
Abstract: Synchronization of many coupled oscillators is widely found in nature and has the potential to revolutionize timing technologies. Here, we demonstrate synchronization in arrays of silicon nitride micromechanical oscillators coupled in an all-to-all configuration purely through an optical radiation field. We show that the phase noise of the synchronized oscillators can be improved by almost 10 dB below the phase noise limit for each individual oscillator. These results open a practical route towards synchronized oscillator networks.
178 citations
TL;DR: The proposed digital architecture adopts a narrow range low-power time-amplifier based TDC (TA-TDC) to achieve sub 1 ps resolution and is less susceptible to DTC nonlinearity and has faster settling and tracking behavior compared to a BB-PLL.
Abstract: A digital fractional-N PLL that employs a high resolution TDC and a truly $\Delta \Sigma$ fractional divider to achieve low in-band noise with a wide bandwidth is presented. The fractional divider employs a digital-to-time converter (DTC) to cancel out $\Delta \Sigma$ quantization noise in time domain, thus alleviating TDC dynamic range requirements. The proposed digital architecture adopts a narrow range low-power time-amplifier based TDC (TA-TDC) to achieve sub 1 ps resolution. By using TA-TDC in place of a BBPD, the limit cycle behavior that plagues BB-PLLs is greatly suppressed by the TA-TDC, thus permitting wide PLL bandwidth. The proposed architecture is also less susceptible to DTC nonlinearity and has faster settling and tracking behavior compared to a BB-PLL. Fabricated in 65 nm CMOS process, the prototype PLL achieves better than ${-}$ 106 dBc/Hz in-band noise and 3 MHz PLL bandwidth at 4.5 GHz output frequency using 50 MHz reference. The PLL consumes 3.7 mW and achieves better than 490 fs $ _{{\rm rms}}$ integrated jitter. This translates to a FoM $ _{{\rm J}}$ of ${-}$ 240.5 dB, which is the best among the reported fractional-N PLLs.
119 citations
TL;DR: By increasing frequency sweeping speed, the influence of environmental phase disturbance on TGD-OFDR is mitigated significantly, which makes phase extraction in this new scheme more reliable than that in conventional OFDR-based method, leading to the realization of long distance quantitative vibration measurement.
Abstract: A novel distributed fiber vibration sensing technique based on phase extraction from time-gated digital optical frequency domain reflectometry (TGD-OFDR) which can achieve quantitative vibration measurement with high spatial resolution and long measurement range is proposed. A 90 degree optical hybrid is used to extract phase information. By increasing frequency sweeping speed, the influence of environmental phase disturbance on TGD-OFDR is mitigated significantly, which makes phase extraction in our new scheme more reliable than that in conventional OFDR-based method, leading to the realization of long distance quantitative vibration measurement. By using the proposed technique, a distributed vibration sensor that has a measurement range of 40 km, a spatial resolution of 3.5 m, a measurable vibration frequency up to 600 Hz, and a minimal measurable vibration acceleration of 0.08g is demonstrated.
108 citations
TL;DR: A laser phase and frequency noise measurement method by an unbalanced Michelson interferometer composed of a 3 × 3 optical fiber coupler is proposed and obtains the noise features of a narrow linewidth laser conveniently without any specific assumptions or noise models.
Abstract: A laser phase and frequency noise measurement method by an unbalanced Michelson interferometer composed of a 3 × 3 optical fiber coupler is proposed. The relations and differences of the power spectral density (PSD) of differential phase and frequency fluctuation, PSD of instantaneous phase and frequency fluctuation, phase noise and linewidth are derived strictly and discussed carefully. The method obtains the noise features of a narrow linewidth laser conveniently without any specific assumptions or noise models. The technique is also used to characterize the noise features of a narrow linewidth external-cavity semiconductor laser, which confirms the correction and robustness of the method.
103 citations
TL;DR: This paper describes a fractional-N subsampling PLL in 28 nm CMOS made possible with almost no penalty in phase noise performance thanks to the use of a 10 bit, 0.55 ps/LSB digital-to-time converter circuit operating on the sampling clock.
Abstract: This paper describes a fractional-N subsampling PLL in 28 nm CMOS. Fractional phase lock is made possible with almost no penalty in phase noise performance thanks to the use of a 10 bit, 0.55 ps/LSB digital-to-time converter (DTC) circuit operating on the sampling clock. The performance limitations of a practical DTC implementation are considered, and techniques for minimizing these limitations are presented. For example, background calibration guarantees appropriate DTC gain, reducing spurs. Operating at 10 GHz the system achieves −38 dBc of integrated phase noise (280 fs RMS jitter) when a worst case fractional spur of −43 dBc is present. In-band phase noise is at the level of −104 dBc/Hz. The class-B VCO can be tuned from 9.2 GHz to 12.7 GHz (32%). The total power consumption of the synthesizer, including the VCO, is 13 mW from 0.9 V and 1.8 V supplies.
103 citations
TL;DR: This chip presents the first fully integrated terahertz phased array on silicon and the output power is higher than any lens-less silicon-based source above 200 GHz and the phase noise is lower than all silicon radiating sources above 100 GHz.
Abstract: This work introduces a 2-D phased array architecture that is suitable for high power radiation at mm-Wave and Terahertz frequencies. We address the challenge of signal generation above the cut-off frequency of transistors by presenting a radiation method based on the collective performance of a large number of synchronized sources. As theory shows, both frequency locking/tuning and beam steering can be independently achieved by manipulating the local coupling between the nearest neighbors. This control method results in a dynamical network that is insensitive to array dimensions and is scalable to the point that can achieve a level of output power and spectral purity beyond the reach of conventional sources. To demonstrate the concept, we implement a 4 $\times$ 4 version of this phased array at 340 GHz using a 65 nm bulk CMOS process. The paper presents the design and implementation of the oscillators, couplings and the integrated antennas. The measured results at 338 GHz reveal a peak equivalent isotropically radiated power (EIRP) of +17.1 dBm and a phase noise of -93 dBc/Hz at the 1 MHz offset frequency. This chip presents the first fully integrated terahertz phased array on silicon. Furthermore, the output power is higher than any lens-less silicon-based source above 200 GHz and the phase noise is lower than all silicon radiating sources above 100 GHz.
TL;DR: In this article, a dual-loop optoelectronic oscillator based on stimulated Brillouin scattering (SBS) was used to achieve a frequency range from dc to 60 GHz.
Abstract: A dual-loop optoelectronic oscillator (OEO) based on stimulated Brillouin scattering (SBS) is experimentally demonstrated. Two lasers are utilized to realize the tunability of the OEO. One acts as the signal laser, the other is employed as the pump laser. By directly tuning the wavelength of the pump laser, a widely tunable range from dc to 60 GHz for the RF signal generation can be obtained. To the best of our knowledge, this is the widest fundamental frequency tunable range which has ever been achieved by an OEO. With dual-loop fiber lengths of 2 and 4 km, the single sideband (SSB) phase noise is measured to be −100 dBc/Hz at 10 kHz offset when the oscillation frequency is chosen as 5, 10, or 20 GHz. The side-mode suppression ratio (SMSR) is 35 dB when the oscillation frequency is 10 GHz. The stability of both frequency and power of the proposed OEO is improved with the dual-loop configuration when compared with the single-loop one. The Allan variances of the frequency fluctuation at 1-s average are $1.2\times10^{-7}$ and $4.9\times10^{-11}$ for the single-loop and dual-loop configurations, respectively. Furthermore, a phase noise model based on control theory to evaluate the SSB phase noise performance of the dual-loop OEO based on SBS is detailed for the first time. The experimental phase noise results agree well with the proposed phase noise model at an offset frequency range from 100 Hz to 100 MHz. Among different phase noise tests, the amplified spontaneous emission (ASE) noise induced by SBS is shown theoretically and experimentally to be the dominant source for the phase noise beyond 100-kHz frequency offset in the proposed OEO.
TL;DR: This work has successfully achieved a 2048 QAM transmission with a potential spectral efficiency of 15.3 bit/s/Hz in a single carrier coherent transmission over 150 km.
Abstract: We describe a 2048 QAM single-carrier coherent optical transmission over 150 km in detail. The OSNR at the transmitter was increased by 5 dB and the phase noise at the receiver was reduced from 0.35 to 0.17 degrees compared with a previous 1024 QAM transmission. Furthermore, we employed an A/D converter with a higher ENOB (7 bit) to guarantee the SNR of the digital QAM data, and introduced a polarization-demultiplexing algorithm to fast track the polarization state transition. As a result, a 66 Gbit/s polarization-multiplexed 2048 QAM signal was successfully transmitted within an optical bandwidth of 3.6 GHz including a pilot tone, and a potential SE of 15.3 bit/s/Hz under a 20% FEC overhead was achieved.
TL;DR: In this article, a photonic multichannel terahertz (THz) wireless system with up to four optical subcarriers and total capacity as high as 100 Gb/s by employing an externally injected gain-switched laser comb source was demonstrated.
Abstract: We propose and experimentally demonstrate a photonic multichannel terahertz (THz) wireless system with up to four optical subcarriers and total capacity as high as 100 Gb/s by employing an externally injected gain-switched laser comb source. Highly coherent multiple optical carriers with different spacing are produced using the gain switching technique. Single- and multichannel Terahertz (THz) wireless signals are generated using heterodyne mixing of modulated single or multiple carriers with one unmodulated optical tone spaced by about 200 GHz. The frequency stability and the phase noise of the gain switched comb laser are evaluated against free-running lasers. Wireless transmission is demonstrated for single and three optical subcarriers modulated with 8 or 10 GBd quadrature phase-shift keying (QPSK) (48 or 60 Gb/s, respectively) or for four optical subcarriers modulated with 12.5 GBd QPSK (100 Gb/s). The system performance was evaluated for single- and multicarrier wireless THz transmissions at around 200 GHz, with and without 40 km fiber transmission. The system is also modeled to study the effect of the cross talk between neighboring subcarriers for correlated and decorrelated data. This system reduces digital signal processing requirements due to the high-frequency stability of the gain-switched comb source, increases the overall transmission rate, and relaxes the optoelectronic bandwidth requirements.
TL;DR: The main idea is to enforce a clipped voltage waveform around the LC tank by increasing the second-harmonic of fundamental oscillation voltage through an additional impedance peak, thus giving rise to a class-F 2 operation, which minimizes its phase noise.
Abstract: In this paper, we propose a new class of operation of an RF oscillator that minimizes its phase noise. The main idea is to enforce a clipped voltage waveform around the LC tank by increasing the second-harmonic of fundamental oscillation voltage through an additional impedance peak, thus giving rise to a class-F 2 operation. As a result, the noise contribution of the tail current transistor on the total phase noise can be significantly decreased without sacrificing the oscillator's voltage and current efficiencies. Furthermore, its special impulse sensitivity function (ISF) reduces the phase sensitivity to thermal circuit noise. The prototype of the class-F 2 oscillator is implemented in standard TSMC 65 nm CMOS occupying 0.2 mm 2 . It draws 32–38 mA from 1.3 V supply. Its tuning range is 19% covering 7.2–8.8 GHz. It exhibits phase noise of -\hbox {139 dBc/Hz} at 3 MHz offset from 8.7 GHz carrier, translated to an average figure-of-merit of 191 dBc/Hz with less than 2 dB variation across the tuning range. The long term reliability is also investigated with estimated >10 year lifetime.
Book•
01 Jan 2015
TL;DR: Phase-Locking in High-Performance Systems: From Devices to Architectures is a superb reference for anyone working on, or seeking to better understand, this rapidly-developing and increasingly central technology.
Abstract: From the Publisher:
Comprehensive coverage of recent developments in phase-locked loop technology
The rapid growth of high-speed semiconductor and communication technologies has helped make phase-locked loops (PLLs) an essential part of memories, microprocessors, radio-frequency (RF) transceivers, broadband data communication systems, and other burgeoning fields. Complementing his 1996 Monolithic Phase-Locked Loops and Clock Recovery Circuits (Wiley-IEEE Press), Behzad Razavi now has collected the most important recent writing on PLL into a comprehensive, self-contained look at PLL devices, circuits, and architectures.
Phase-Locking in High-Performance Systems: From Devices to Architectures five original tutorials and eighty-three key papers provide an eminently readable foundation in phase-locked systems. Analog and digital circuit designers will glean a wide range of practical information from the books . . .
Tutorials dealing with devices, delay-locked loops (DLLs), fractional-N synthesizers, bang-bang PLLs, and simulation of phase noise and jitter
In-depth discussions of passive devices such as inductors, transformers, and varactors
Papers on the analysis of phase noise and jitter in various types of oscillators
Concentrated examinations of building blocks, including the design of oscillators, frequency dividers, and phase/frequency detectors
Articles addressing the problem of clock generation by phase-locking for timing and digital applications, RF synthesis, and the application of phase-locking to clock and data recovery circuits
In tandem with its companion volume, Phase-Locking in High-Performance Systems: From Devices to Architectures is a superb reference for anyone working on, or seeking to better understand, this rapidly-developing and increasingly central technology.
TL;DR: A novel time-gated digital optical frequency domain reflectometry (TGD-OFDR) technique with high spatial resolution over long measurement range is proposed and experimentally demonstrated and provides a simple-structure and high-performance solution for the applications where both high spatialresolution and long distance range are required.
Abstract: A novel time-gated digital optical frequency domain reflectometry (TGD-OFDR) technique with high spatial resolution over long measurement range is proposed and experimentally demonstrated. To solve the contradictory between the tuning rate of lightwave frequency, which determines the spatial resolution, and the measurable distance range in traditional OFDR, our proposed scheme sweeps the frequency of probe beam only within a time window, while the local reference remains a frequency-stable continuous lightwave. The frequency-to-distance mapping is digitally realized with equivalent references in data domain. In demonstrational experiments, a 1.6-m spatial resolution is obtained over an entire 110-km long fiber link, proving that the phase noises of the laser source as well as environmental perturbations are well suppressed. Meanwhile, the dynamic range was 26 dB with an average of only 373 measurements. The proposed reflectometry provides a simple-structure and high-performance solution for the applications where both high spatial resolution and long distance range are required.
TL;DR: A cascaded optical link of 1100 km for ultra-stable frequency distribution over an Internet fiber network and was extended to 1480-km with the same performance, a significant step towards a sustainable wide area ultra- stable optical frequency distribution and comparison network at a very high level of performance.
Abstract: We report a cascaded optical link of 1100 km for ultra-stable frequency distribution over an Internet fiber network. The link is composed of four spans for which the propagation noise is actively compensated. The robustness and the performance of the link are ensured by five fully automated optoelectronic stations, two of them at the link ends, and three deployed on the field and connecting the spans. This device coherently regenerates the optical signal with the heterodyne optical phase locking of a low-noise laser diode. Optical detection of the beat-note signals for the laser lock and the link noise compensation are obtained with stable and low-noise fibered optical interferometer. We show 3.5 days of continuous operation of the noise-compensated 4-span cascaded link leading to fractional frequency instability of 4x10(-16) at 1-s measurement time and 1x10(-19) at 2000 s. This cascaded link was extended to 1480-km with the same performance. This work is a significant step towards a sustainable wide area ultra-stable optical frequency distribution and comparison network at a very high level of performance.
TL;DR: In this article, a fully monolithic complimentary metal-oxide- semiconductor-microelectormechanical systems (CMOS-MEMS) oscillator comprised of an ovenized double-ended tuning fork resonator was demonstrated to enable ultra-low heater power operation of only 0.47 mW over entire temperature span ( −40 °C to 85 °C) and a low noise sustaining circuit to achieve low phase noise.
Abstract: A fully monolithic complimentary metal–oxide– semiconductor-microelectormechanical systems (CMOS-MEMS) oscillator comprised of an ovenized double-ended tuning fork resonator to enable ultra-low heater power operation of only 0.47 mW over entire temperature span (–40 °C to 85 °C) and a low noise sustaining circuit to achieve low phase noise has been demonstrated in a Taiwan Semiconductor Manufacturing Company (TSMC) 0.35- $\mu $ m CMOS process. The combination of low thermal conductivity material and high thermal isolation design is the key to attaining ultra-low-power heater operation in a sub-mW level. Passive temperature compensation scheme is also conducted in the proposed CMOS-MEMS resonator by an oxide-metal composite structure, showing a low temperature coefficient of frequency (TC $_{f}$ ) of only +5.1 ppm/°C, which is suited for the use in ovenized oscillator systems. By implementing a constant-resistance temperature control scheme, the frequency drift of the resonator smaller than 120 ppm from −40 °C to 85 °C is demonstrated in this paper, indicating an equivalent TC $_{f}$ smaller than 1 ppm/°C, a record-low value against its CMOS-MEMS counterparts. The CMOS-MEMS oscillator operating at 1.2 MHz demonstrates a phase noise of −112 dBc/Hz at 1-kHz offset and −120 dBc/Hz at 1-MHz offset while drawing less than 1.3 mW. The entire power consumption of the ovenized oscillator system is confirmed to be less than 1.8 mW (oscillator + micro-oven), verifying the great potential of low power oven-controlled MEMS oscillators realized in CMOS-MEMS technology. [2014-0068]
TL;DR: An in depth analysis of phase noise, based on direct derivation of the Impulse Sensitivity Function (ISF), provides design insights on the optimization of the tail resonators.
Abstract: A complementary p-n class-B oscillator with two magnetically coupled second harmonic tail resonators is presented and compared to an N-only reference one An in depth analysis of phase noise, based on direct derivation of the Impulse Sensitivity Function (ISF), provides design insights on the optimization of the tail resonators In principle the complementary p-n oscillator has the same optimum Figure of Merit (FoM) of the N-only at half the voltage swing At a supply voltage of 15 V, the maximum allowed oscillation amplitude of the N-only is constrained, by reliability considerations, to be smaller than the value that corresponds to the optimum FoM even when 18 V thick oxide transistors are used For an oscillation amplitude that ensures reliable operation and the same tank, the p-n oscillator achieves a FoM 2 to 3 dB better than the N, only depending on the safety margin taken in the design After frequency division by 2, the p-n oscillator has a measured phase noise that ranges from $-$ 1508 to $-$ 1515 dBc/Hz at 10 MHz offset from the carrier when the frequency of oscillation is varied from 735 to 84 GHz With a power consumption of 63 mW, a peak FoM of 1956 dBc/Hz is achieved
TL;DR: In this paper, the authors present a metrological tool based on randomized benchmarking capable of greatly increasing the precision of Ramsey and spin-echo sequences by the repeated but incoherent addition of phase noise.
Abstract: A precise measurement of dephasing over a range of time scales is critical for improving quantum gates beyond the error correction threshold. We present a metrological tool based on randomized benchmarking capable of greatly increasing the precision of Ramsey and spin-echo sequences by the repeated but incoherent addition of phase noise. We find our superconducting-quantum-interference-device-based qubit is not limited by 1/f flux noise at short time scales but instead observe a telegraph noise mechanism that is not amenable to study with standard measurement techniques.
TL;DR: The receiver front-end meets BLE noise figure, image rejection, phase noise and linearity requirements, and the presented prototype occupies an active area of 0.25 mm 2 while consuming only 0.6 mW.
Abstract: In this paper, a receiver front-end tailored to Bluetooth Low Energy applications is presented. In the proposed solution, the LNA, mixers, VCO, quadrature scheme and the first stage of the analog base-band share the same bias current under a 0.8 V voltage supply leading to a sub-mW power consumption. A channel selection filter, implemented through a current re-use gm-C topology, completes the design. The presented prototype, realized in 130 nm CMOS technology, occupies an active area of 0.25 mm $^{2}$ while consuming only 0.6 mW. With a NF of 15.8 dB, an IIP3 of $-$ 17 dBm at the maximum gain and an image rejection above 30 dB the receiver front-end meets BLE noise figure, image rejection, phase noise and linearity requirements.
Posted Content•
TL;DR: The impact of phase noise on the signal-to-interference-plus-noise ratio (SINR) can be quantified as an effective reduction in the quality of the channel state information (CSI) available at the BS when compared with a system without phase noise.
Abstract: We study the impact of phase noise on the downlink performance of a multi-user multiple-input multiple-output system, where the base station (BS) employs a large number of transmit antennas $M$. We consider a setup where the BS employs $M_{\mathrm{osc}}$ free-running oscillators, and $M/M_{\mathrm{osc}}$ antennas are connected to each oscillator. For this configuration, we analyze the impact of phase noise on the performance of the regularized zero-forcing (RZF), when $M$ and the number of users $K$ are asymptotically large, while the ratio $M/K=\beta$ is fixed. We analytically show that the impact of phase noise on the signal-to-interference-plus-noise ratio (SINR) can be quantified as an effective reduction in the quality of the channel state information available at the BS when compared to a system without phase noise. As a consequence, we observe that as $M_{\mathrm{osc}}$ increases, the SINR performance of all considered precoders degrades. On the other hand, the variance of the random phase variations caused by the BS oscillators reduces with increasing $M_{\mathrm{osc}}$. Through Monte-Carlo simulations, we verify our analytical results, and compare the performance of the precoders for different phase noise and channel noise variances. For all considered precoders, we show that when $\beta$ is small, the performance of the setup where all BS antennas are connected to a single oscillator is superior to that of the setup where each BS antenna has its own oscillator. However, the opposite is true when $\beta$ is large and the signal-to-noise ratio at the users is low.
TL;DR: In this article, a low-phase-noise on-chip Kerr frequency comb with mode spacing compatible with high-speed silicon optoelectronics is presented. But, the frequency spacing of the Kerr comb was not considered.
Abstract: Laser frequency combs are coherent light sources that simultaneously provide pristine frequency spacings for precision metrology and the fundamental basis for ultrafast and attosecond sciences. Recently, nonlinear parametric conversion in high-Q microresonators has been suggested as an alternative platform for optical frequency combs, though almost all in 100 GHz frequencies or more. Here we report a low-phase-noise on-chip Kerr frequency comb with mode spacing compatible with high-speed silicon optoelectronics. The waveguide cross-section of the silicon nitride spiral resonator is designed to possess small and flattened group velocity dispersion, so that the Kerr frequency comb contains a record-high number of 3,600 phase-locked comb lines. We study the single-sideband phase noise as well as the long-term frequency stability and report the lowest phase noise floor achieved to date with −130 dBc/Hz at 1 MHz offset for the 18 GHz Kerr comb oscillator, along with feedback stabilization to achieve frequency Allan deviations of 7 × 10−11 in 1 s. The reported system is a promising compact platform for achieving self-referenced Kerr frequency combs and also for high-capacity coherent communication architectures.
TL;DR: The demonstration that the phase noise of these nanoscale nonlinear oscillators can be tuned and eventually lessened, represents a key achievement for targeted radio frequency applications using spin torque devices.
Abstract: We investigate experimentally the synchronization of vortex based spin transfer nano-oscillators to an external rf current whose frequency is at multiple integers, as well as at an integer fraction, of the oscillator frequency. Through a theoretical study of the locking mechanism, we highlight the crucial role of both the symmetries of the spin torques and the nonlinear properties of the oscillator in understanding the phase locking mechanism. In the locking regime, we report a phase noise reduction down to $\ensuremath{-}90\text{ }\text{ }\mathrm{dBc}/\mathrm{Hz}$ at 1 kHz offset frequency. Our demonstration that the phase noise of these nanoscale nonlinear oscillators can be tuned and eventually lessened, represents a key achievement for targeted radio frequency applications using spin torque devices.
TL;DR: In this paper, a performance estimation for broadband wireless links dedicated to multiple tens of Gbit data rate based on known approaches is presented and verified the validity of the estimation by comparison with measurements performed on an E-band wireless frontend for quadrature phase shift keying modulated signals and symbol rates of 2 and 5 GBd.
Abstract: With the growing interest in high-speed millimeter-wave (mmw) and sub-mmw communication links, detailed studies on the performance limits introduced by nonideal frontend characteristics, eg, in-phase/quadrature amplitude and phase imbalance, as well as local oscillator phase noise, become indispensable Only with a detailed insight into the system’s behavior, a proper dimensioning and optimization of such wireless links is possible In this paper we present a performance estimation for broadband wireless links dedicated to multiple tens of Gbit data rate based on known approaches and verify the validity of the estimation by comparison with measurements performed on an E-band wireless frontend For quadrature phase-shift keying modulated signals and symbol rates of 2 and 5 GBd, the relative error between estimation and measurement is between 11 and 21% Furthermore, the estimation approach is used to investigate the performance limiting imperfection of wireless systems operating in the sub-mmw frequency range Besides the channel noise, the phase noise of the carrier signal is determined as the main limiting factor, especially for systems utilizing extremely broadband modulation bandwidths
TL;DR: A phase unwrapping algorithm for interferometric fringes based on the unscented Kalman filter (UKF) technique is proposed andSimulations indicate that the proposed algorithm has better accuracy than some widely employed phase unwRApping approaches in the same noise condition.
Abstract: A phase unwrapping algorithm for interferometric fringes based on the unscented Kalman filter (UKF) technique is proposed. The algorithm can bring about accurate phase unwrapping and good noise suppression simultaneously by incorporating the true phase and its derivative in the state vector estimation through the UKF process. Simulations indicate that the proposed algorithm has better accuracy than some widely employed phase unwrapping approaches in the same noise condition. Also, the time consumption of the algorithm is reasonably acceptable. Applications of the algorithm in our different optical interferometer systems are provided to demonstrate its practicability with good performance. We hope this algorithm can be a practical approach that can help to reduce the systematic errors significantly induced by phase unwrapping process for interferometric measurements such as wavefront distortion testing, surface figure testing of optics, etc.
TL;DR: In this article, the authors investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs) and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length.
Abstract: In this paper, we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description, we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations, and in particular, we show the possibility of efficiently mitigating both self-phase modulation (SPM)-induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation, the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of $1\times 10^{-3}$ .
TL;DR: This paper presents the first published multiplying delay-locked loop achieving fine fractional-N frequency resolution, and introduces an automatic cancellation of the phase detector offset, by insertion of a digital-to-time converter in the reference path.
Abstract: Although multiplying delay-locked loops allow clock frequency multiplication with very low phase noise and jitter, their application has been so far limited to integer-N multiplication, and the achieved reference-spur performance has been typically limited by time offsets. This paper presents the first published multiplying delay-locked loop achieving fine fractional-N frequency resolution, and introduces an automatic cancellation of the phase detector offset. Both capabilities are enabled by insertion of a digital-to-time converter in the reference path. The proposed synthesizer, implemented in a standard 65 nm CMOS process, occupies a core area of 0.09 mm $^{2}$ , and generates a frequency ranging between 1.6 and 1.9 GHz with a 190 Hz resolution from a 50 MHz quartz-based reference oscillator. In fractional-N mode, the integrated RMS jitter, including random and deterministic components, is below 1.4 ps at 3 mW power consumption, leading to a jitter-power figure of merit of $-$ 232 dB. In integer-N mode, the circuit achieves RMS jitter of 0.47 ps at 2.4 mW power and figure of merit of $-$ 243 dB. Thanks to the adoption of the automatic offset cancellation, the reference-spur level is reduced from $-$ 32 to $-$ 55 dBc.
TL;DR: In this article, the white noise to phase noise conversion of one and two-port CMOS harmonic oscillators with transformer-based resonators is addressed, and a rigorous approach is employed to approximate the transformer network with a second-order RLC model near the resonances.
Abstract: The white noise to phase noise conversion of one- and two-port CMOS differential-pair harmonic oscillators with transformer-based resonators is addressed in this paper. First, the operation of double-tuned transformer resonators is reviewed and design guidelines are proposed to maximize the quality factor. A rigorous approach is then employed to approximate the transformer network with a second order RLC model near the resonances, greatly simplifying the problem of handling the complex equations of a higher order resonator. The results are applied to phase noise calculations, leading to simple, yet accurate, closed-form $1/f^{2}$ phase noise expressions in excellent agreement with the simulation results. It is formally proved, in a general case, that high-order resonators do not provide any fundamental advantage in comparison with simple LC-tanks. The two-port transformer based oscillator may be exploited to limit the phase noise contribution of the core transistors through optimization of the bias point and by leveraging the transformer voltage gain.