Phase Noise Level Research Articles

アンダーサンプリングを用いたフルディジタル位相雑音計測におけるノイズフロアの推定とその特性

This paper describes phase noise floor level of digital phase noise measurement. It has estimated the noise floor level of phase noise from ENOB of the analog to digital converter and sampling frequency. We have discussed phase noise measurement using normal sampling based on sampling theorem and under sampling which samples longer sampling period than the signal under the test. We compared the phase noise spectral density of noise floor between normal sampling and under sampling. As a result, measurement results are in good agreement in both methods.

Millimeter-Wave Transmission for Small-Cell Backhaul in Dense Urban Environment: a Solution Based on MIMO-OFDM and Space-Time Shift Keying (STSK)

Next generation wireless standards will exploit the wide bandwidth available at the millimeter-wave (mm-Wave) frequencies, in particular the $E$ -band (71–76 and 81–86 GHz). This large available bandwidth may be converted into multi-gigabit capacity, when efficient and computationally affordable transceivers are designed to cope with the constrained power budget, the clustered fading, and the high level of phase noise, which actually characterize mm-wave connections. In this paper, we propose a viable multiple-input multiple-output (MIMO) solution for high bit-rate transmission in the $E$ -band with application to small-cell backhaul based on space-time shift keying (STSK) and orthogonal frequency division multiplexing. STSK provides an efficient tradeoff between diversity and multiplexing without inter-channel interference and without the need for large antenna arrays. These features make STSK theoretically preferable over other throughput-oriented space-time coding techniques, namely, spatial multiplexing and spatial modulation, which were recently considered in the literature for mm-wave MIMO applications. In this paper, we consider the most significant channel impairments related to small-cell backhaul in dense urban environment, namely, the correlated fading with and without the presence the line-of-sight, the phase noise, the rain attenuation, and shadowing. In addition, we consider small-size MIMO systems ( $2 \times 2$ and $4 \times 4$ ), and low-cost base station equipments in the perspective of easily deployable small-cell network components. Comparative results, obtained by intensive simulations targeted at assessing link performance and coverage, have clearly shown the superior performance of STSK against counterpart techniques, although obtained at the cost of a somewhat reduced spectral efficiency.

Bandwidth Compensation Technique for Digital PLL

This brief presents a technique for compensating the bandwidth variation of digital phase-locked loops (PLLs) arising due to process, voltage and temperature (PVT) variation induced changes in loop parameters. For a digital PLL with a bang-bang phase detector, the bandwidth also depends on the phase noise level present at the input of the phase detector. The presented technique also compensates for the bandwidth variations induced by variations in phase noise power. The compensation technique is verified by a MATLAB model and transistor-level transient noise simulations.

On the phase noise performance of microwave and millimeter-wave signals generated with versatile Kerr optical frequency combs.

We investigate the phase noise performance of micro- and millimeter-wave signals generated using a ultra-high Q whispering gallery mode disk-resonator with Kerr nonlinearity. Our study focuses on the stability of the optical spectra and on the performances of the corresponding microwave and millimeter-wave beat notes in terms of power and phase noise. The blue slope of an optical mode of the resonator, allowing for the generation of optical frequency combs, is accurately explored in order to identify various comb patterns. Each of these patterns is characterized in the optical and radio-frequency domains. Phase noise levels below -100 dBc/Hz at 10 kHz offset have been achieved for beat notes in the radio-frequency spectrum at 12 GHz, 18 GHz, 24 GHz, 30 GHz, and 36 GHz with the same resonator.

A Low-Phase-Noise 77-GHz FMCW Radar Transmitter With a 12.8-GHz PLL and a <inline-formula> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula>6 Frequency Multiplier

In this letter, a 77-GHz transmitter (TX) with a 12.8-GHz phase-locked-loop (PLL) and a $\times$ 6 frequency multiplier is presented for a FMCW radar sensor in a 65-nm CMOS process. To realize the low-phase-noise TX, a voltage controlled oscillator (VCO) with an excellent phase noise performance at a lower fundamental frequency (12.8 GHz) is designed and scaled up ( $\times$ 6) for the desired target frequency (77 GHz). The measured FMCW modulation range with an external triangular chirp signal (1-ms sweep time) is 601 MHz. The output power and the total DC power consumption of the TX are 8.9 dBm and 116.7 mW, respectively. Here, a good phase noise level of −91.16 dBc/Hz at a 1-MHz offset frequency from a 76.81-GHz carrier is achieved.

Filtering SAR interferometric phase noise using a split-window model

ABSTRACTFor interferometric synthetic aperture radar (InSAR) processing, the features of interferometric phase obtained in different coherence regions usually differ from each other. This is called region effect and exists in InSAR coherence map. When coherence value is used as a parameter to filter the phase noise, the result will be highly affected by this region effect. In this paper, we propose a new method of filtering InSAR phase noise using a split-window model. The idea of this method is to incorporate several filters into the model. Different filters will be used when dealing with phase noise locates in different coherence regions. The over-filtering or under-filtering caused by the coherence region effect can be eliminated in this method. As an example to demonstrate the superiority of this method, we incorporated an improved Goldstein filter and empirical mode decomposition filter into the current model. They were included to control phase noise level in the low- and high-coherence regions, respectively. The quantitative results obtained using a COnstellation of small Satellites for the Mediterranean basin Observation (COSMO-SkyMed) image pair over Kilauea volcano in Hawaiian demonstrate the advantages of the newly developed split-window model in filtering different types of noise.

Self-Stabilized Optoelectronic Oscillator Using Frequency-Shifted Feedback and a Delay Line

We report a new scheme of photonic microwave oscillator at telecommunication wavelength. It consists of two monolithic distributed feedback (DFB) laser diodes, whose beat-note is stabilized by means of frequency-shifted optical feedback. The feedback beam is modulated by the delayed beat-note itself, and this permits to get a stable optically carried microwave without the need of any external reference. Dual and single sideband modulation schemes were tested by using an intensity modulator and a frequency shifter, respectively. The single sideband scheme results in a better stability and a 10 dB improvement of the phase noise. A phase noise level of −65 dBc/Hz, detection limited, at 100 Hz from a 12 GHz carrier is obtained.

Mode-hopping suppression in long Brillouin fiber laser with non-resonant pumping.

We propose a reliable method for stabilizing narrow linewidth Brillouin fiber lasers with non-resonant pumping. Mode-hopping is suppressed by means of a phase-locked loop that locks the pump-Stokes detuning to a local radio-frequency (RF) oscillator. Stable single-mode operation of a 110-m-long Brillouin fiber laser oscillating at 1.55 μm is demonstrated for several hours. The beat note between two independent Stokes waves presents a phase noise level of -60 dBc/Hz at 100 Hz with a -20 dB/decade slope, and a FWHM linewidth lower than 50 Hz.

Dual‐feedback digital linearisation structure with phase noise mitigation

A digital predistortion (DPD) architecture is proposed to mitigate the phase noise of the local oscillator (LO). In this architecture, a novel dual-feedback structure is designed to simultaneously capture the input and output signals of the power amplifier (PA) to perform the PA modelling and DPD linearisation, and thus relax the requirement on the LO phase noise. Experimental results validate the superior performances of the proposed linearisation architecture over the conventional DPD with LO phase noise. It is verified that the proposed DPD can achieve satisfactory performances even with low-quality LOs of high phase noise levels.

A comparative analysis of measurement noise and multipath for four constellations: GPS, BeiDou, GLONASS and Galileo

With the rapid development of BeiDou system (BDS) and steady progress of Galileo system, the current GNSS (Global Navigation Satellite System) constellations consist of GPS, GLONASS, BeiDou and Galileo. The real signals from the four constellations have been available, which allows us to analyse and compare their measurement noises and multipath effects. In this study, a zero-baseline test is conducted using two ‘Trimble NetR9’ receivers to assess and compare the noises and multipath of measurements on multiple frequencies from the four satellite systems. The zero-baseline double difference approach is utilised to analyse the receiver noises. The code multipath combination and triple-frequency carrier phase combination approaches are exploited to analyse a comprehensive effect of the multipath and noises on the code and carrier phase measurements, respectively. Based on the analysis of the zero-baseline dataset, the results indicate that the code measurement noise levels range from 5 to 25 cm while the carrier phase noise levels vary within 0.9–1.5 mm for different frequencies and constellations. The code multipath and noise (CMN) level for GLONASS is the largest with a root mean square (RMS) value of 39 cm on both G1 and G2 frequencies whereas the Galileo code measurements exhibit a smallest level on the E5 frequency with a RMS value of only 10 cm. The RMS of the carrier phase multipath and noises (PMN) ranges from 1.3 to 2.6 mm for BeiDou and Galileo satellites. By contrast, the triple-frequency carrier phase combinations from the GPS Block IIF satellites demonstrate a much larger RMS value of 5.6 mm owing to an effect of inter-frequency clock biases.

Design and analysis of RF-low power and low-phase noise CMOS ring oscillator for fully integrated RF communication systems technologies

This manuscript presents the design and analysis of five-stage, low power ring oscillator. The ring oscillator has implemented in 0.18 µm CMOS one-poly six-metal-layer process technology and designed for frequency synthesiser module used in RF communication applications. This work uses a single ended topology and the delay cell is designed with both tail-ahead and tail-current concept for frequency improvement. This work projects the effect of transistor size w/l on the important parameters of oscillator viz. frequency and power dissipation. Measurements show that the oscillator covers a frequency range of 0.9-2 GHz. Their analyses demonstrate that the circuit consumes minimum power of 305 µW at 0.9 GHz and maximum 575 µW at 2 GHz oscillating frequency. The designed oscillator occupies an area of 296 * 130 µm² and manifest an improved phase noise level of −111.9 dBc/Hz.

An Adaptively Biased Class-C VCO With a Self-Turn-Off Auxiliary Class-B Pair for Fast and Robust Startup

In this letter, an adaptively biased class-C Voltage Controlled Oscillator (VCO) with a self-turn-off auxiliary class-B pair is presented for fast and robust startup in a 65-nm CMOS process. It consists of a main class-C core and an auxiliary class-B cross-coupled pair. The class-B auxiliary pair is used to solve the inherent startup problem of class-C VCOs. It works only during startup and turns itself off when the VCO reaches a steady state using an adaptive bias scheme. The dc current consumption of the VCO and bias circuit is 5 mA at 1.2 V VDD. Here, a good phase noise level of -132.41 dBc/Hz at a 1 MHz offset frequency from a 2.46-GHz carrier is shown, to yield a Figure-of-Merit (FOM) of 192.45.

Digital Embedded Test Instrument for On-Chip Phase Noise Testing of Analog/RF Integrated Circuits

This paper presents a digital embedded test instrument (ETI) for on-chip phase noise (PN) testing of analog/RF integrated circuits. The technique relies on 1–bit signal acquisition and dedicated processing to compute a digital signature related to the PN level. An appropriate algorithm based on on-the-fly processing of the 1-bit signal is defined in order to implement the BIST module with minimal hardware resources. Its implementation in CMOS 140[Formula: see text]nm technology occupies only 7,885[Formula: see text][Formula: see text]m2, which represents an extremely small silicon area. Hardware measurements are performed on an FPGA prototype that validates the proposed instrument.

Phase Noise Testing of Analog/IF Signals Using Digital ATE: A New Post-Processing Algorithm for Extended Measurement Range

This paper deals with low-cost phase noise testing of sinusoidal analog/IF signals. The idea is to perform over-sampled 1-bit signal acquisition using standard digital ATE and to apply dedicated post-processing in order to retrieve the phase noise level present in the analog/IF signal from the captured binary vector. A first algorithm has already been developed, which shows an excellent agreement with conventional phase noise measurements on a large range of injected noise but diverges from conventional method in case of very low phase noise level. In this paper, we present a new processing algorithm that permits to alleviate this limitation. Both simulations and hardware measurements are realized to validate the technique and results clearly demonstrate the improved performance of the new algorithm.

Synthesis Concepts of Signals With High Spectral Purity for the Use in Impulse Radar Systems

This paper focuses on the synthesis of ultralow-noise signals for the use in a timebase of impulse radar systems. These systems are used in manifold applications and their accuracy is strongly dependent on the spectral purity of the timebase. Current systems use either phase-locked loops (PLLs) or direct digital synthesizers (DDSs). These PLLs comprise an excessive amount of components and recent DDSs still have a low spurious-free dynamic range (SFDR). Therefore, this paper presents two new approaches for the direct synthesis. They are based on frequency dividers with both short division factor sequences and noise-shaping techniques. Ideas for spur avoidance and noise reduction are described to improve the noise behavior in terms of SFDR and phase noise. The presented approaches have been realized in hardware and measurement results are depicted. For the system using frequency dividers with short division factor sequences, the best results are a SFDR better than 117 dB at a signal frequency of 10.7 MHz. The phase noise level is below −140 dBc/Hz at offset frequencies greater than 1 kHz. Regarding the frequency dividers with noise-shaping techniques, no discrete spurious are visible. The phase noise level at offset frequencies greater than 7 kHz is below −150 dBc/Hz. These results are comparable with state-of-the-art PLL concepts and thus confirm the approaches.

Theory of a tunable spin-wave optoelectronic microwave oscillator

A theory that describes the threshold regime of the formation of auto-oscillation spectrum is proposed for a tunable ring optoelectronic microwave oscillator (OEO). The main elements of the OEO are series-connected optical fiber, spin-wave narrow-band microwave film filter, and broadband semiconductor microwave amplifier. It is demonstrated that a relatively low level of the OEO phase noise is provided by both the optical fiber and spin-wave filter.

The Impact of Damping on the Frequency Stability of Nonlinear MEMS Oscillators

Linear models for oscillator noise predict an improvement in frequency stability with increasing quality factor. Although it is well known that this result does not apply to oscillators embedding nonlinear resonators, systematic experimental investigations of the impact of damping on frequency stability of nonlinear microelectromechanical system (MEMS) oscillators has not been previously reported. This paper studies the frequency stability of a nonlinear MEMS oscillator under variable damping conditions. Analytical and experimental investigation of a MEMS square-wave oscillator embedding a double-ended tuning fork resonator driven into the nonlinear regime is introduced. The experimental results indicate that for a preset drive level, the variation of air damping changes the onset of nonlinear behavior in the resonator, which not only impacts the output frequency, but also the phase/frequency noise of a nonlinear MEMS square wave oscillator. The random walk frequency noise and flicker frequency noise levels are strongly correlated with the nonlinear operating point of the resonator, whereas the white phase and white frequency noise levels are impacted both by the output power and by operative nonlinearities.

A 5-GHz LC VCO with digital AAC and AFBS for 2.4 GHz ZigBee transceiver applications

A 5GHz LC VCO (voltage-controlled oscillator) with automatic amplitude control (AAC) and automatic frequency-band selection (AFBS) for 2.4GHz ZigBee transceivers is presented. Instead of continuous feedback loop, an alternative amplitude calibration scheme is proposed in this paper to alleviate the deficiencies inherent in the conventional approach. It helps to keep the VCO at optimum amplitude to avoid saturation of the cross-coupled transistors and therefore stabilizes the phase noise performance over process, voltage and temperature variations. For the ZigBee application with 16 frequency channels, a coarse tuning loop is added in this work to implement the frequency-band selection using the AFBS mechanism. The VCO core and the digital AAC, AFBS modules have been fully integrated in a 2.4GHz ZigBee transceiver which was fabricated in a 0.18μm RF-CMOS technology. The current consumption is 4.7mA at 4.85GHz with 1.8V power supply and a chip area of about 0.285mm2 is occupied. The VCO is capable of operating from 4.67GHz to 5.18GHz and the measured phase-noise level is –120dBc/Hz at 1MHz offset from a 4.85GHz carrier. The tuning sensitivity KVCO of the VCO is about 78MHz/V with 0.9V control voltage.

A Low Close-in Phase Noise 2.4 GHz RF Hybrid Oscillator using a Frequency Multiplier

This paper proposes a 2.4 GHz RF oscillator with a very low close-in phase noise performance. This is composed of a low frequency crystal oscillator and three frequency multipliers such as two doubler (X2) and one tripler (X3). The proposed oscillator is implemented as a hybrid type circuit design using a discrete silicon bipolar transistor. The measurement results of the proposed oscillator structure show -115 dBc/Hz close-in phase noise at 10 kHz offset frequency, while only dissipating 5 mW from a 1-V supply. Its close-in phase noise level is very close to that of a low frequency crystal oscillator with little degradation of noise performance. The proposed structure which is consisted of a low frequency crystal oscillator and a frequency multiplier provides new method to implement a low power low close-in phase noise RF local oscillator.

60 GHz Radio Over Fiber System Based on Gain-Switched Laser

A radio over fiber (RoF) transmission system based on a gain-switched laser as an optical comb source is proposed and demonstrated. 12.5 Gb/s 16 quadrature amplitude modulation (16 QAM) signal generation and transmission over 25 km standard single-mode fiber is experimentally demonstrated using a 60 GHz carrier. The phase noise of the 60 GHz signal resulting from the beating of two partially phase uncorrelated optical tones is theoretically studied and experimentally investigated. Phase noise comparison with different linewidth comb sources is implemented in the proposed RoF system, and the performance of the various systems with different levels of phase noise is presented.