2,463 research outputs found
A New Technique for the Design of Multi-Phase Voltage Controlled Oscillators
© 2017 World Scientific Publishing Company.In this work, a novel circuit structure for second-harmonic multi-phase voltage controlled oscillator (MVCO) is presented. The proposed MVCO is composed of (Formula presented.) ((Formula presented.) being an integer number and (Formula presented.)2) identical inductor–capacitor ((Formula presented.)) tank VCOs. In theory, this MVCO can provide 2(Formula presented.) different phase sinusoidal signals. A six-phase VCO based on the proposed structure is designed in a TSMC 0.18(Formula presented.)um CMOS process. Simulation results show that at the supply voltage of 0.8(Formula presented.)V, the total power consumption of the six-phase VCO circuit is about 1(Formula presented.)mW, the oscillation frequency is tunable from 2.3(Formula presented.)GHz to 2.5(Formula presented.)GHz when the control voltage varies from 0(Formula presented.)V to 0.8(Formula presented.)V, and the phase noise is lower than (Formula presented.)128(Formula presented.)dBc/Hz at 1(Formula presented.)MHz offset frequency. The proposed MVCO has lower phase noise, lower power consumption and more outputs than other related works in the literature.Peer reviewedFinal Accepted Versio
Broadband squeezing of quantum noise in a Michelson interferometer with Twin-Signal-Recycling
Twin-Signal-Recycling (TSR) builds on the resonance doublet of two optically
coupled cavities and efficiently enhances the sensitivity of an interferometer
at a dedicated signal frequency. We report on the first experimental
realization of a Twin-Signal-Recycling Michelson interferometer and also its
broadband enhancement by squeezed light injection. The complete setup was
stably locked and a broadband quantum noise reduction of the interferometers
shot noise by a factor of up to 4\,dB was demonstrated. The system was
characterized by measuring its quantum noise spectra for several tunings of the
TSR cavities. We found good agreement between the experimental results and
numerical simulations
An Integrated Subharmonic Coupled-Oscillator Scheme for a 60-GHz Phased-Array Transmitter
This paper describes the design of an integrated coupled-oscillator array in SiGe for millimeter-wave applications. The design focuses on a scalable radio architecture where multiple dies are tiled to form larger arrays. A 2 × 2 oscillator array for a 60-GHz transmitter is fabricated with integrated power amplifiers and on-chip antennas. To lock between multiple dies, an injection-locking scheme appropriate for wire-bond interconnects is described. The 2 × 2 array demonstrates a 200–MHz locking range and 1 × 4 array formed by two adjacent chips has a 60-MHz locking range. The phase noise of the coupled oscillators is below 100 dBc/Hz at a 1-MHz offset when locked to an external reference. To the best of the authors’ knowledge, this is the highest frequency demonstration of coupled oscillators fabricated in a conventional silicon integrated-circuit process
Quantum Enhancement of the Zero-Area Sagnac Interferometer Topology for Gravitational Wave Detection
Only a few years ago, it was realized that the zero-area Sagnac
interferometer topology is able to perform quantum nondemolition measurements
of position changes of a mechanical oscillator. Here, we experimentally show
that such an interferometer can also be efficiently enhanced by squeezed light.
We achieved a nonclassical sensitivity improvement of up to 8.2 dB, limited by
optical loss inside our interferometer. Measurements performed directly on our
squeezed-light laser output revealed squeezing of 12.7 dB. We show that the
sensitivity of a squeezed-light enhanced Sagnac interferometer can surpass the
standard quantum limit for a broad spectrum of signal frequencies without the
need for filter cavities as required for Michelson interferometers. The Sagnac
topology is therefore a powerful option for future gravitational-wave
detectors, such as the Einstein Telescope, whose design is currently being
studied.Comment: 4 pages, 4 figure
A 12MHz Switched-Capacitor Relaxation Oscillator with a Nearly Minimal FoM of -161dBc/Hz
In this work the phase noise performance of relaxation oscillators has been analyzed resulting in simple though precise phase noise expressions. These expressions have lead to a new relaxation oscillator topology, which exploits a noise filtering technique implemented with a switched-capacitor circuit to minimize phase noise. Measurements on a 65nm CMOS design show a sawtooth waveform, a frequency tuning range between 1 and 12MHz and a rather constant frequency tuning gain. At 12MHz oscillation frequency it consumes 90ÎĽW while the phase noise is -109dBc/Hz at 100KHz offset frequency. By minimizing and balancing noise contributions of charge and discharge mechanisms, a nearly minimal FoM of -161dBc/Hz has been achieved, which is a 6dB improvement over state-of-the-art
Experimental characterization of frequency dependent squeezed light
We report on the demonstration of broadband squeezed laser beams that show a
frequency dependent orientation of the squeezing ellipse. Carrier frequency as
well as quadrature angle were stably locked to a reference laser beam at
1064nm. This frequency dependent squeezing was characterized in terms of noise
power spectra and contour plots of Wigner functions. The later were measured by
quantum state tomography. Our tomograph allowed a stable lock to a local
oscillator beam for arbitrary quadrature angles with one degree precision.
Frequency dependent orientations of the squeezing ellipse are necessary for
squeezed states of light to provide a broadband sensitivity improvement in
third generation gravitational wave interferometers. We consider the
application of our system to long baseline interferometers such as a future
squeezed light upgraded GEO600 detector.Comment: 8 pages, 8 figure
Michelson interferometer with diffractively-coupled arm resonators in second-order Littrow configuration
Michelson-type laser-interferometric gravitational-wave (GW) observatories
employ very high light powers as well as transmissively- coupled Fabry-Perot
arm resonators in order to realize high measurement sensitivities. Due to the
absorption in the transmissive optics, high powers lead to thermal lensing and
hence to thermal distortions of the laser beam profile, which sets a limit on
the maximal light power employable in GW observatories. Here, we propose and
realize a Michelson-type laser interferometer with arm resonators whose
coupling components are all-reflective second-order Littrow gratings. In
principle such gratings allow high finesse values of the resonators but avoid
bulk transmission of the laser light and thus the corresponding thermal beam
distortion. The gratings used have three diffraction orders, which leads to the
creation of a second signal port. We theoretically analyze the signal response
of the proposed topology and show that it is equivalent to a conventional
Michelson-type interferometer. In our proof-of-principle experiment we
generated phase-modulation signals inside the arm resonators and detected them
simultaneously at the two signal ports. The sum signal was shown to be
equivalent to a single-output-port Michelson interferometer with
transmissively-coupled arm cavities, taking into account optical loss. The
proposed and demonstrated topology is a possible approach for future
all-reflective GW observatory designs
Basics of RF electronics
RF electronics deals with the generation, acquisition and manipulation of
high-frequency signals. In particle accelerators signals of this kind are
abundant, especially in the RF and beam diagnostics systems. In modern machines
the complexity of the electronics assemblies dedicated to RF manipulation, beam
diagnostics, and feedbacks is continuously increasing, following the demands
for improvement of accelerator performance. However, these systems, and in
particular their front-ends and back-ends, still rely on well-established basic
hardware components and techniques, while down-converted and acquired signals
are digitally processed exploiting the rapidly growing computational capability
offered by the available technology. This lecture reviews the operational
principles of the basic building blocks used for the treatment of
high-frequency signals. Devices such as mixers, phase and amplitude detectors,
modulators, filters, switches, directional couplers, oscillators, amplifiers,
attenuators, and others are described in terms of equivalent circuits,
scattering matrices, transfer functions; typical performance of commercially
available models is presented. Owing to the breadth of the subject, this review
is necessarily synthetic and non-exhaustive. Readers interested in the
architecture of complete systems making use of the described components and
devoted to generation and manipulation of the signals driving RF power plants
and cavities may refer to the CAS lectures on Low-Level RF.Comment: 36 pages, contribution to the CAS - CERN Accelerator School:
Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar
Design of a 4.2-5.4 GHz differential LC VCO using 0.35 mu m SiGeBiCMOS technology for IEEE 802.11a applications
In this paper, a 4.2-5.4 GHz, -Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 mu m SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post-layout simulation results, phase noise is -110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and -113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation-mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm(2) on Si substrate, including DC and RF pads
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