1,533 research outputs found
RF CMOS Oscillators for Modern Wireless Applications
While mobile phones enjoy the largest production volume ever of any consumer electronics products, the demands they place on radio-frequency (RF) transceivers are particularly aggressive, especially on integration with digital processors, low area, low power consumption, while being robust against process-voltage-temperature variations. Since mobile terminals inherently operate on batteries, their power budget is severely constrained. To keep up with the ever increasing data-rate, an ever-decreasing power per bit is required to maintain the battery lifetime. The RF oscillator is the second most power-hungry block of a wireless radio (after power amplifiers). Consequently, any power reduction in an RF oscillator will greatly benefit the overall power efficiency of the cellular transceiver. Moreover, the RF oscillators' purity limits the transceiver performance. The oscillator's phase noise results in power leakage into adjacent channels in a transmit mode and reciprocal mixing in a receive mode. On the other hand, the multi-standard and multi-band transceivers that are now trending demand wide tuning range oscillators. However, broadening the oscillator’s tuning range is usually at the expense of die area (cost) or phase noise. The main goal of this book is to bring forth the exciting and innovative RF oscillator structures that demonstrate better phase noise performance, lower cost, and higher power efficiency than currently achievable. Technical topics discussed in RF CMOS Oscillators for Modern Wireless Applications include: Design and analysis of low phase-noise class-F oscillators Analyze a technique to reduce 1/f noise up-conversion in the oscillators Design and analysis of low power/low voltage oscillators Wide tuning range oscillators Reliability study of RF oscillators in nanoscale CMO
Electro-optomechanical equivalent circuits for quantum transduction
Using the techniques of optomechanics, a high- mechanical oscillator may
serve as a link between electromagnetic modes of vastly different frequencies.
This approach has successfully been exploited for the frequency conversion of
classical signals and has the potential of performing quantum state transfer
between superconducting circuitry and a traveling optical signal. Such
transducers are often operated in a linear regime, where the hybrid system can
be described using linear response theory based on the Heisenberg-Langevin
equations. While mathematically straightforward to solve, this approach yields
little intuition about the dynamics of the hybrid system to aid the
optimization of the transducer. As an analysis and design tool for such
electro-optomechanical transducers, we introduce an equivalent circuit
formalism, where the entire transducer is represented by an electrical circuit.
Thereby we integrate the transduction functionality of optomechanical systems
into the toolbox of electrical engineering allowing the use of its
well-established design techniques. This unifying impedance description can be
applied both for static (DC) and harmonically varying (AC) drive fields,
accommodates arbitrary linear circuits, and is not restricted to the
resolved-sideband regime. Furthermore, by establishing the quantized
input-output formalism for the equivalent circuit, we obtain the scattering
matrix for linear transducers using circuit analysis, and thereby have a
complete quantum mechanical characterization of the transducer. Hence, this
mapping of the entire transducer to the language of electrical engineering both
sheds light on how the transducer performs and can at the same time be used to
optimize its performance by aiding the design of a suitable electrical circuit.Comment: 30 pages, 9 figure
Two-photon spectra of quantum emitters
We apply our recently developed theory of frequency-filtered and
time-resolved N-photon correlations to study the two-photon spectra of a
variety of systems of increasing complexity: single mode emitters with two
limiting statistics (one harmonic oscillator or a two-level system) and the
various combinations that arise from their coupling. We consider both the
linear and nonlinear regimes under incoherent excitation. We find that even the
simplest systems display a rich dynamics of emission, not accessible by simple
single photon spectroscopy. In the strong coupling regime, novel two-photon
emission processes involving virtual states are revealed. Furthermore, two
general results are unraveled by two-photon correlations with narrow linewidth
detectors: i) filtering induced bunching and ii) breakdown of the
semi-classical theory. We show how to overcome this shortcoming in a
fully-quantized picture.Comment: 27 pages, 8 figure
Entrainment and stimulated emission of auto-oscillators in an acoustic cavity
We report theory, measurements and numerical simulations on nonlinear
piezoelectric ultrasonic devices with stable limit cycles. The devices are
shown to exhibit behavior familiar from the theory of coupled auto-oscillators.
Frequency of auto-oscillation is affected by the presence of an acoustic cavity
as these spontaneously emitting devices adjust their frequency to the spectrum
of the acoustic cavity. Also, the auto-oscillation is shown to be entrained by
an applied field; the oscillator synchronizes to an incident wave at a
frequency close to the natural frequency of the limit cycle. It is further
shown that synchronization occurs here with a phase that can, depending on
details, correspond to stimulated emission: the power emission from the
oscillator is augmented by the incident field. These behaviors are essential to
eventual design of an ultrasonic system that would consist of a number of such
devices entrained to their mutual field, a system that would be an analog to a
laser. A prototype laser is constructed
RF CMOS Oscillators for Modern Wireless Applications
While mobile phones enjoy the largest production volume ever of any consumer electronics products, the demands they place on radio-frequency (RF) transceivers are particularly aggressive, especially on integration with digital processors, low area, low power consumption, while being robust against process-voltage-temperature variations. Since mobile terminals inherently operate on batteries, their power budget is severely constrained. To keep up with the ever increasing data-rate, an ever-decreasing power per bit is required to maintain the battery lifetime. The RF oscillator is the second most power-hungry block of a wireless radio (after power amplifiers). Consequently, any power reduction in an RF oscillator will greatly benefit the overall power efficiency of the cellular transceiver. Moreover, the RF oscillators' purity limits the transceiver performance. The oscillator's phase noise results in power leakage into adjacent channels in a transmit mode and reciprocal mixing in a receive mode. On the other hand, the multi-standard and multi-band transceivers that are now trending demand wide tuning range oscillators. However, broadening the oscillator’s tuning range is usually at the expense of die area (cost) or phase noise. The main goal of this book is to bring forth the exciting and innovative RF oscillator structures that demonstrate better phase noise performance, lower cost, and higher power efficiency than currently achievable. Technical topics discussed in RF CMOS Oscillators for Modern Wireless Applications include: Design and analysis of low phase-noise class-F oscillators Analyze a technique to reduce 1/f noise up-conversion in the oscillators Design and analysis of low power/low voltage oscillators Wide tuning range oscillators Reliability study of RF oscillators in nanoscale CMO
A study of phase noise in colpitts and LC-tank CMOS oscillators
This paper presents a study of phase noise in CMOS Colpitts and LC-tank oscillators. Closed-form symbolic formulas for the 1/f/sup 2/ phase-noise region are derived for both the Colpitts oscillator (either single-ended or differential) and the LC-tank oscillator, yielding highly accurate results under very general assumptions. A comparison between the differential Colpitts and the LC-tank oscillator is also carried out, which shows that the latter is capable of a 2-dB lower phase-noise figure-of-merit (FoM) when simplified oscillator designs and ideal MOS models are adopted. Several prototypes of both Colpitts and LC-tank oscillators have been implemented in a 0.35-/spl mu/m CMOS process. The best performance of the LC-tank oscillators shows a phase noise of -142dBc/Hz at 3-MHz offset frequency from a 2.9-GHz carrier with a 16-mW power consumption, resulting in an excellent FoM of /spl sim/189 dBc/Hz. For the same oscillation frequency, the FoM displayed by the differential Colpitts oscillators is /spl sim/5 dB lower
Waveform engineering in integrated harmonic oscillators: analysis and examples
openThe thesis analyzes the effect of the presence of a 2nd harmonic resonance in the differential LC oscillator’s tank, going inside the different effect that it causes on waveform shapes and phase noise improvement, with different mechanisms. The above analysis is carried out considering different known topologies of harmonic oscillators understanding in which topologies the tecnicque gives advantages in terms of final phase noise of the oscillator
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