Phase Noise

A new model describing laser noise in terms of non-Markovian stochastic phase jumps has been recently introduced. In this letter an exact expression for the correlation function for the electric field is obtained. This expression, valid for all possible values of the parameters of the stochastic process, reduces to the previously reported approximations. A procedure is described for the inverse problem of determining the stochastic parameters from measured data for real lasers.

Selection of dynamic dividers in CMOS PLLs for GHzs applications allows remarkable reduction in power loss without affecting phase noise and power supply sensitivity. Frequency dividers are combination of classic TSPC logic (true-single-phase-clock) and E_TSPC logic (extended TSPC). The designed PLL with % 8/9 prescaler is used for wireless LAN applications and synthetic of frequencies between 5.14 to 5.70 GHz. In this paper a % 8/9 prescaler has designed at 0.25 micrometers process for 2.5_3 GHz band width. This prescaler has been designed with 2.5v power supply with using E_TSPC logic. In this circuit in addition to decrement of power consumption, divider can work in a nearly high speed. Subsequently the dimensions of transistors have been improved and power consumption has been reduced from 3.8mw to 2.9mw. Then, the layout of circuit has been designed with L-Edit software. The simulation results of are identical to that we expect according to earlier Spice simulations.

Noise radars, providing near thumbtack autoambiguity signals, allow for fine resolution of targets in range and Doppler measurements. Both correlation processing as well as spectral interferometry require coherence, so the transmitters and receivers must be driven by highly stable oscillators as phase noise introduced into the system degrades the Doppler resolvability of the radar. We offer a technique to estimate the phase noise process through naturally collected radar data and fit stochastic models to the noise process. Phase noise models can be used in parametric correction techniques, which can have drastically reduced computational complexity when compared with nonparametric versions.

Abstract—Finding the optimal size in VLSI circuits such as
voltage controlled oscillator is one of the challenging tasks for IC
designers. VCO is one of the most widely used blocks in both
digital and analog circuits. In this paper, a new approach has
been presented to find the optimum size of transistors in order to
optimize phase noise and power in ring VCOs. In this work, the
gravitational search algorithm (GSA) is employed to optimize the
size of transistors for the purpose of reaching the best phase noise
and power. Tested differential ring VCOs are simulated in 65nm
Cadence Virtuoso by considering the size of transistors extracted
from GSA in MATLAB environment.

We present coherent phase modulation detection for laser phase noise measurements with delayed self-heterodyne method. The technique is demonstrated for the first time with the distributed feedback laser and external cavity laser. The results are within 15% of self-homodyne measurements using an optical coherent receiver.

Phase noise is a topic of theoretical and practical interest in electronic circuits, as well as in other fields such as optics. Although progress has been made in understanding the phenomenon, there still remain significant gaps, both in its fundamental theory and in numerical techniques for its characterisation. In this paper, we develop a solid foundation for phase noise that is valid for any oscillator, regardless of operating mechanism. We establish novel results about the dynamics of stable nonlinear oscillators in the presence of perturbations, both deterministic and random. We obtain an exact, nonlinear equation for phase error, which we solve without approximations for random perturbations. This leads us to a precise characterisation of timing jitter and spectral dispersion, for computing which we develop efficient numerical methods. We demonstrate our techniques on practical electrical oscillators, and obtain good matches with measurements even at frequencies close to the carrier, where previous techniques break down. we present can be extended [1] for the MNA (Modified Nodal Analysis) formulation (i.e., DAE formulation) given by d=dt qx + f x = 0. 2 After any small disturbance that does not persist, the system asymptotically settles back to the original limit cycle. See [2] for a precise definition of this stability notion.

Pulse wave velocity (PWV ) provides information about the mechanical properties of the vessel: the stiffer the artery is, the higher the PWV will be. PWV measured over a short arterial segment facilitates direct characterization of local wall properties corrected for prevailing pressure without the necessity of measuring pulse pressure locally. Current methods for local PWV assessment have a poor precision, but it can be improved by applying linear regression to a characteristic time-point in distension waveforms as recorded simultaneously by multiple M-line ultrasounds. We investigated the precision of this method in a phantom scaled according to realistic in vivo conditions. Special attention was paid to the identification of the foot of the wave, using the maximum of the second derivative, the intersecting tangent and the 20% threshold method. Before foot detection, the distension waveforms were subjected to preprocessing with various filters. The precision of the maximum of the second derivative had a coefficient of variation (CV ) of 0.45% and 10.45% for an eighth and second order low pass filter, respectively. The intersecting tangent and the threshold method were less sensitive to filtering; the CVs were 0.66% and 0.68% for the high order filter and 2.36% and 1.43% for the low order filter, respectively. We conclude that foot detection by a threshold of 20% or by the tangent method are more suitable to identify the foot of the wave to measure local PWV. Both methods are less sensitive to (phase) noise than the maximum of the second derivative method and exhibit good precision with a CV of less than 1%. (E-mail: [email protected])

A regeneratively mode-locked fiber ring laser (RML-FRL) and an active harmonically mode-locked fiber ring laser (ML-FRL) have been characterized for both amplitude and phase noise by investigating the detected RF spectra of the optical pulse trains. Quantification of noise in the optical pulses reveals that the stability of the RML-FRL in terms of noise performance is superior to its ML-FRL counterpart. The optical pulse noise was measured over a frequency band of 100 Hz to 100 kHz and it was found that the pulse amplitude noise reduced from 0.6% in the ML-FRL to 0.3% in the RML-FRL. The total rms noise in the detected optical pulses from the RML-FRL improved by more than 30% compared to that measured for the ML-FRL, with a phase noise improvement of 15 dB at 100 kHz offset frequency from the carrier. An rms timing jitter of 0.38 ps was estimated in the optical pulse train from the ML-FRL, which reduced to 0.26 ps in the RML-FRL. In addition, complete elimination of the relaxation oscillations noise spikes in the detected RF spectrum of the optical pulses from the RML-FRL has been observed.

This paper investigates optical coherent systems based on polarization multiplexing and high-order modulations such as phase-shift keying (PSK) signals and quadrature amplitude modulations (QAM). It is shown that a simple linear receiver processing is sufficient to perfectly demultiplex the two transmitted streams and to perfectly compensate for group velocity dispersion (GVD) and polarization mode dispersion (PMD). In addition, in the presence of a strong phase noise of the lasers at the transmitter and receiver, a symbol-by-symbol detector with decision feedback is able to considerably improve the receiver robustness with a limited complexity increase. We will also discuss the channel estimation and the receiver adaptivity to time-varying channel conditions as well as the problem of the frequency acquisition and tracking. Finally, a new two-dimensional (polarization/time) differential encoding rule is proposed to overcome a polarization-ambiguity problem. In the numerical results, the receiver performance will be assessed versus the receiver complexity.

The Case I, Case II, and Case III distributions for the phase angle between two vectors perturbed by Gaussian noise are restated in terms of integrals with integrands containing only exponentials. Added to these are a Case IV distribution in which one of the vectors is noise free; and Case V, Case VI, and Case VII distributions for the instantaneous radian frequency that results when the time between the two vectors goes to zero. In addition, existing and new forms for the probability density functions corresponding to each of the distributions are given. The results are applied to digital FM with a limiter/discriminator receiver to easily obtain the bit error probability without coding and the corresponding probability density function needed in a Chernoff bound approach to study the bit error probability with coding.

We propose a novel technique allowing the use of the three-cornered-hat method with two devices under test (DUTs) and a time-tagging system that employs a common reference oscillator. The precision of a time-tagging system is reduced by fluctuations in the timebase, which are canceled when the relative phase between the two DUTs is measured. However, the raw timetags in this system provide a phase comparison between the DUTs and the system timebase, allowing the use of the three-cornered hat with some dual-channel measurement instruments.

This paper presents a fully-integrated voltage controlled oscillator working in the 2.45GHz ISM band. It uses the standard differential design as it gives major advantageshigh suppression of noise on the power supply lines, better start-up for a given power consumption. The oscillator achieves very low phase noise of -123dBc/Hz at 1MHz offset from the carrier. Emitter degeneration technique is used to improve the phase noise over the standard design. The power consumption of the oscillator is 8mA from a 3V power supply. The output voltage amplitude is 800mV. The tuning frequency range is 2.38-2.68GHz and the tuning voltage is from 2V to 3 V.

Oscillators are key components of electronic systems. Undesired perturbations, i.e. noise, in practical electronic systems adversely affect the spectral and timing properties of oscillators resulting in phase noise, which is a key performance limiting factor, being a major contributor to bit-error-rate (BER) of RF communication systems, and creating synchronization problems in clocked and sampled-data systems. In this paper, we first present a theory and numerical methods for nonlinear perturbation and noise analysis of oscillators described by a system of differential-algebraic equations (DAEs), which extends our recent results on perturbation analysis of autonomous ordinary differential equations (ODEs). In developing the above theory, we rely on novel results we establish for linear periodically time-varying (LPTV) systems: Floquet theory for DAEs. We then use this nonlinear perturbation analysis to derive the stochastic characterization, including the resulting oscillator spectrum, of phase noise in oscillators due to colored (e.g., 1= f noise), as opposed to white, noise sources. The case of white noise sources has already been treated by us in a recent publication. The results of the theory developed in this work enabled us to implement a rigorous and effective analysis and design tool in a circuit simulator for low phase noise oscillator design.

The paper deals with carrier recovery based on pilot symbols in single-carrier systems. The system model considered in the paper includes the channel additive white noise and the phase noise that affects the local oscillators used for up/downconversion. Wiener's method is used to determine the optimal filter in estimation of phase noise assuming that a sequence of equally spaced pilot symbols is available. Our analysis allows to capture the cyclostationary performance of the estimate, a phenomenon that is not considered in the previous literature. In the paper, closed-form formulas for the transfer function of the optimal filter and for the mean-square phase error are derived for the case where the phase noise is modelled as random phase walk. For this case, a suboptimal filter is proposed. Numerical results are presented to substantiate the analysis.

In this correspondence, an improvement to the realization of the linear-phase IIR filters is described. It is based on the rearrangement of the numerator polynomials of the IIR filter functions that are used in the real-time realizations recently proposed in literature. The new realization has better total harmonic distortion when sine input is used, and it has smaller phase and group delay errors due to finite section length.

Phase noise (PN) impact in communication systems is considered as great, especially in wireless communication systems using higher m-QAM modulation schemes. The objective of this evaluation study is to investigate the exact impact of Phase noise in relation to AWGN, within a wide range of QAM schemes, since an implementation, of higher QAM usage, is anticipated to be widely used in modern wireless communication industry.

Despite the incessant progress observed in fined and wireless terrestrial communication networks, satellite systems remain an appealing solution for broadcasting, point-to-point, and multicasting telecommunications, because of undemanding customer equipment and wide coverage capability. In this scenario, digital video broadcasting via satellite (DVB-S) is recognized as one of the main market-attractive telecommunication fields. U p to now, expensive discrete GaAs HEMT or FET devices have been used to build up circuitry for satellite applications at Kuband. This article presents the first 12-GHz monolithic receiver for DVB-S applications, implemented in a low-cost silicon bipolar technology. The receiver is based on a superheterodyne architecture, employing a fully integrated LO. To comply with the severe LO phase noise requirement of -101 dBclHz at a 100 kHz offset from the carrier, an innovative VCO topology was used implementing a three-metal-layer integrated transformer. The performance parameters of the integrated receiver fulfill DVB-S standard specifications.

This paper describes a method for enhancing speech corrupted by broadband noise. The method is based on the spectral noise subtraction method. The original method entails subtracting an estimate of the noise power spectrum from the speech power spectrum, setting negative differences to zero, recombining the new power spectrum with the original phase, and then reconstructing the time waveform. While this method reduces the broadband noise, it also usually introduces an annoying "musical noise". We have devised a method that eliminates this "musical noise" while further reducing the background noise. The method consists in subtracting an overestimate of the noise power spectrum, and preventing the resultant spectral components from going below a preset minimum level (spectral floor). The method can automatically adapt to a wide range of signal-to-noise ratios, as long as a reasonable estimate of the noise spectrum can be obtained. Extensive listening tests were performed to determine the quality and intelligibility of speech enhanced by our method. Listeners unanimously preferred the quality of the processed speech. Also, for an input signal-to-noise ratio of 5 dB, there was no loss of intelligibility associated with the enhancement technique.

this paper reports a PFD/CP linearization technique and a new charge pump circuit to enhance the performance of a delta-sigma (∆Σ) fractional-N PLL. The proposed method improves the PLL linearity by forcing the PFD/CP to operate in a linear part of its transfer characteristic; while the CP circuit minimizes the current mismatch between the up and down currents by feedback. These circuit techniques are employed in the design of a 2.4-GHz ∆Σ fractional-N PLL. This chip has been fabricated in the TSMC 0.18-µm CMOS process. The experimental results demonstrate that the proposed techniques considerably improve the fractional-N PLL performance. This fully-integrated PLL dissipate 22 mW under a 1.8-V supply.

A two-channel multibit CA audio digital-to-analogconverter (DAC) with on-chip digital phase-locked loop and sample-rate converter is described. The circuit requires no oversampled synchronous clocks to operate and rejects input sample clock jitter above 16 Hz at 6 dB/octave. A second-order modulator with a multibit quantizer, switched-capacitor (SC) DAC, and single-ended second-order SC filter provides a measured out-ofband noise of -63 dBr with less than 0.1' phase nonlinearity.

This paper presents a three-stage CML (current mode logic) ring VCO fabricated in a 0.12 µm SOI CMOS technology with a minimum stage delay of 5.4 ps at a differential voltage swing of 400 mV. The maximum oscillation frequency measured is 31 GHz. A tuning range as high as 10 % is measured. The phase noise is -95.9 dBc at an offset frequency of 10 MHz. The energy per stage is as low as 26.8 fJ at a power supply voltage of 1.5 V and a delay per stage of 5.95 ps.

This letter analyzes the phase noise effects on an orthogonal frequency division multiplexing (OFDM) signal and its dependence with the sub-carrier spacing. Pilot-based channel estimation, which has been suggested as a means of combating the channel effects, can also correct the phase noise effects under some circumstances, which are investigated.

Absrract-The very broad bandwidth of low-loss optical transmission in a single-mode fiber and the recent improvements in single-frequency tunable lasers have stimulated significant advances in dense wavelength division multiplexed optical networks. This technology, including wavelength-sensitive optical switching and routing elements and passive optical elements, has made it possible to consider the use of wavelength as another dimension, in addition to time and space, in network and switch design. The independence of optical signals at different wavelengths makes this a natural choice for multiple-access networks, for applications which benefit from shared transmission media, and for networks in which very large throughputs are required.

Many imaging systems deal with phase measurements using coherent radiation in order to illuminate objects. The reflected scattered return carries information on physical and geometrical properties of illuminated objects. It can be information on shape, deformation, movement and structure of the object's surface. We propose a novel phase unwrap filtering for noisy holographic data. Based on the window size adaptive local polynomial approximation it allows dramatically reduce level of noise and in the same time preserve phase variation features. Simulation shows that the technique enables an advanced accuracy for phase reconstruction from wrapped noisy observations.

Recent results from a Swedish program for development of 60-GHz monolithic microwave integrated circuits (MMICs) for high-data-rate communication links are presented. Front-end circuits such as mixers, amplifiers, frequency multipliers, IF amplifiers with gain control, and voltage-controlled oscillators (VCOs) have been realized utilizing GaAs PHEMT and MHEMT technologies. A newly developed 7.5-GHz coupled Colpitt VCO shows a minimum phase noise of 95 dBc at 100 kHz offset. A second-harmonic 14-GHz VCO shows a minimum phase noise of less than 90 dBc at 100 kHz. A novel balanced 7-28-GHz MMIC frequency quadrupler is described and compared with a single-ended quadrupler at the same input frequencies. To demonstrate its feasibility and potential application, the quadrupler is combined with the Colpitt VCO and the output characteristics of the resulting 30-GHz MMIC source are measured. A three-stage MHEMT wide-band amplifier covering 43-64 GHz with a gain of 24 dB, a minimum noise figure of 2.5 dB, and a passband ripple of 2 dB is also described. In future 60-GHz systems for mass markets where cost is of utmost importance, Si-based technologies, especially CMOS, are highly interesting. Some recent circuit results based on a 90-nm CMOS technology are also reported.

The error vector magnitude (EVM) is extensively applied as a measure of communication systems' performance. In this paper, the effects of gain, phase imbalance, and phase noise on EVM are examined. The work is focused on single-carrier, linear, and memoryless modulated signals, such as phase-shift keying and quadrature amplitude modulation (QAM). The EVM is calculated under the assumption that the transmitted signal consists of zero-mean uncorrelated inphase and quadrature components that are corrupted by additive white Gaussian noise. The contributions of this paper are as follows. First, an expression for the EVM is derived using a simple model that accounts for linear transmitter and receiver imperfections, inspired by the works of Cavers and Liao, 1993. Second, a union bound on the symbol error rate (SER) is derived. The root mean square EVM is shown to be independent of the constellation shape. The SER, however, is sensitive to the individual transmitted symbols and, therefore, the constellation shape. The resulting equations are used to examine the relation between EVM, sideband suppression, and phase noise.

A low phase noise tuned-input tuned-output (TITO) voltage-controlled oscillator (VCO) using PMOS transistors is presented in this article.The TITO-VCO, implemented using a 0.18 μm RF CMOS process, resulted in a phase noise performance of −118 dBc/Hz at 1 MHz offset from the center frequency of 4.7 GHz. The figure-of-merit of the TITO-VCO was 188 dB. To the author's knowledge, this is the first report on the measured performance of differential TITO-VCO implemented using PMOS transistors. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1852–1855, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25341

Two significant requirements in an FMCW radar system are linearity and low phase noise. Especially in range detection applications the achievable accuracy directly depends on the linearity of the modulated radar signal. In general PLL based systems with digital generated reference signals are used to meet this requirement. In this paper an FPGA controlled DDS based signal generator for highly linear frequency sweeps is introduced. Measurements demonstrate the approached linearity of an FMCW radar in the K-band with 1 GHz bandwidth and a sweep time of 50 μs. In addition signal processing aspects for measurements and evaluation are derived.

He is engaged in research and teaching in digital communications and wireless systems, equalization and channel estimation in multicarrier (OFDM) communication systems, and efficient modulation and coding techniques (TCM and turbo coding). He spent two years (1979-

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In this thesis, a CMOS 2.4 GHz Low noise amplifier (LNA) and Voltagecontrolled oscillator (VCO) was designed and simulated. These circuits were designed to operate in the 2.4GHz Industrial Scientific Medicine (ISM) band and to achieve Bluetooth and Wifi standard specifications. High-Q RF MEMS air-suspended circular spiral inductors are used in both circuits. High-Q inductors give the circuit better performance parameters including higher gain, lower noise figure and narrower bandwidth. The integration of these RF MEMS inductors onto RF circuit chips was carried out using the UV-LIGA technique and an additive pattern transfer technique such as electroplating. The LNA maintains a gain of 10dB and noise figure of 0.8dB at 2.4 GHz. With an input reflection coefficient of -10.8dB and output reflection iv coefficient of -12.93dB, the LNA matches successfully with 50Ω load at 2.4 GHz. The

A transceiver front-end for 5 GHz wireless local area network applications has been designed and implemented in a low-cost 46 GHz f T pure-silicon bipolar technology. The transceiver front-end adopts a superheterodyne sliding-IF architecture and consists of a down-converter, an up-converter and an LO frequency synthesiser. By exploiting a 1 bit variable-gain low-noise amplifier, the down-converter is able to provide an excellent noise figure of 4 dB while ensuring an input 1 dB compression point of 210 dBm with a current consumption of 25 mA from a 3 V supply voltage. The transmitter front-end is implemented by means of a current-reuse variable-gain up-converter. The circuit provides an output 1 dB compression point of 5.3 dBm although consuming only 45 mA from a 3 V supply voltage. Moreover, a linear-in-dB gain control characteristic is achieved over a 35 dB dynamic range. The LO frequency synthesiser is implemented by means of an integer-N phase-locked loop. It features a phase noise of 2117 dBc/Hz at 1 MHz offset from the centre frequency of 4.1 GHz and exhibits a tuning range of 1.2 GHz, from 3.47 to 4.65 GHz. The LO frequency synthesiser draws 20 mA from a 3 V supply voltage.

A low-noise amplifier, direct-conversion quadrature mixer, power amplifier, and voltage-controlled oscillators have been implemented in a 0.12-m, 200-GHz T 290-GHz MAX SiGe bipolar technology for operation at 60 GHz. At 61.5 GHz, the two-stage LNA achieves 4.5-dB NF, 15-dB gain, consuming 6 mA from 1.8 V. This is the first known demonstration of a silicon LNA at V-band. The downconverter consists of a preamplifier, I/Q double-balanced mixers, a frequency tripler, and a quadrature generator, and is again the first known demonstration of silicon active mixers at V-band. At 60 GHz, the downconverter gain is 18.6 dB and the NF is 13.3 dB, and the circuit consumes 55 mA from 2.7 V, while the output buffers consume an additional 52 mA.

This paper proposes the use of N-push operation for combining the functions of the VCO and divider in the mm-wave frequency range. If employed in a PLL, the combined VCO/divider (C-VCO/D) would potentially provide wider tuning range than traditional mm-wave PLLs employing injection locked frequency dividers, thus exploiting the full range available in the 60 GHz band (57 GHz-64 GHz).

An overview of recent progress in the research and development of micromachined devices for use in wireless communication sub-systems is presented. Among the specific devices described are tunable micromachined capacitors, integrated high-Q inductors, micromachined low-loss microwave and mm-wave filters, low loss micromechanical switches, microscale vibrating mechanical resonators with Q's in the tens of thousands, and miniature antennas for mm-wave applications. Specific applications are reviewed for each of these components with emphasis on methods for miniaturization and performance enhancement of existing and future wireless transceivers.

This paper reviews recent research conducted at the University of Toronto on the development of CMOS transceivers aimed at operation in the 90-170-GHz range. Unique nanoscale CMOS issues related to millimeter-wave circuit design in the 65-nm node and beyond are addressed with an emphasis on transistor and top-level layout issues, low-voltage circuit topologies, and design flow. A Doppler transceiver and two receivers fabricated in a 65-nm GPLP CMOS technology are described, along with a single pole, double throw antenna switch with better than 5-dB insertion loss and 25-dB isolation in the entire 110-170-GHz band. The first receiver has an IQ architecture with a fundamental frequency voltage-controlled oscillator, and is intended for wideband passive imaging applications at 100 GHz. The measured noise figure and downconversion gain are 7-8 and 10.5 dB, respectively, while the 3-dB bandwidth extends from 85 to 100 GHz. The second receiver has double-sideband architecture, operates in the 135-145-GHz range (the highest for CMOS receivers), and features an 8-dB gain LNA, a double-balanced Gilbert cell mixer, and a dipole antenna. The 90-94-GHz Doppler transceiver, the highest frequency reported to date in CMOS, is intended for the remote monitoring of respiratory functions. A Doppler shift of 30 Hz, produced by a slow-moving (4.8 cm/s) target located at a distance of 1 m, was measured with a transmitter output power of approximately +2 dBm and a phase noise of 90 dBc/Hz at 1 MHz offset. The range correlation effect is demonstrated for the first time in CMOS by measuring the phase noise of the received baseband signal at 10-Hz offset, clearly indicating that 1 noise has been canceled and it does not pose a problem in short-range applications, where neither a phase-locked loop nor a frequency divider are needed.

A fast simulation environment has been developed using MATLAB™ and CMEX™ for behavioral level simulation of Delta-Sigma ( ) based Fractional-N PLL frequency synthesizers. The simulator uses a difference equation approach with a uniform time step. To support a uniform time step in the simulation, the continuous-time average current-to-voltage loop filter transfer function is modeled as a discrete-time charge difference-to-voltage transfer function. Simulation results are presented on a type-II fourth-order PLL frequency synthesizer employing a third-order MASH modulator. *

This paper describes the design topologies and considerations of a differential sinusoidal-output digitally controlled crystal oscillator (DCXO) intended for use in cellular applications. The oscillator has a fine-tuning range of 44 ppm, approximately 14 bits of resolution, and an average step size of 0.005 ppm. All signals connecting externally to I/O pins are sine waves for reducing noise, interference, and spurs couplings. The 26 MHz DCXO fabricated in 65 nm CMOS achieves a phase noise of 149.1 dBc/Hz at 10 kHz offset measured at the sine wave buffer output. The DCXO is capable of meeting the stringent phase noise requirements for IEEE 802.11n 5 GHz WLAN devices. A typical frequency pulling of 0.01 ppm due to turning on/off the sine wave buffer is measured. The DCXO dissipates 1.2 mA of current, whereas each sine wave output buffer draws 1.4 mA. The DXCO occupies a total silicon area of 0.15 mm .

We discuss coherent optical orthogonal frequency division multiplexing (CO-OFDM) as a suitable modulation technique for long-haul transmission systems. Several design and implementation aspects of a CO-OFDM system are reviewed, but we especially focus on phase noise compensation. As conventional CO-OFDM transmission systems are very sensitive to laser phase noise a novel method to compensate for phase noise is introduced. With the help of this phase noise compensation method we show continuously detectable OFDM transmission at 25.8 Gb/s data rate (20 Gb/s after coding) over 4160-km SSMF without dispersion compensation.

This paper presents a 60GHz direct-conversion transceiver using 60GHz quadrature oscillators. The 65nm CMOS transceiver realizes the IEEE802.15.3c full-rate wireless communication for every 16QAM/8PSK/QPSK/BPSK mode. The maximum data rates with an antenna built in the package are 8Gb/s in QPSK mode and 11 Gb/s in 16QAM mode within a BER of <;1CH, and the transmitter and the receiver consume 186mW and 106mW, respectively.