Showing papers on "Phase noise published in 1995"
TL;DR: In this contribution the transmission of M-PSK and M-QAM modulated orthogonal frequency division multiplexed (OFDM) signals over an additive white Gaussian noise (AWGN) channel is considered and the degradation of the bit error rate is evaluated.
Abstract: In this contribution the transmission of M-PSK and M-QAM modulated orthogonal frequency division multiplexed (OFDM) signals over an additive white Gaussian noise (AWGN) channel is considered. The degradation of the bit error rate (BER), caused by the presence of carrier frequency offset and carrier phase noise is analytically evaluated. It is shown that for a given BER degradation, the values of the frequency offset and the linewidth of the carrier generator that are allowed for OFDM are orders of magnitude smaller than for single carrier systems carrying the same bit rate. >
1,816 citations
01 Aug 1995
TL;DR: This paper presents a multi-carrier digital modulation technique-orthogonal frequency division multiplexing and the ideas of using a guard interval to accommodate long delay ghosts and of creating spectrum notches to combat co-channel interferences are discussed.
Abstract: This paper presents a multi-carrier digital modulation technique-orthogonal frequency division multiplexing. A review of the technique and its development and implementation are provided. The advantages and disadvantages in comparison to other modulation techniques are also discussed. The ideas of using a guard interval to accommodate long delay ghosts and of creating spectrum notches to combat co-channel interferences, as well as of assigning different order of modulations or power levels to different sub-carriers for layered services are discussed. The effects of phase noise and the peak-to-average power ratio of the OFDM signal are also analysed. >
399 citations
TL;DR: In this paper, a dual-mode multisection distributed feedback semiconductor laser is used to generate high power signals between 40 and 60 GHz with extremely high spectral purity and stability.
Abstract: This paper presents a new approach to the optical generation of millimeter-wave signals using a dual-mode multisection distributed feedback semiconductor laser. This simple device is capable of generating high power signals between 40 and 60 GHz with extremely high spectral purity and stability. The two optical modes produced by this laser are heterodyned on an ultrafast photodiode to give a beat signal at the mode difference frequency. The phase noise of the beat signal is greatly reduced by phase-locking the modes using an electrical drive signal applied to the laser at a subharmonic of the beat frequency. Millimeter-wave signals are obtained with a linewidth of less than 10 Hz, a phase noise of less than -85 dBc/Hz at 100 kHz offset, and a locking range of about 500 MHz. Millimeter-wave fiber-radio systems are seen as a major application area for these new compact optical sources. >
280 citations
TL;DR: In this article, the implementation of two high-frequency building blocks for low-phase-noise 1.8 GHz PLL in a standard 0.7/spl mu/m CMOS process is discussed.
Abstract: The implementation of the two high-frequency building blocks for a low-phase-noise 1.8-GHz frequency-synthesizing PLL in a standard 0.7-/spl mu/m CMOS process is discussed. The VCO uses on-chip bondwires, instead of spiral inductors, for low noise and low power. The design of these bondwire inductors is discussed in great detail. A general formula for the theoretical limit of the phase noise of LC-tuned oscillators is presented. The design of a special LC-tank allows a trade-off between noise and power. The realized VCO has a phase noise of -115 dBc/Hz at 200 kHz from the 1.8-GHz carrier and consumes 8 mA from a 3-V supply. The prescaler has a fixed division ratio of 128 and uses an enhanced ECL-alike high-frequency D-flipflop. Its power consumption is 28 mW.
255 citations
18 Jun 1995
TL;DR: A simple feed-forward correction technique based on pilot cells is proposed, that dramatically reduces the degradation due to phase-noise and allows the design of low-cost tuners through specifying the required phase- noise characteristics.
Abstract: In OFDM transmission schemes, phase-noise from oscillator instabilities in the receiver is a potentially serious problem, especially when bandwidth efficient, high order signal constellations are employed. The paper analyses the two effects of phase-noise: inter-carrier interference (ICI) and a phase error common to all OFDM sub-carriers. Through numerical integration, the ICI power can be evaluated and is shown as a function of the number of OFDM sub-carriers and various parameters of the phase-noise model. Increasing the number of sub-carriers causes an increase in the ICI power, which our analysis indeed shows to become a potential problem, since it can lead to a BER floor. The analysis allows the design of low-cost tuners through specifying the required phase-noise characteristics. A similar technique is applied to calculate the variance of the common phase error. After showing that the common phase error is essentially uncorrelated from symbol to symbol, we propose a simple feed-forward correction technique based on pilot cells, that dramatically reduces the degradation due to phase-noise. This is confirmed by BER simulations of a coded OFDM scheme (proposed for terrestrial transmission of digital television) with 64 QAM.
252 citations
TL;DR: In this paper, a general formula based on the concepts of effective resistance and capacitance is developed, which applies for oscillators using active inductors, and the importance of an inductor with very low series resistance is apparent.
Abstract: Frequency synthesizers used in modern telecommunication systems, such as cellular telephones, need to have very low phase noise. Therefore, in the design of high performance frequency synthesizers using Phase Locked Loops (PLL), the Voltage-Controlled Oscillator (VCO) has become a key issue. The trend towards monolithic Integration poses some major challenges. This paper discusses the phase noise aspects of LC-tuned oscillators. A general formula is developed, based on the concepts of effective resistance and capacitance. The formula also applies for oscillators using active inductors. From these results the importance of an inductor with very low series resistance is apparent. To circumvent the technological limits given by an Inductor's series resistance, a presented enhanced LC-tank can be used to make a trade-off between noise and power.
215 citations
TL;DR: This paper introduces the design of two communication circuits, namely a 1/2 frequency divider and a phase-locked loop, fabricated in a partially scaled 0.1 /spl mu/m CMOS technology.
Abstract: Deep submicron CMOS technologies offer the high speed and low power dissipation required in multigigahertz communication systems such as optical data links and wireless products. This paper introduces the design of two communication circuits, namely a 1/2 frequency divider and a phase-locked loop, fabricated in a partially scaled 0.1 /spl mu/m CMOS technology. Configured as a master-slave circuit, the divider achieves a maximum speed of 13.4 GHz with a power dissipation of 28 mW. The phase-locked loop employs a current-controlled oscillator and a symmetric mixer to operate at 3 GHz with a tracking range of /spl plusmn/320 MHz, an rms jitter of 2.5 ps, and a phase noise of -100 dBc/Hz while dissipating 25 mW. >
199 citations
TL;DR: It is shown that when the resonator possesses a suitable nonlinearity, the phase diffusion due to amplifier noise can be suppressed, allowing one to achieve a long-term phase stability comparable to the ultimate noise limit.
Abstract: Resonators driven into self-oscillation via active feedback often form the basis of clocks and other sensitive measurement instrumentation. The phase stability of such an oscillator is ultimately limited by the noise associated with the resonator's intrinsic losses. However, it is often the case that amplifier noise is the dominant cause of the oscillator's phase diffusion. Here it is shown that when the resonator possesses a suitable nonlinearity, the phase diffusion due to amplifier noise can be suppressed, allowing one to achieve a long-term phase stability comparable to the ultimate noise limit.
167 citations
01 Aug 1995
TL;DR: In this paper, an approach for easy calculation of SNR, independent of carrier numbers, is given, using a plot of the phase noise power density for the calculation, which leads to an improved synthesizer concept.
Abstract: This paper explains the mechanisms that lead to a degradation of an OFDM signal because of the phase noise of the RF oscillators. An approach for easy calculation of SNR, independent of carrier numbers, will be given. This SNR approach uses a plot of the phase noise power density for the calculation. The theoretical results lead to an improved synthesizer concept. Values of SNR and BER will be given for the new synthesizer concept. >
140 citations
TL;DR: A new description of the random phase error shows properties that cannot be obtained through Gaussian error propagation, and it is shown that some advanced systematic-error-compensating algorithms have a disadvantageous effect on therandom phase error.
Abstract: Statistical properties of phase-shift algorithms are investigated for the case of additive Gaussian intensity noise. Based on a bivariate normal distribution, a generally valid probability-density function for the random phase error is derived. This new description of the random phase error shows properties that cannot be obtained through Gaussian error propagation. The assumption of a normally distributed phase error is compared with the derived probability-density function. For small signal-to-noise ratios the assumption of a normally distributed phase error is not valid. Additionally, it is shown that some advanced systematic-error-compensating algorithms have a disadvantageous effect on the random phase error.
107 citations
24 Apr 1995
TL;DR: In this article, an improved digital filtering method for line frequency zero-crossing detectors is proposed, which is a cascade of a median filter and an adaptive sinusoid predictor, followed by up-sampling and interpolation.
Abstract: An improved digital filtering method for line frequency zero-crossing detectors is proposed. The multistage filter efficiently attenuates harmonics, wide-band noise, commutation notches, and other impulsive disturbances without causing any phase shift on the primary sinusoidal waveform. Our novel signal-processing system is a cascade of a median filter and an adaptive sinusoid predictor, followed by up-sampling and interpolation. The three-point median filter effectively removes impulses, and the predictor provides wide-band noise attenuation while compensating for delays in the other processing steps. The predictor adapts to possible line frequency variations within the specified range by changing the set of coefficients, based on an estimate of the instantaneous line frequency. The adaptive approach allows the use of highly selective IIR bandpass predictors.
01 Jan 1995
TL;DR: In this article, two HF components for a full CMOS 1.8 GHz frequency synthesizing PLL, the VCO and prescaler, are realized in a standard 0.7 /spl mu/m CMOS process.
Abstract: The two HF components for a full CMOS 1.8 GHz frequency synthesizing PLL, the VCO and prescaler, are realized. The low-phase-noise oscillator employs bondwires for the high-quality on-chip inductor. A special LC tank design enables an even further reduction of the phase noise. The prescaler uses an enhanced ECL-like CMOS D-flipflop and has a fixed division ratio of 128. The VCO and prescaler are integrated in a standard 0.7 /spl mu/m CMOS process.
TL;DR: Very efficient ultrastable millimetre-wave signal generation using hybrid modelocking of a monolithic distributed Bragg reflector semiconductor laser was demonstrated for the first time in this article.
Abstract: Very efficient ultrastable millimetre-wave signal generation using hybrid modelocking of a monolithic distributed Bragg reflector semiconductor laser is demonstrated for the first time. Unlike conventional hybrid modelocking methods, a low-power (-1 dBm) RF signal is applied to the saturable absorber section of the laser. The detected laser output gives a 34 GHz signal with phase noise >
TL;DR: Cyclic statistics and higher order spectra-based approaches are shown to yield the same frequency estimates and linear or nonlinear cumulant-based algorithms to identify ARMA model parameters for the noises.
Abstract: The problem of concern here is parameter estimation of harmonics in the presence of multiplicative and additive noise. Cyclic statistics are employed to estimate the frequencies and phases, after which the time series is demodulated and cumulants of the noise processes are estimated. The latter are then supplied to linear or nonlinear cumulant-based algorithms to identify ARMA model parameters for the noises. Cyclic statistics and higher order spectra-based approaches are shown to yield the same frequency estimates. Simulation examples illustrate the algorithms. >
TL;DR: In this article, a novel technique for phase detection using three-step spatial phase-shifting interferometry is presented, which overcomes and studies the two main problems presented in the commonly used 3-step phase-stepping technique.
Abstract: A novel technique for phase detection using three-step spatial phase-shifting interferometry is presented. The presented technique overcomes and studies the two main problems presented in the commonly used three-step phase-stepping technique. These problems deal with the leak of carrier frequency in the detected phase and the optimal carrier frequency to obtain the highest phase noise robustness.
Patent•
20 Jan 1995
TL;DR: In this paper, a data transmission system is disclosed which comprises a source of a data signal and a modulator, responsive to the data signal, producing a first modulated signal representing the data signals and a second modulating signal representing a signal (180) out-of-phase with the data messages.
Abstract: A data transmission system is disclosed which comprises a source of a data signal and a modulator, responsive to the data signal, producing a first modulated signal representing the data signal and a second modulated signal representing a signal (180) out-of-phase with the data signal. The first and second modulated signals are transported via a transmission channel. A first demodulator (50, 100) demodulates the transported first modulated signal and a second demodulator (50, 100) demodulates the transported second modulated signal. A subtractor (60, 70), responsive to the first and second demodulators, produces a signal representative of the data signal.
TL;DR: In this approach, SPICE-compatible lumped element RC substrate macromodels are efficiently generated from the circuit layout using a geometric construct called the Voronoi tessellation, and a model topology which automatically adapts itself to the local densities of substrate features associated with the noise coupling is derived.
Abstract: We present a modeling technique for assessing the impact of substrate-coupled switching noise in CMOS mixed-signal circuits. Since the magnitude of the noise problem is a function of the relative proximity of noisy and sensitive devices, design aids are required which can incorporate the switching noise effects at the post-layout phase of design verification. In our approach, SPICE-compatible lumped element RC substrate macromodels are efficiently generated from the circuit layout using a geometric construct called the Voronoi tessellation. The new models retain the accuracy of previously reported models, but contain orders of magnitude fewer circuit nodes, and are suitable for analyzing larger circuits. The node count reduction is realized by deriving a model topology which automatically adapts itself to the local densities of substrate features associated with the noise coupling. Our strategy has been verified using detailed 2-D device simulation, and successfully applied to some mixed-A/D circuit examples.
TL;DR: This paper proposes and demonstrates the use of a fuzzy PLL to estimate the time-varying phase of a sinusoidal signal and shows via simulation results that fuzzy P LL's offer performance comparable to analytically derived PLL's when the phase exhibits high dynamics and high noise.
Abstract: The problem of robust phase-locked loop design has attracted attention for many years, particularly since the advent of the global positioning system. This paper proposes and demonstrates the use of a fuzzy PLL to estimate the time-varying phase of a sinusoidal signal. It is shown via simulation results that fuzzy PLL's offer performance comparable to analytically derived PLL's (e.g. Kalman filters and H/sub /spl infin estimators) when the phase exhibits high dynamics and high noise. The fuzzy PLL rules are optimized using a gradient descent method and a genetic algorithm. >
TL;DR: In this paper, the intensity and phase noise of single-mode laser diodes, either free-running or using different types of line narrowing techniques at room temperature, were investigated.
Abstract: We have investigated the intensity and phase noise of single-mode laser diodes, either free-running or using different types of line narrowing techniques at room temperature, namely feedback from an external grating and injection locking. We have measured an intensity squeezing of 1.2 dB in the first case, and 1.4 dB in the second case (respectively, 1.6 dB and 2.3 dB inferred at the laser output). We have observed that the intensity noise of a free-running 'single-mode' laser diode actually results from a cancellation effect between large anticorrelated fluctuations of the main mode and of weak longitudinal side modes. It is also shown that free-running diodes exhibit very large excess phase noise. Typically more than 80 dB above shot noise at 10 MHz, which can be significantly reduced by the above-mentioned techniques.
TL;DR: In this paper, a voltage comparator-based measuring method is proposed to measure the influence of digital noise on analog circuits using wide-band voltage comparators as noise detectors, which can be further reduced by lowering the digital supply voltage.
Abstract: This paper proposes a method of measuring the influence of digital noise on analog circuits using wide-band voltage comparators as noise detectors. Noise amplitude and r.m.s voltage are successfully measured by this method. A test chip is fabricated to measure the digital noise influence. From the experimental results, it is shown that the digital noise influence can be considerably reduced by using a differential configuration in analog circuits for mixed-signal IC's. The digital noise influence can be further reduced by lowering the digital supply voltage. These results show that the voltage-comparator-based measuring method is effective in measuring the influence of digital noise on analog circuits. >
31 May 1995
TL;DR: In this paper, an advanced phase noise reduction technique was developed to improve the short-term frequency stability of the microwave oscillators, based upon the ultra sensitive microwave frequency discriminator with the effective noise temperature close to its physical temperature.
Abstract: In this paper we report an advanced phase noise reduction technique developed to improve the short term frequency stability of the microwave oscillators. The technique is based upon the ultra sensitive microwave frequency discriminator with the effective noise temperature close to its physical temperature. The frequency discriminator comprises a room temperature sapphire loaded cavity operating on a "whispering gallery" mode with an unloaded Q factor of 185000 at 9 GHz. The phase noise spectral density of the microwave loop oscillator, incorporating such a discriminator as a sensor for the frequency servo, has been measured to be equal to S/sub /spl phi///sup osc/(F)/spl ap/-60-10log/sub 10/(F/sup 3/) dBc/Hz at frequencies below a few kHz. This corresponds to a level of phase noise as low as -120 dBc/Hz and -150 dBc/Hz at offset frequencies 100 Hz and 1 kHz respectively.
TL;DR: In this paper, the authors have developed a commercially-viable high purity X-band signal source incorporating a cryogenic sapphire dielectric resonator, which is of the whispering gallery type to take advantage of the excellent electromagnetic field confinement offered by this geometry.
Abstract: Progress is reported on efforts to develop a commercially-viable high purity X-band signal source incorporating a cryogenic sapphire dielectric resonator. The resonator design is of the whispering gallery type to take advantage of the excellent electromagnetic field confinement offered by this geometry. Complications resulting from the high spurious mode density of this type of resonator have been eliminated by developing a very accurate and complete mode analysis program which fully incorporates the dielectric anisotropies of the sapphire ring. This program allows the design of a window in the frequency domain where no unwanted modes exist, with accurate placement of the desired mode at the center of this region. Preliminary evaluation of the phase noise properties of simple oscillators incorporating these resonators have been performed. For example, in a dual-oscillator comparison of two oscillators operating near 13 GHz phase noise values of L(f)=-55 dBc/Hz, -145 dBc/Hz and -161 dBc/Hz were obtained for offset frequencies of 1 Hz, 1 kHz and 10 kHz, respectively. >
15 Feb 1995
TL;DR: The architecture in this design uses a phase accumulator to address a ROM look-up table that stores the sine samples and has modulation capabilities that include frequency modulation and phase modulation.
Abstract: Direct digital frequency synthesizers (DDFS) play an important role in modern digital communications and instrumentation. They offer many advantages including fast continuous-phase switching response, fine frequency resolution, large bandwidth, good spectral purity, and low phase noise. The architecture in this design uses a phase accumulator to address a ROM look-up table that stores the sine samples. The input word (frequency-control word) to the phase accumulator controls the frequency of the generated sine waveform. This chip has modulation capabilities that include frequency modulation and phase modulation. Frequency modulation is performed by directly modulating the frequency control word and phase modulation is obtained by adding a phase offset to the phase accumulator output before addressing the ROM look-up table. The 7.2/spl times/7.9 mm/sup 2/ 94,000 transistor chip dissipates 3 W at 5 V and 800 MHz.
01 May 1995
TL;DR: The phase noise of monolithic voltage-controlled oscillators is formulated with the aid of a linearized model and a new definition of Q is introduced and three mechanisms leading to phase noise are identified.
Abstract: In this paper, the phase noise of monolithic voltage-controlled oscillators is formulated with the aid of a linearized model. A new definition of Q is introduced and three mechanisms leading to phase noise are identified. A simulation technique using sinusoidal noise components is also described.
TL;DR: In this article, the authors examined the quantum-limited behavior of an electro-optical intensity feedback loop and presented a simple theory and experimental data showing excellent agreement, and showed that although the light incident upon the in-loop detector may be sub-Poissonian, this light has unique properties different from those of a freely propagating beam of intensity squeezed light.
Abstract: We examine the quantum-limited behavior of an electro-optical intensity feedback loop and present a simple theory and experimental data showing excellent agreement We show that, although the light incident upon the in-loop detector may be sub-Poissonian, this light has unique properties different from those of a freely propagating beam of intensity squeezed light We support this by presenting the results of homodyne measurements of the phase noise of light extracted from the loop The utility of the in-loop field is discussed, and it is shown that in all cases in which linear optical components are used, no advantage in signal-to-noise ratio is gained by taking measurements by using this light rather than a coherent source We also discuss effects seen in the extracted or out-of-loop light We demonstrate the existence of, and derive an expression for, an optimum gain for suppressing low-level classical noise Conversely, in the high-gain limit, we demonstrate that the extra noise seen in the out-of-loop photocurrent that is due to the feedback process is expressible purely in terms of the mean photocurrents involved Lastly, we introduce the novel concept of using an intensity feedback loop in conjunction with a squeezed source and show that the feedback loop has the capability of electronically transferring squeezing from one light beam to another
TL;DR: Tight lower and upper bounds on the CRBs themselves are developed, which are intuitively more appealing and easier to implement, which support well-established formulas on the achievable accuracy for estimates of constant amplitude harmonics.
Abstract: The concern here is retrieval of single and multiple tone harmonics observed in white Gaussian multiplicative and additive noise. Computable Cramer-Rao bound (CRB) expressions are derived on the frequency and phase estimates as well as on the sample mean or variance of the multiplicative noise processes. The zero- and nonzero-mean multiplicative noise cases are addressed separately and are shown to yield distinct CRBs on the frequency and phase estimates. Tight lower and upper bounds on the CRBs themselves are developed, which, relative to the CRBs, are intuitively more appealing and easier to implement. Well-established formulas on the achievable accuracy for estimates of constant amplitude harmonics turn put to be special cases of our results. Numerical studies support our claims. >
TL;DR: In this article, an X-band microwave oscillator incorporating a room temperature thermoelectric stabilized sapphire resonator operating at 9.00000 GHz with a Galani type stabilization scheme was measured.
Abstract: The authors report on an X-band microwave oscillator incorporating a room temperature thermoelectric stabilized sapphire resonator operating at 9.00000 GHz. With a Galani type stabilization scheme they have measured a reduced single sideband phase noise of about -124 dBc/Hz at 1 kHz with a f/sup -3/ dependence. The measurement was limited by the flicker noise of the phase detector in the feedback electronics. The frequency stability was also measured; at an integration time of 0.1 seconds a /spl delta/f/f of about 10/sup -11/ with a /spl tau//sup 0.7/ dependence was measured. The frequency drift strongly correlated with ambient temperature fluctuations. >
TL;DR: In this paper, an incoherent receiver for demodulation of signals with random phase in additive impulsive noise modeled as a bivariate isotropic Cauchy process was proposed.
Abstract: We compute an incoherent receiver for demodulation of signals with random phase in additive impulsive noise modeled as a bivariate isotropic Cauchy process. Monte-Carlo simulation clearly shows that the proposed Cauchy receiver has a significantly improved operating characteristic over the corresponding Gaussian receiver. Moreover, the Cauchy receiver is very robust in the entire class of bivariate isotropic symmetric alpha-stable impulsive noises. >
TL;DR: In this article, active probes for on-wafer waveform and network measurements were fabricated for both on-and off-chip NWA ICs and showed step response fall times of 2.7 ps when excited by a 0.7ps falltime input.
Abstract: We have fabricated active probes for on-wafer waveform and network measurements. The probes incorporate GaAs nonlinear transmission line (NLTL) based network analyzer (NWA) integrated circuits and low-loss quartz coplanar-waveguide probe tips. The active probes show step response falltimes of 2.7 ps when excited by a 0.7-ps falltime input, Using these active probes, we demonstrate both waveform measurements with 2.7-ps risetime and network measurements to 200 GHz. We discuss the probe tip and NWA IC design, the hybrid assembly and mechanical design, and system design considerations. On-wafer waveform and S-parameter measurements of monolithic millimeter-wave integrated circuits are demonstrated. >