Showing papers on "Phase noise published in 1984"
TL;DR: Detectability of a 400-ms, 1000-Hz pure-tone signal was examined in bandlimited noise where different spectral regions were given similar waveform envelope characteristics, and it was determined that the frequency relation and remoteness of the coherent noise did not particularly influence the magnitude of the unmasking effect.
Abstract: Detectability of a 400-ms, 1000-Hz pure-tone signal was examined in bandlimited noise where different spectral regions were given similar waveform envelope characteristics. As expected, in random noise the threshold increased as the noise bandwidth was increased up to a critical bandwidth, but remained constant for further increases in bandwidth. In the noise with envelope coherence however, threshold decreased when the noise bandwidth was made wider than the critical bandwidth. The improvement in detectability was attributed to a process by which energy outside the critical band is used to help differentiate signal from masking noise, provided that the waveform envelope characteristics of the noise inside and outside the critical band are similar. With flanking coherent noise bands either lower or higher in frequency than a noise band centered on the signal, it was next determined that the frequency relation and remoteness of the coherent noise did not particularly influence the magnitude of the unmasking effect. An interpretation in terms of nonsimultaneous masking was reconciled with some aspects of the data, and with an interpretation in terms of across-frequency temporal pattern analysis. This paradigm, in which detection is based upon across-frequency temporal envelope coherence, was termed "comodulation masking release." Comodulation offers a controlled way to investigate some of the mechanisms which permit signals to be detected at adverse signal-to-noise ratios.
377 citations
01 Jul 1984
TL;DR: In this paper, the authors discuss the implementation of fiber-optic lattice structures incorporating singlemode fibers and directional couplers, and show that the pole of the system transfer function with the largest magnitude is simple and positive-valued (in the Z-plane), and that the magnitude of the frequency response can nowhere exceed its value at the origin.
Abstract: We discuss the implementation of fiber-optic lattice structures incorporating single-mode fibers and directional couplers. These fiber structures can be used to perform various high-speed time-domain and frequency-domain functions such as matrix operations and frequency filtering. In this paper we mainly consider systems in which the signals (optical intensities) and coupling coefficients are nonnegative quantities; these systems fit well in the theory of positive systems. We use this theory to conclude, for example, that for such systems the pole of the system transfer function with the largest magnitude is simple and positive-valued (in the Z-plane), and that the magnitude of the frequency response can nowhere exceed its value at the origin. We also discuss the effects of various noise phenomena on the performance of fiber-optic signal processors, particularly considering the effects of laser source phase fluctuations. Experimental results are presented showing that the dynamic range of the fiber systems, discussed in this paper, is limited, not by the laser source intensity noise or shot noise, but by the laser phase-induced intensity noise. Mathematical analyses of lattice structures as well as additional applications are also presented.
362 citations
01 Jan 1984
TL;DR: In this article, a thorough treatment of phase noise, its relationship to thermal noise and associated subjects such as frequency stability is provided, including the design of low-phase noise signal sources, including oscillators and synthesisers.
Abstract: This book contains a thorough treatment of phase noise, its relationship to thermal noise and associated subjects such as frequency stability. The design of low phase noise signal sources, including oscillators and synthesisers, is explained and in many cases the measured phase noise characteristics are compared with the theoretical predictions. Full theoretical treatments are combined with physical explanations, helpful comments, examples of manufactured equipment and practical tips. Overall system performance degradations due to unwanted phase noise are fully analysed for radar systems and for both analogue and digital communications systems. Specifications for the acceptable phase noise performance of signal sources to be used in such systems are derived after allowing for both technical and economic optimisation. The mature engineer whose mathematics may be somewhat rusty will find that every effort has been made to use the lowest level of mathematical sophistication that is compatible with a full analysis and every line of each mathematical argument has been set out so that the book may be read and understood even in an armchair. Due to a novel approach to the analytical treatment of narrow band noise, the book is simple to understand while simultaneously carrying the analysis further in several areas than any existing publication.
320 citations
TL;DR: In this article, the influence of quantum phase fluctuations which affect single frequency semiconductor lasers in various coherent detection systems is discussed in terms of photocurrent autocorrelation and spectral density functions.
Abstract: The influence of quantum phase fluctuations which affect single frequency semiconductor lasers in various coherent detection systems is discussed in terms of photocurrent autocorrelation and spectral density functions. The general treatment given in this paper can be applied in diverse practical cases and points out the problems of phase correlation and phase matching between the two mixed optical beams. In the more general case the photocurrent spectrum is found to be composed of discrete and quasi-Lorentzian parts whose energies and spectral spreads are discussed as a function of the laser line width, the phase matching and the phase correlation between the two coherently combined fields.
203 citations
TL;DR: In this article, an expression for the probability of error in an optical heterodyne DPSK system, subject to shot noise and quantum phase noise of the optical sources, is derived for the maximum linewidth of the transmit and local optical sources to satisfy a given degradation in optical receiver sensitivity.
Abstract: An expression is derived for the probability of error in an optical heterodyne DPSK system, subject to shot noise and quantum phase noise of the optical sources. Results are given for the maximum linewidth of the transmit and local optical sources to satisfy a given degradation in optical receiver sensitivity.
125 citations
Book•
30 Jun 1984
TL;DR: This book discusses the relationship between phase jitter and noise density, the quadrature representation of narrowband noise, and the reciprocal relationships between phase noise and frequency stability.
Abstract: * Chapter 1: Introduction * Chapter 2: Review of modulation theory * Chapter 3: The relationship betweenphase jitter and noise density * Chapter 4: Noise induced frequency modulation * Chapter 5: Noise in oscillators * Chapter 6: Frequency multiplier chains * Chapter 7: The use of phase lock loops * Chapter 8: Frequency synthesisers * Chapter 9: The reciprocal relationships between phase noise and frequency stability * Chapter 10: System phase noise requirements * Appendix 1: Summary of important formulae * Appendix 2: Noise figure review * Appendix 3:The quadrature representation of narrowband noise * Appendix 4: The Q of varactor tuned oscillators * Appendix 5: The phase noise performance of Gunn oscillators
121 citations
01 Jan 1984
TL;DR: In this paper, a Kalman Filter model is used to estimate and predict clock phase, frequency and frequency drift. But the model is not suitable for the measurement of phase as a function of time rather than as a spectral density.
Abstract: A relationship was constructed between the Allan variance parameters (H sub z, H sub 1, H sub 0, H sub -1 and H sub -2) and a Kalman Filter model that would be used to estimate and predict clock phase, frequency and frequency drift. To start with the meaning of those Allan Variance parameters and how they are arrived at for a given frequency source is reviewed. Although a subset of these parameters is arrived at by measuring phase as a function of time rather than as a spectral density, they all represent phase noise spectral density coefficients, though not necessarily that of a rational spectral density. The phase noise spectral density is then transformed into a time domain covariance model which can then be used to derive the Kalman Filter model parameters. Simulation results of that covariance model are presented and compared to clock uncertainties predicted by Allan variance parameters. A two state Kalman Filter model is then derived and the significance of each state is explained.
120 citations
TL;DR: In this paper, the authors derived the modulation and noise properties of a semiconductor laser consisting of an active cavity loaded by a passive cavity and showed that under certain conditions the direct modulation bandwidth can be doubled with simultaneous phase noise reduction as compared to a conventional laser.
Abstract: We derive the modulation and noise properties of a semiconductor laser consisting of an active cavity loaded by a passive cavity. The results indicate that under certain conditions the direct modulation bandwidth can be doubled with simultaneous phase noise reduction as compared to a conventional laser.
101 citations
01 Jan 1984
TL;DR: In this article, Voise sidebands and Spectral densties of phase fluctuations in the Freguency Domain were used to measure phase noise in the frequency domain.
Abstract: I INTRODKTI~N II FUNDAMENTAL CONCEPT A Voise Sidebands B Spectral Denstty C Spectral Denstries of Phase Fluctuations in the Freguency Domain D Modulation Theory and Spectral Density Relationships E Noise Processes F Integrated Phase Noise G AU Noise tn the Frequency Domain III PHASE-NOISE MEASUREMENTS USING THE TWO-OWLLATOR TECHNIQUE A TWO NOISY Oscrllators B Automated Phase-Noise Measurements Using the Two-Oscillator Technique C Calibration and Measurements Using the Two-Oscillator S,vstem IV SINGLE-OSCILLATOR PHASE-NOISE MEASUREMENT SYSTEMS AND TECHNIQUES A The Delay Line as an FM Discriminator B Calibration and Measurements Using rhe Delay Line as an FM Discriminator C Dual DelayLine Discriminator D MillimeterWace Phase-Noise Measurements REFERENCE 355 157
92 citations
TL;DR: In this article, the authors present an analysis of a low-noise dielectric resonator GaAs FET oscillator in a frequency-locked loop (FLL), which is used for FM noise degeneration.
Abstract: This paper presents an analysis of a low-noise dielectric resonator GaAs FET oscillator in a frequency-locked loop (FLL), which is used for FM noise degeneration. In this circuit, one resonator serves both as the frequency-determining element of the oscillator and as the dispersive element of the discriminator. The results of the analysis are used to generate design guidelines. These guidelines were followed in an experimental realization of an X-band circuit. The measured FM noise was--120 and--142 dBc/Hz at 10- and 100-kHz offset frequencies, respectively, and corresponded closely to predicted results.
86 citations
TL;DR: In this article, the Burshtein equation was used to obtain an exact expression for the two-level atom's steady-state resonance fluorescence spectrum, when the exciting laser exhibits phase telegraph noise.
Abstract: We discuss strong laser-atom interactions that are subjected to jump-type (random telegraph) random-phase noise. Physically, the jumps may arise from laser fluctuations, from collisions of various kinds, or from other external forces. Our discussion is carried out in two stages. First, direct and partially heuristic calculations determine the laser spectrum and also give a third-order differential equation for the average inversion of a two-level atom on resonance. At this stage a number of general features of the interaction are able to be studied easily. The optical analog of motional narrowing, for example, is clearly predicted. Second, we show that the theory of generalized Poisson processes allows laser-atom interactions in the presence of random telegraph noise of all kinds (not only phase noise) to be treated systematically, by means of a master equation first used in the context of quantum optics by Burshtein. We use the Burshtein equation to obtain an exact expression for the two-level atom's steady-state resonance fluorescence spectrum, when the exciting laser exhibits phase telegraph noise. Some comparisons are made with results obtained from other noise models. Detailed treatments of the effects ofmly jumps, or as a model of finite laser bandwidth effects, in which the laser frequencymore » exhibits random jumps. We show that these two types of frequency noise can be distinguished in light-scattering spectra. We also discuss examples which demonstrate both temporal and spectral motional narrowing, nonexponential correlations, and non-Lorentzian spectra. Its exact solubility in finite terms makes the frequency-telegraph noise model an attractive alternative to the white-noise Ornstein-Uhlenbeck frequency noise model which has been previously applied to laser-atom interactions.« less
TL;DR: In this paper, the effects of self-phase modulation (an optical wave acting on itself) and cross phase modulation (one optical wave modulating a channel at a different wavelength) on the nonlinear refractive index of silica is analyzed.
Abstract: Phase noise in angle-modulated optical-fiber communication systems arising from optical power fluctuations is analyzed. The nonlinear refractive index of silica is the physical mechanism which converts power fluctuations into phase fluctuations. The effects of self-phase modulation (an optical wave acting on itself) and cross-phase modulation in wavelength-division multiplexed (WDM) systems (one optical wave modulating a channel at a different wavelength) have been calculated. The phase noise generated in single-channel systems is negligible for laser fluctuations less than 1-mW rms. In WDM systems containing as few as four channels the phase noise exceeds tolerable levels (0.15 rad) for power fluctuation of 1 mW in each channel.
01 Jan 1984
TL;DR: In this article, the authors present a method for directly measuring the phase noise in a SAW resonator (or any other linear circuit element) at or near its resonant frequency.
Abstract: The most significant contribution of SAW resonators is in the frequency control of low phase noise oscillators at UHF frequencies Techniques for measuring the phase noise of oscillators are well known, but the contribution to that phase noise of the frequency determining element is usually estimated or found by indirect methods We present a method for directly measuring the phase noise in a SAW resonator (or any other linear circuit element) at or near its resonant frequency The correlation between the phase noise measured in a SAW resonator by this method and that measured in an oscillator containing this device is excellent The single-sideband noise spectrum contributed by SAW resonators is found to follow a l/fy trend away from the measurement frequency, where Y is close to 1
TL;DR: Very long baseline interferometry (VLBI) experiments at a frequency of 89 GHz (3.4mm wavelength) using hydrogen maser frequency standards show that under good atmospheric conditions coherence can be maintained for times up to 700 s, corresponding to an Allan standard deviation of approximately 10−14 as discussed by the authors.
Abstract: Very long baseline interferometry (VLBI) experiments at a frequency of 89 GHz (3.4-mm wavelength) using hydrogen maser frequency standards show that under good atmospheric conditions coherence can be maintained for times up to 700 s, corresponding to an Allan standard deviation of approximately 10−14. The stability appears to be largely limited by the phase noise resulting from fluctuations in delay through the troposphere. Methods of estimating the interferometer fringe amplitudes and closure phases in the presence of large phase fluctuations are examined. The spectrum and the Allan standard deviation of the observed phase fluctuations are derived.
01 Jan 1984
TL;DR: In this article, an analytical model for oscillator noise resulting from active device LF noise is presented and applied to a number of GaAs MESFET oscillators finding good quantitative agreement, and demonstrating several ways of reducing the phase noise.
Abstract: An analytical model for oscillator noise resulting from active device LF noise is presented. We apply it to a number of GaAs MESFET oscillators finding good quantitative agreement, and demonstrating several ways of reducing the phase noise. We show evidence that after having reduced the effect of the normally dominant device LF noise source, a residual LF noise source starts to dominate the phase noise. The best phase noise result for the 5GHz oscillators is S/sub phi/(1kHz) = -75dB/Hz.
TL;DR: A fundamental lower bound on the linearized mean-square phase and time delay errors resulting from a practical synchronizer operating on a carrier-modulated PAM waveform which is corrupted by stationary Gaussian noise is derived.
Abstract: In this paper we derive a fundamental lower bound on the linearized mean-square phase and time delay errors resulting from a practical synchronizer operating on a carrier-modulated PAM waveform which is corrupted by stationary Gaussian noise. Our bound applies to a large class of synchronizers and, unlike the linearized performance itself, it is easily evaluated from the modulation format, the baseband PAM pulse shape, the additive noise spectrum, and the synchronizer's closedloop transfer function matrix.
TL;DR: In this article, an improved method of calculating the linewidth of a laser oscillator due to phase noise is proposed, where the fluctuation in the output amplitude that leads to the phase diffusion is calculated as the amplified thermal and the quantum noise which are delta-correlated in time.
Abstract: An improved method of calculating the linewidth of a laser oscillator due to phase noise is proposed. The fluctuation in the output amplitude that leads to the phase diffusion is calculated as the amplified thermal and the quantum noise which are delta-correlated in time. The saturated gain distribution along the cavity axis that is consistent with the output coupling at the end surfaces is taken into account in calculating the amplification of the noises. The resulting linewidth formula differs somewhat from the conventional formula.
TL;DR: In this paper, the effect of optical feedback on the intensity noise spectrum and the longitudinal mode line shape of a 1.55μm InGaAsP laser was investigated for reflections arising from the far end of a 7.5km-long fiber.
Abstract: The effect of optical feedback on the intensity‐noise spectrum and the longitudinal‐mode line shape of a 1.55‐μm InGaAsP laser is investigated for reflections arising from the far end of a 7.5‐km‐long fiber. The intensity noise near the relaxation‐oscillation frequency is significantly enhanced by the reflection feedback. Owing to the intercavity coupling, the enhancement is, however, frequency dependent and the noise spectrum exhibits high‐contrast modulations with a period corresponding to the fiber‐cavity longitudinal‐mode separation. A simple rate equation model is used to explain the observed behavior.
TL;DR: It is found that the optimum compensation deconvolution technique uses an adaptive filtet with the passbands coinciding with the frequency bands of the signal, thus optimizing noise filtration, while the Guillaume-Nahman technique utilizes a low-pass filter for all signals.
Abstract: The performance of two iterative frequency-domain deconvolution techniques, the optimum compensation and the Guillaume-Nahman, is evaluated. The study involved the characterization of the adaptive filters utilized to reduce the deconvolution noise. Comparisons between the two techniques are performed for various classes of signals having different levels of acquisition noise. It is found that the Guillaume-Nahman technique is potentially more accurate but more sensitive to acquisition noise. It is also found that the optimum compensation deconvolution technique uses an adaptive filtet with the passbands coinciding with the frequency bands of the signal, thus optimizing noise filtration, while the Guillaume-Nahman technique utilizes a low-pass filter for all signals.
TL;DR: In this article, the Langevin equation is used to estimate the phase of an injection-locked laser oscillator in the limit of complete inversion and zero internal loss of the laser resonator, and the associated uncertainty is twice that dictated by the uncertainty principle.
Abstract: The quantum noise of an injection-locked laser oscillator is analyzed by the operator Langevin equation. The problem is also treated by the Fokker-Planck equation and the same results are obtained in the same regimes of applicability. The steady-state solution of the Fokker-Planck equation gives the probability distribution of amplitude and phase, the Langevin equation arrives more directly at the spectrum of amplitude and phase. The phase of the injection-locked oscillator is related to the phase of the injection signal and thus constitutes a measurement of phase. In the limit of complete inversion and zero internal loss of the laser resonator, the associated uncertainty is twice that dictated by the uncertainty principle. This result is interpreted by comparing it with the uncertainty introduced by a linear amplifier which can perform a simultaneous measurement of amplitude and phase.
01 Jan 1984
TL;DR: In this paper, the problem of I/f FM noise reduction in GaAs MESFET oscillators from circuit design considerations is addressed with the aid of an analytic model that includes in-band and upconversion expressions Variations in these terms are investigated as a function of circuit impedance.
Abstract: This paper addresses the problem of I/f FM noise reduction in GaAs MESFET oscillators from circuit design considerations The near-carrier FM noise is described with the aid of an analytic model that includes in-band and upconversion expressions Variations in these terms are investigated as a function of circuit impedance In particular, the bias impedance is observed to significantly affect the FM noise of the oscillator, primarily through the upconversion process Techniques for noise reduction and experimental results are presented
TL;DR: Phase-modulated single-sideband detection is applied to a fiber gyroscope using the Sagnac phase to provide a high dynamic range and first experimental results are reported.
Abstract: Phase-modulated single-sideband detection is applied to a fiber gyroscope. The Sagnac phase is linearly transposed into the phase of an electrical low-frequency signal by using an integrated-optic phase modulator, which is driven by a proper modulating waveform. This detection scheme can provide a high dynamic range. The principle and first experimental results are reported.
TL;DR: In this article, the phase noise characteristics of single mode semiconductor laser with optical feedback have been studied and a correlation was found between the suppression of the low frequency noise and the enhancement of the high frequency noise near the relaxation oscillation frequency.
Abstract: The phase noise characteristics of single mode semiconductor lasers with optical feedback have been studied. A correlation is found between the suppression of the low‐frequency noise and the enhancement of the high‐frequency noise near the relaxation oscillation frequency. Contrary to previous analyses, the low‐frequency noise is minimized when the reflected light is 70°–90° out of phase with respect to that inside the diode laser cavity. A calculation of the laser frequency fluctuation spectrum, taking into account the amplitude‐phase coupling of the laser field, agrees with the observation. A new explanation is proposed for the feedback‐induced phase noise reduction effect.
TL;DR: Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer and image-intensifier structure noise was shown to be a dominant noise source in unsubtracted images at medium to high radiation exposure levels.
Abstract: The sources of noise in a digital video subtraction angiography system were identified and analyzed. Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer. The major sources of noise include quantum noise, TV camera electronic noise, quantization noise from the analog-to-digital converter, time jitter, structure noise in the image intensifier, and video recorder electronic noise. A new noise source was identified, which results from the interplay of fixed pattern noise and the lack of image registration. This type of noise may result from image-intensifier structure noise in combination with TV camera time jitter or recorder time jitter. A similar noise source is generated from the interplay of patient absorption inhomogeneities and patient motion or image re-registration. Signal-to-noise ratios were measured for a variety of experimental conditions using subtracted digital images. The measured signal-to-noise ratios were found to fluctua...
Patent•
16 Feb 1984TL;DR: In this paper, a low noise oscillator is described suitable for use in an AM stereo radio receiver, which includes means for controlling its amplitude at a constant low level, and is amenable to electronic tuning and IC construction.
Abstract: A low noise oscillator is described suitable for use in an AM stereo radio receiver. The oscillator circuit includes means for controlling its amplitude at a constant low level. The oscillator is amenable to electronic tuning and IC construction.
01 Jan 1984
TL;DR: In this article, a low noise GaAs FET oscillator circuit is presented, which uses a single dielectric resonator both in the oscillator feedback circuit and as the dispersive element of a discriminator in a frequency locked loop used for noise degeneration.
Abstract: A low noise GaAs FET oscillator circuit is presented. It uses a single dielectric resonator both in the oscillator feedback circuit and as the dispersive element of a discriminator in a frequency locked loop used for noise degeneration. An FM noise level of -120 dBc/Hz at 10 kHz offset was measured at X-band.
TL;DR: In this paper, it was shown experimentally that low-frequency noise in an oscillator normally produces two LF noise sidebands around the center frequency f 0 of the oscillator.
Abstract: Low-frequency noise in an oscillator normally produces two LF noise sidebands around the center frequency f_{0} of the oscillator. It was shown experimentally that these noise sidebands can be eliminated by using an oscillator circuit with an odd-symmetrical characteristic. A simple theory based on the van der Pol approach to oscillators can explain the observed effects.
TL;DR: It is shown that, from a practical standpoint, conventional DPSK gives the optimum performance of any offset scheme, and out-performs symmetric DPSK by an order of magnitude and more in error rate when the noise correlation becomes significant.
Abstract: The bit error rate performance of binary DPSK with an arbitrary offset of the phase change vector is derived in the presence of noise correlation and power imbalance, and the special cases of conventional DPSK (0 phase change offset) and symmetric DPSK ( \pi/2 phase change offset) are compared. Precise conditions are given for optimum offsets, and it is shown that, from a practical standpoint, conventional DPSK gives the optimum performance of any offset scheme, and outperforms symmetric DPSK by an order of magnitude and more in error rate when the noise correlation becomes significant. It is also found that performance improvement over conventional DPSK can be realized, provided the noise correlation is known, by making the bit decision regions in phase space unequal, thereby demonstrating that the MAP estimator for DPSK without correlation is no longer optimum when the noise is correlated.