Showing papers on "Phase noise published in 1971"
TL;DR: In this paper, the spectral analysis using least squares (LS) is further developed to remove any undesired influence on the spectrum, which can be used for irregularly spaced as well as equidistantly spaced data.
Abstract: The concept of spectral analysis using least-squares is further developed to remove any undesired influence on the spectrum. The influence of such a ‘systematic noise’ can be eliminated without the necessity of knowing the magnitudes of the noise constituents. The technique can be used for irregularly spaced as well as equidistantly spaced data. The response to random noise is found to be constant in the frequency domain and its expected level is derived. Presence of random noise in the analyzed time series is shown to transform the spectrum merely linearly. Examples of applications of the technique are presented.
298 citations
TL;DR: This work has constructed and tested a laser interferometer transducer for a long, wideband, laser-linked gravitational radiation antenna and measured the smallest vibrational displacement measured directly with a laser to date.
Abstract: We have constructed and tested a laser interferometer transducer for a long, wideband, laser-linked gravitational radiation antenna. Photon-noise-limited performance was achieved using 80 microW from a single mode Spectra-Physics 119 laser in a modified Michelson interferometer on a vibration isolation table in a quiet room. A piezoelectric driver on one of the interferometer mirrors was used to generate subangstrom (3 x 10(-14)-m) vibrations of known amplitude. The measured displacement sensitivity of the system in the kilohertz region was 1.3 x 10(-14)m/Hz(1/2), which compares well with the calculated photon noise limit of 1.06 x 10(-14) m/Hz(1/2). This is the smallest vibrational displacement measured directly with a laser to date.
134 citations
TL;DR: In this paper, radio noise measurements made near overhead power lines from 2.4 to 345 kV in the frequency range of 60 Hz to 1 GHz and on radio noises measurements made on 7.2, 345, 525, 735, and 765kV ac lines and on an 800-kV dc test line up to 10 GHz.
Abstract: This paper presents radio noise measurements made near overhead power lines from 2.4 to 345 kV in the frequency range of 60 Hz to 1 GHz and on radio noise measurements made on 7.2, 345, 525, 735, and 765-kV ac lines and on an 800-kV dc test line up to 10 GHz. The measurements and their analysis show the important radio noise factors involved in the development and use of prediction techniques for the evaluation of communication site performance in the vicinity of overhead power lines.
73 citations
TL;DR: In this article, it was shown that the relationship between the output and input signal-to-noise ratio may be significantly different than that obtained by Davenport for incoherent limiters.
Abstract: Many applications of the bandpass limiter (BPL) involve coherent demodulation following the limiter. It is shown that as a result of demodulation, the signal mean and the noise variance are direct functions of the phase angle between the signal component passed by the BPL and the coherent reference. As a result, the relationship between the output and input signal-to-noise ratio may be significantly different than that obtained by Davenport for incoherent limiters. A study is also made of the output noise spectral density, and an approximate expressison is derived as a function of the input signal-to-noise ratio, reference phase angle, and the characteristics of the input bandpass filter to the limiter. Also discussed is the first-order signal-plus-noise probability density following coherent demodulation.
52 citations
TL;DR: In this paper, the results of experimental and theoretical investigations of the noise characteristics of lMPATT diode amplifiers and oscillators are presented. But the experimental results are in good agreement with the theoretical predictions.
Abstract: The results of experimental and theoretical investigations of the noise characteristics of lMPATT diode amplifiers and oscillators are presented. The oscillator noise is shown to consist of three different contributions: modulation noise, selectively amplified primary noise, and conversion noise. The influence of the active device nonlinearity and load circuit parameters is discussed in detail. The experimental results are in good agreement with the theoretical predictions. It is especially pointed out that the large correlation between AM and FM fluctuations, usually measured in IMPATT oscillators, indicates nonoptimum AM noise performance. Experimental techniques for achieving optimum AM noise performance are demonstrated (orthogonal noise tuning). By a simple extension of the model, the noise behavior of an injection phase-locked oscillator can be described. The calculated AM and FM noise power spectra for the synchronized oscillator are also shown to be in good agreement with experimental results. Finally the signal-to-noise ratio for current modulated IMPATT oscillators is investigated and optimization is demonstrated.
46 citations
TL;DR: A useful and mathematically rigorous method is presented for exactly evaluating the error-probability performance of a binary differentially coherent phase-shift-keyed (DPSK) system in the presence of both thermal noise and intersymbol interference.
Abstract: In this paper a useful and mathematically rigorous method is presented for exactly evaluating the error-probability performance of a binary differentially coherent phase-shift-keyed (DPSK) system in the presence of both thermal noise and intersymbol interference. The channel filter and the receiver input signal-to-noise ratio are assumed to be given. This method suggests, first, to calculate the probability of error induced by both the thermal noise and the large interfering samples whose normalized amplitudes with respect to noise standard deviation are greater than unity, and then, to add the correction terms due to the presence of the other intersymbol interference samples. If the normalized interference amplitudes with respect to the noise standard deviation are less than unity (although the total interference power may still be greater than total noise power), then this method simply becomes that which first evaluates the error probability induced by thermal noise alone and then adds the correction terms due to the presence of intersymbol interference. For numerical computations, various recurrence relations are developed so that the probability of error can be easily obtained on a digital computer. These relations have been utilized in an example to calculate the performance of certain practical PSK and DPSK systems.
26 citations
01 Jan 1971
TL;DR: In this paper, the authors presented a power-noise characterization of a phase-locked IMPATT oscillator with respect to the output power and the corresponding FM noise in a range of operating conditions and showed that the best performance for each type of diode was obtained when operated at less than maximum power and at reduced efficiency.
Abstract: IMPATT diode characterization on the basis of output power and the corresponding FM noise figure over a range of operating conditions is presented. The characterization consists of families of power noise curves obtained for a phase-locked IMPATT oscillator where the supply current, load conductance, and the operating frequency are parameters. It is shown that the maximum output power and minimum FM noise are not achieved concurrently. In particular FM transmitter application, it is shown that the best performance for each type of diode was obtained when operated at less than maximum power (and at reduced efficiency) where the system benefits from the attending lower noise. Better system performance, this application, was obtained with the GaAs IMPATT diode. The power-noise characterization defines the optimum operating conditions for an IMPATT diode and provides a valid basis for the comparison of diodes for specific applications.
26 citations
TL;DR: In this paper, the output of a differentially coherent detector using the phase of the k th previous bit as a reference is derived under noise free conditions for binary differential phase shift keyed signals, where k = 1, 2, 3 ... or ally integer.
Abstract: In this paper, the output of a differentially coherent detector using the phase of the k th previous bit as a reference is derived under noise free conditions for binary differential phase shift keyed signals, where k = 1, 2, 3 ... or ally integer. This is then related to the output of a conventional differentially coherent detector ( k = 1 ). In the presence of noise, this output relationship changes depending on which detector has made an error in detection. This property can be used to reduce the error rate for differentially coherent systems. A receiver consisting of a first-order (conventional) and second-order detectors, where the references are the phase of the previous and second previous bits, respectively, is analyzed theoretically. The result shows that the amount of improvement in error rate due to the addition of the second-order detector depends on the percentage of single errors in the conventional detector. If the error rate of a conventional differentially coherent system is close to the optimum, the theoretical improvement using the additional detector is small (≃ 0.2 dB). However, it is shown experimentally that if the original performance is poor due to intersymbol interference, then considerable improvement is possible with an additional detector (≃ 1.6 dB). In addition to error rate improvement, the circuit also provides error rate information that can be used for in-service performance monitoring and as a sensor for automatic equalizers.
23 citations
TL;DR: In this paper, the pull-in performance of second-order PLL with a pulse-type (sawtooth) phase comparator was investigated and several circuit implementations were discussed in detail.
Abstract: Phase-locked loops (PLL) with pulse-type (sawtooth) phase comparators find many applications in digital transmission systems. In this paper, the results available on the pull-in performance of the second-order PLL with sawtooth phase comparator are summarized. Then a generalized phase comparator, called a phase-and-frequency comparator, is shown to improve PLL acquisition performance significantly. Several circuit implementations are discussed in detail.
20 citations
TL;DR: A system for identifying an object, and in particular a vehicle, by analyzing the noise spectrum emitted thereby to determine thebasic noise characteristic thereof and then comparing the basic noise spectrum signal with known basic noise spectra.
Abstract: A system for identifying an object, and in particular a vehicle, by analyzing the noise spectrum emitted thereby to determine the basic noise characteristic thereof and then comparing the basic noise spectrum signal with known basic noise spectra. The noise from the object, which includes both the basic noise characteristic and other superimposed noise, is detected and converted to an electrical analog signal which is then sampled. The sampled electrical signal, preferably after passing through an analog to digital converter, is sequentially converted into its orthogonal components in the frequency domain, e.g. by means of a Fourier conversion, converted into a signal with the logarithms of the noise spectrum components, and then reconverted into a signal of the noise spectrum components in the time domain, e.g. an inverse Fourier conversion. The resulting vector signal, which has a course which monotonously decays from an initial high value followed by a rise to a second relative maximum, is gated so that only the portion thereof prior to the rise which portion represents the basic noise characteristic of the object, is passed to a device for comparing this signal with stored signals representing the basic noise characteristic of known objects.
17 citations
TL;DR: In this paper, a linearized theory for the signal and noise characteristics of a marginal oscillator NMR spectrometer has been developed, which modifies Watkins' theory to include the mixing of 1/f noise into the oscillator passband.
Abstract: A linearized theory for the signal and noise characteristics of a marginal oscillator NMR spectrometer has been developed. The model modifies Watkins' theory to include the mixing of 1/f noise into the oscillator passband. Signal response, noise spectrum, signal‐to‐noise ratio, and noise figure are all calculated and compared with accurately calibrated experimental data. The calculated signal response (absolute) is within 12% of experiment. The results show that there are two distinct regions of spectrometer operation, one in which the noise spectrum is white and one in which the noise spectrum is dominated by 1/f mixer noise. In the region of predominately white noise, the calculated noise factor is 2.9 for our circuit, compared with the experimental value of 3.3. Guidelines for optimum selection of rf level and modulation frequency are presented.
26 Apr 1971
TL;DR: In this article, the authors report an advance of more than ten decibels in the state-of-the-art for high quali ty rs 5 MHz quar tz c rys in the no ise frequency range of 1 to 100 Hz.
Abstract: There are several aspects of electronic circuit design which must be carefully considered in order to achieve high short-term frequency stabil i ty in quartz crystal osci l la tors . W e report an advance of more than ten decibels in the state-of-the-art for high quali ty rs 5 MHz quar tz c rys ta l osc i l la tors in the no ise frequency range of 1 to 100 Hz. The most important design fac tors were A) measurement and selection of transistors for the lowest possible f l icker of phase noise' (oscillating loop and buffer stages), B) measurement and selection of transistors and diodes for the lowest possible DC flicker noise (voltage regulators, automatic gain control) , C) massive negative feedback (DC and RF) in the RF c i rcu i t ry to s tab i l ize the RF ga in and to reduce the f l icker of phase noise of the transistors ' (automatic gain control [AGC ] amplifier, buffer amplifiers, oscil lating loop amplifier) . Because more negative feedback is used in the ACC amplifier and in the buffer amplifiers than can be used in the oscil lating loop amplifier, the resultant f l icker of phase noise performance of the osci l la tor is determined by the flicker of phase noise of the t rans is tor in the oscillating loop.
TL;DR: By combining the oscillator-biascircuit equation with Kurokawa's expressions for radiofrequency noise, a general theory of r.f. noise, up-converted (or modulation) noise and downconverted noise and their mutual relationships is developed.
Abstract: By combining the oscillator-bias-circuit equation with Kurokawa's expressions for radio-frequency noise, a general theory of r.f.(or intrinsic) noise, up-converted (or modulation) noise and down-converted noise and their mutual relationships is developed. Special applications to the IMPATT-diode oscillator are discussed.
TL;DR: In this article, a model for the flicker component of the noise is presented, which allows one to find the range of validity for the usual formal calculations for the sample variance of the counted frequency.
Abstract: The phase-error variance of a phase-locked loop is dependent on the stability of its voltage-control oscillator and that of the source oscillator being tracked. Statistics relative to oscillator stability are commonly gathered by counted-frequency techniques and are so specified in manufacturers' data. In order thus to predict the performance of a loop using such an oscillator, it is necessary to know how to relate counter data to loop error. This paper presents such a method based on a simple but realistic model of oscillator noises and shows that the mean sample variance of the counted-frequency method converges rather curiously and slowly to the actual variance. The model for the flicker component of the noise is physically realistic (finite power) and allows one to find the range of validity for the usual formal calculations for the sample variance of the counted frequency. In addition, insight is gained into the relation between the sample variance and the actual finite variance of the realistic model. The effect of oscillator instability on a first-order loop is longterm steady-state phase-error drift and short-term zero-mean fluctuation about this steady state. For the second-order loop, the steady-state drift disappears.
TL;DR: In this article, a single-loop method of phase locking up to 100 GHz is described, where the frequency broadening observed in harmonic mixing with an HCN laser at 891 GHz with resolution 1 in 108 is attributed to phase noise and modulation on the base-reference quartz-crystal oscillator.
Abstract: A single-loop method of phase locking up to 100 GHz is described. Spectral broadening observed in harmonic mixing with an HCN laser at 891 GHz (with resolution 1 in 108) is attributed to phase noise and modulation on the base-reference quartz-crystal oscillator. Zero beats at 99 GHz between klystrons phase-locked to a common reference give frequency resolution of the order of 1 in 1013.
TL;DR: A new method for determining the number of spikes per second, and hence the threshold carrier-to-noise ratio (CNR), of the phase-locked-loop demodulator is presented and is applicable when nonwhite noise is present at the input of the demodulators and also when the carrier is frequency modulated.
Abstract: A new method for determining the number of spikes per second, and hence the threshold carrier-to-noise ratio (CNR), of the phase-locked-loop demodulator is presented. This technique can also be applied to the frequency demodulator with feedback. This method is applicable when nonwhite noise is present at the input of the demodulator and also when the carrier is frequency modulated. Computer processing is employed so that rapid comparisons of the phase-locked-loop (PLL) systems can be made. The results show the spikes per second and the threshold CNR, without modulation, for the first-, second-, and third-order PLL and FM discriminator. Experimental results are then presented.
Patent•
IBM1
TL;DR: In this paper, a carrier recovery method and apparatus for generating a carrier having the proper frequency, relative phase and phase jitter to accurately demodulate a modulated signal having phase jitters is presented.
Abstract: A carrier recovery method and apparatus for generating a carrier having the proper frequency, relative phase and phase jitter to accurately demodulate a modulated signal having phase jitter The phase jitter is detected with minimal distortion and modulated onto a carrier signal generated by means of phase locked oscillators
TL;DR: In this paper, the correlation of the modes is found mathematically and compared with approximations discussed in the literature, and its practical importance is most evident for unsymmetrical corona conditions, as they may exist on double-circuit ac and dc lines.
Abstract: Modal components are customarily used in transmission line radio noise calculations [1-4]. Complete modal transformation [5] produces attenuation and phase constants (losses and velocities of propagation) within the modes. In order to fully utilize this technique, the frequently adopted assumption of random phase relation between the modes at the point of recombination is replaced by a more exact approach in this paper. The correlation of the modes is found mathematically and compared with approximations discussed in the literature [3, 4]. To the authors' knowledge, the analysis presented here closes a gap in the literature on the subject. Its practical importance is most evident for unsymmetrical corona conditions, as they may exist on double-circuit ac and dc lines, and wherever the contributions from the phases shall be calculated separately.
TL;DR: In the presence of impulsive noise, DPSK systems have, for the same SNR, an error rate which is nearly twice the error rate obtained for PSK, so that a considerable improvement in SNR is required to improve performance.
Abstract: A method previously presented by the authors for the evaluation of error probabilities in digital systems when impulsive noise is the main cause of incorrect decisions is here applied to differential phase-shift keying (DPSK) modems. Specifically, the receiver impulsive characteristic, which is proportional to the error rate, is evaluated for binary DPSK systems both in the linear and hard-limited modes of operation. Two encoding systems are considered, in-phase encoding and quadrature encoding, and it is shown that they yield essentially the same performance, at least when the binary symbols are equally likely. The results are compared with the performance of phase-shift keying (PSK) and it is found that, in the presence of impulsive noise, DPSK systems have, for the same SNR, an error rate which is nearly twice the error rate obtained for PSK. However, the dependence of error rate on SNR is generally a slowly decreasing function so that a considerable improvement in SNR is required to improve performance.
TL;DR: A simple procedure for obtaining the variance of the phase noise of photographic film, assuming gaussian statistics and statistical independence between grain and phase noise, is furnished.
Abstract: It is known that the diffraction of coherent light can be used for various spatial-noise measurements including the power-spectrum estimation of photographic emulsions. A number of such measurements are presented. The power spectrum of grain noise is compared with several theoretical models. The spectra of grain and phase noise for overexposed film are obtained. A simple procedure for obtaining the variance of the phase noise of photographic film, assuming gaussian statistics and statistical independence between grain and phase noise, is furnished.
TL;DR: An analytical relationship for the output-spectrum width of a low-level-operating IMPATT-diode oscillator is verified experimentally by measuring relevant diode and circuit quantities as well as the oscillator noise as mentioned in this paper.
Abstract: An analytical relationship for the output-spectrum width of a low-level-operating IMPATT-diode oscillator is verified experimentally by measuring relevant diode and circuit quantities as well as the oscillator noise. Good agreement between theory and experiment is found if the spectrum width is assumed to be predominantly due to f.m. noise.
01 Aug 1971
TL;DR: In this article, a nonlinear theory of noise in a Read diode which takes account of the coupling between low and high frequencies has been developed, and the components of the driving noise voltage of the diode, in phase and out of phase with the signal, have unequal values and are correlated.
Abstract: A nonlinear theory of noise in a Read diode which takes account of the coupling between low and high frequencies has been developed. At high levels, the components of the driving noise voltage of the diode, in phase and out of phase with the signal, have unequal values and are correlated.
TL;DR: In this paper, the authors describe the addition of noise to a microwave carrier by a rocket-exhaust jet in terms of a simple quantitative model of incoherent volume scattering by the turbulent discontinuities in the jet.
Abstract: It has been found possible to describe the addition of noise to a microwave carrier by a rocket-exhaust jet in terms of a simple quantitative model of incoherent volume scattering by the turbulent discontinuities in the jet. The power scattered is spread throughout the noise spectrum by the variation with position in the jet of the magnitude of the mean gas-velocity vector. Comparison between computer calculation and experimentally determined amplitude and phase noise data is found to be excellent.
TL;DR: The phase model for the generalized multifilter phaselock loop (M PLL) is considered and state equations for this model are derived and a linear analysis is presented to aid in the preliminary design of an M PLL and to indicate the noise improvement over a conventional phase-lock loop.
Abstract: The phase model for the generalized multifilter phaselock loop (M PLL) is considered and state equations for this model are derived. A linear analysis is presented to aid in the preliminary design of an M PLL and to indicate the noise improvement over a conventional phase-lock loop (PLL). Performance characteristics are examined for an M PLL with low-pass and bandpass characteristics used in a specific FM communication system. Both single and double sinusoidal FM are used and a region of proper operation of the M PLL is determined in terms of modulation index and modulating frequency. These results are obtained from both analog and digital computer simulation of the nonlinear system.
TL;DR: The mean time to first slip is displayed graphically as a function of signal-to-noise ratio (SNR) for various static phase error offsets and values of the damping parameter.
Abstract: Static phase error offsets occur in first-order and passive second-order phase-locked loops, whenever the rest frequency of the local oscillator and the carrier are different prior to acquisition. The effect of the offset is to degrade performance and in particular to decrease the mean time to first slip. This paper studies first slip times via computer simulation. The mean time to first slip is displayed graphically as a function of signal-to-noise ratio (SNR) for various static phase error offsets and values of the damping parameter.
01 Aug 1971
TL;DR: In this paper, a simple calculation for the amplitude fluctuations and their bandwidth of a Read diode oscillator operating at intermediate power levels is given, and applied to a typical GaAs diode yields a noise-to-signal ratio, -138 dB.
Abstract: A simple calculation is given for the amplitude fluctuations and their bandwidth of a Read diode oscillator operating at intermediate power levels. Application of the model to a typical GaAs diode yields a noise-to-signal ratio, -138 dB, which agrees with recent measurements on abrupt vapor-grown junctions.
Patent•
18 Nov 1971TL;DR: In this article, a low phase noise frequency divider is proposed, comprising a gating arrangement which supplies selected portions of an input reference signal to a tuned circuit without any phase noise due to the gating action.
Abstract: A low phase noise frequency divider is disclosed comprising a gating arrangement which supplies selected portions of an input reference signal to be divided to a tuned circuit without any phase noise due to the gating action. The arrangement which in one embodiment consists of a FET is connected to the tuned circuit input to short out the input except when the input reference signal amplitude crosses ground level in a positive direction and a gate enabling signal is present at the gate electrode of the FET. The gate-enabling signal alone does not decouple the tuned circuit input from ground, therefore phase noise, due to the leading and trailing edges of each gate-enabling signal, is substantially eliminated.
TL;DR: In this article, general expressions for the amplitude and frequency noise of steady-state oscillators are obtained. And the nmr signal-to-noise ratio in the am and fm modes are then calculated.
Abstract: General expressions are obtained for the amplitude noise and frequency noise of steady-state oscillators. The nmr signal-to-noise ratios in the am and fm modes are then calculated. It is found that fm detection of nmr signals is insensitive to 1/f oscillator noise. Some measurements of noise and signal-to-noise ratio are reported and are shown to be in agreement with theory.
TL;DR: In this article, a theory is developed to account for the observed ratio of f.m. noise and current noise in a cavity-controlled Gunn effect oscillator, where the noise processes are assumed to have their origin in spontaneous fluctuations in the carrier concentration of the GaAs layer which give rise to a modulation of the Gunn diode impedance.
Abstract: A theory is developed to account for the observed ratio of f.m. noise and current noise in a cavity-controlled Gunn effect oscillator. The noise processes are assumed to have their origin in spontaneous fluctuations in the carrier concentration of the GaAs layer which give rise to a modulation of the Gunn diode impedance. The principal parameters of interest in the study are device current and domain capacitance both of which are functions of the carrier concentration n and the internal field F of the GaAs layer.In order to estimate the relative contribution of the two terms in the expression derived for fluctuation in the device an analysis is made of the fluctuation mechanisms in terms of the zero-diffusion model of a propagating domain. It is concluded that the term representing the effect of internal field fluctuations makes only a minor contribution to the f.m. noise and current noise. Experimental evidence is produced in support of the theoretical study and an estimate is made of the carrier concentration fluctuation.
TL;DR: In this paper, the noise in the detector plane of an optical data-storage system with Fourier-transform holograms is investigated. But the authors assume that the storage material is Gaussian-probability dense.
Abstract: Calculations are performed to study the noise in the detector plane of an optical data-storage system with Fourier-transform holograms, caused by noise in the storage material. The signal-to-background ratio (SBR) and the signal-to-noise ratio (SNR) of the output signals in the detector plane are defined and calculated. Exact solutions are obtained by assuming gaussian-probability densities for amplitude and phase noise in the storage material.