Showing papers on "Phase noise published in 1982"

Distribution of the Phase Angle Between Two Vectors Perturbed by Gaussian Noise

Abstract: The probability distribution of the phase angle between two vectors perturbed by correlated Gaussian noises is studied in detail. Definite integral expressions are derived for the distribution function, and its asymptotic behavior for large signal-to-noise is found for "small," "near \pi/2 ," and "large" angles. The results are applied to obtain new formulas for the symbol error rate in MDPSK, to calculate the distribution of instantaneous frequency, to study the error rate in digital FM with partial-bit integration in the postdetection filter, and to obtain a simplified expresion for the error rate in DPSK with a phase error in the reference signal. In the degenerate case in which one of the vectors is noise free, the results lead to the symbol error rate in MPSK.

Noise Properties of PLL Systems

Abstract: This is a survey paper which begins by the derivation of the general PLL noise equation and by dividing the additive noises into the passband group and the stopband group. In the following paragraphs the behavior of all the major sources of additive noises is investigated and the practical numerical values of the respective power spectral densities are given. In the terminating sections, guidelines for minimizing the additive noises in PLL systems and PLL frequency synthesizers are emphasized, and finally, phase-noise power spectral densities of several actual PLL frequency synthesizers are plotted in the normalized form. The paper is accompanied by a copious bibliography.

Phase-Locked Loops with Limiter Phase Detectors in the Presence of Noise

Abstract: A nonlinear mathematical model of phase-locked loops with limiter phase detectors in the presence of noise is presented. The model, which is an extension of the well-known baseband model of loops with sinusoidal phase detectors without limiters, incorporates a modified nonlinear phase detector characteristic, the form of which is changed if the input carrier-to-noise ratio alters, as well as a modified phase noise as an input to the model. Both the modified phase detector characteristic and the spectral density of the modified noise term are calculated specifically for sinusoidal, triangular, and sawtooth types of limiter phase detectors, allowing the application of various methods to determine the loop noise performance. As an example, the phase error variance of a first-order phase-locked loop is calculated, thereby showing a strong dependence on the specific phase detector realization.

All-fiber gyroscope with inertial-navigation short-term sensitivity.

Abstract: We report new experimental data for an all-fiber gyroscope with a noise density of 0.004(deg/h)2/Hz. This is compatible with the requirements for inertial navigation. Noise contributions from the coherent Rayleigh backscatter when a phase-modulation bias scheme is used and also from acoustic vibrations are discussed.

High Phase Order - Ready for Application

Abstract: High Phase Order (i. e., more than three phases) overhead lines offer the combined advantages of high power transmission within a narrow right of way, low noise levels, small size leading to attractive appearance, mplete compatibility with three phase systems, and high reliability through resistance to transient faults.

Optimal Detection of Digitally Modulated Signals

Abstract: In this paper optimal detectors are derived and analyzed for the general class of digitally modulated signals in which the sequence of symbols is unknown a priori and information data are not of interest. The detectors test the signal present condition in background white Gaussian noise versus the null condition of noise alone. Particular attention is focused upon cases in which the SNR per symbol is low compared to unity. The models employed herein are sufficiently general to include most forms of spread-spectrum signals as well as other digital type communication signals.

Low frequency noise physical analysis for the improvement of the spectral purity of GaAs FETs oscillators

Abstract: Low frequency (L.F.) noise in GaAs FETs was investigated both theoretically and experimentally. The main contribution to the overall noise at frequencies over 103 Hz was found to be flicker noise generated in the gradual region of the channel. A new simple relationship is proposed to derive the noise voltage intensity referred back to the input at normal operating conditions: it is reported that this noise spectral intensity does not depend on bias voltages for micrometer or submicrometer devices. This relationship provides a fast and easy way for assessing devices for their L.F. noise: an improvement in the spectral purity of GaAs FETs oscillators designed with low L.F. noise FETs is reported.

Characterization of phase noise in semiconductor lasers

Abstract: Phase noise in semiconductor lasers has been investigated by many authors in the range of low frequencies (<1 MHz). In this letter we present for the first time phase noise measurements extended up to frequencies greater than 1 GHz. Experimental results showing the power spectral density Sφ(ω) of the instantaneous frequency φ(t) and the variance σ2[Δτφ(t)] of the phase shift Δτφ(t) are presented. The peculiar behavior of Sφ(ω), which presents a sharp peak at the same frequency of the amplitude noise peak, can account for the excessive broadening of the linewidth of single‐mode injection lasers.

Effect of semiconductor laser phase noise on BER performance in an optical DPSK heterodyne-type experiment

Abstract: We report the first experimental investigation of the effect of laser-diode phase noise on the error-rate performance in a PSK heterodyne differential detection fibre communication experiment. A newly designed AlGaAs laser emitter with adjustable linewidth is used as both the signal carrier and the local oscillator. Error rate is measured for 25 Mbit/s and 50 Mbit/s signals at an intermediate frequency of 250 MHz, and a BER (bit error rate) of 10?10 has been achieved.

Phase-Locked Loop Performance in the Presence of CW Interference and Additive Noise

Abstract: This paper presents the results of an investigation concerning the performance degradation of a phase-locked loop (PLL) due to continuous wave (CW) interference and additive white Gaussian noise The performance measures evaluated include the probability density function (pdf) of phase error and the cycleslipping rate The measures are characterized in terms of the ratio of interference to the desired signal power and the loop signal-to-noise ratio Since the interference term in the loop phase error signal is periodic, the conditional pdf of the phase error process is cyclostationary A Fourier series expansion is applied as an approach to obtain a solution to the cyclostationary process Linear performance results are derived and compared to the analytic results

Means and method for reduction of phase jitter

Abstract: A sinusoidal component of phase jitter in a communications channel is reduced by apparatus including means providing an oscillator signal at the receiver and modifying the received signal phase in accord therewith. Decision means determine the probable transmitted signal and the signals at the input and output of the decision means are compared to determine the residual phase jitter. The residual phase jitter is compared with a suitably delayed oscillator signal and the results of the comparison are used to alter the modification (by the oscillator signal) of the received signal to further reduce the phase jitter. Preferably the results of the comparison are also used to reduce the frequency difference between the oscillator signal and the phase jitter.

Reduction of optical phase noise in semiconductor lasers

Abstract: There are several applications of highly coherent semiconductor lasers, especially in coherent optical-fibre communications systems and optical-fibre sensors. Optical phase noise is extremely important in these applications. Here we report preliminary results from a simple technique whereby phase noise in semiconductor lasers may be reduced. Initial results demonstrate a phase-noise reduction of typically 20 dB. Developments of the technique should permit reduction towards the shot noise limit.

Automotive radio receiver with radio frequency interference elimination circuit

Abstract: An automotive radio receiver with a radio frequency interference elimination includes a noise detector adapted to detect noise in the power source wiring and a circuit for eliminating radio frequency interference noise The detector is physically connected to the power source wiring so that it can satisfactorily detect noise in the power source wiring such as spark ignition noise and switching noise of the automotive electric equipments The noise elimination circuit includes a switch normally closed and responsive to the noise signal produced by the noise detector to open, and a capacitor for holding the radio signal level while the switch is opened and discharging the constant-level signal for reproduction of the radio sound

Analog to digital converter

Abstract: PURPOSE:To suppress the noise of a sampling pulse source mixed into a digital output signal by integrating a parallel processing type A/D converter by adding a frequency dividing circuit which divides an A/D conversion pulse from the sampling pulse source by N. CONSTITUTION:When the frequency of a sampling pulse source connecting with the A/D conversion pulse input terminal 12 of a parallel processing type A/D converter is NfS and phase noise power spectrum density S (f), the output frequency of an integrated N-frequency-dividing circuit 18 is fs and its noise spectrum density is S (f)/N. Pulses with the frequency fS are applied to a comparator group 15 to sample an analog input signal Vin. During the sampling, a noise from the sampling pulse source is added to the signal Vin, but its level is S (f)/ N, thereby suppressing the mixing of the noise into the signal Vin to 1/N.

Analog computer simulation of a Duffing oscillator and comparison with statistical linearization

Abstract: We present the results of an analog computer simulation of a Duffing oscillator, i.e. of a damped anharmonic oscillator with a cubic non-linearity driven by Gaussian white noise. The simulations were performed for wide ranges of parameter values. The experimentally obtained spectral densities are compared with those obtained analytically using the method of statistical linearization.

Microwave frequency synthesizer using plural switchable low noise oscillators

Abstract: Disclosed is a low noise microwave frequency synthesizer having a plurality of rapidly switchable output frequencies. Two banks of oscillators are selectively mixed to yield a range of output signals of low phase noise and low spurious noise. The first bank of oscillators comprises low noise, highly stable oscillators of a frequency range below the desired synthesized output signal. The second bank of oscillators comprises low noise, highly stable oscillators of a frequency range lower than the first bank. The signal from the second bank of oscillators is frequency multiplied to a desired frequency range by a low multiplication factor and then mixed with the signal from the first bank of oscillators. Multiplied phase noise is reduced by using a low multiplication factor. The upper sideband of the mixed signals is output as the synthesized output signal. Rapid switching between oscillators in both banks provides a frequency range of synthesized output signals which may be rapidly stepped through as desired.

FM noise measurement of w-band impatt diodes with a quasi-optical direct detection system

Abstract: A simple and accurate method for determining the FM noise of negative-resistance regenerative oscillators in the microwave region is the so-called direct detection system, where the FM-AM noise conversion is achieved with a discriminator, usually a high Q-factor cavity. With increasing oscillator frequency (above 30 GHz), however, it becomes increasingly difficult to obtain reliable discriminators with high Q-factors. This difficulty can be overcome by applying high-quality quasi-optical resonators for the FM-AM noise conversion.

Digital frequency synthesizer circuit

Abstract: A high-resolution digital pulse to digital pulse divider circuit directly synthesizes precise frequencies having low phase noise content and phase continuity when frequency changes occur.

Correlation of core noise obtained by three signal coherence techniques

Abstract: The prediction of frequency content and noise levels of turbofan engine core noise is reexamined as a result of recent test data and a new diagnostic technique. The diagnostic technique, utilizing a three-signal coherence method, is used to obtain core noise spectra for several engines. Similarities and differences of the spectra are discussed. Finally, the three-signal coherence data are correlated, leading to an improved core noise prediction procedure.

Direct measurement of FM noise in 80 GHz solid-state oscillators

Abstract: A technique for the measurement of FM noise in W-band oscillators is described. The method is ‘direct’, since it makes use of a tuned frequency discriminator operating at the fundamental oscillator frequency. The equipment is compared with other types of noise measurement systems, and the important factors affecting sensitivity are noted. Measurements of the FM noise performance of oscillators utilising GaAs TEOs and Si impatts are presented.

Scattering Matrix Analysis on the Use of a Wide-Band Laser Source in a Passive Fiber Rate Sensor

Abstract: Recent results obtained by various laboratories experimenting with passive fiber optic rotation sensors have suggested that a wide-band laser source, provided it is not so broad that dispersion effects in sensor elements external to the fiber ring, such as the input-output coupler, become significant, can appreciably reduce low frequency random noise at the sensor output. This low-frequency noise is due to the time variation of the elements comprising the fiber ring’s scattering matrix model at a given source wavelength.

Development of Precision SAW Oscillators for Military Applications

Abstract: For the past few years Raytheon has had a program to develop, for potential military applications, SAW oscillators in the 300-600 MHz range which exhibit simultaneously state-of-the-art performance in frequency settability and stability. Though specific applications will not be discussed, the requirements are, in general: (1) The noise floor must be at least -160 dBc/Hz; (2) Vibration sensitivity should be at least as good as that of AT-cut bulk-wave devices; (3) The oscillator frequency must be set in, and stay in, a window of approximately f 10 ppm. In some cases, a warm-up time of less than 3 minutes may be required. Significant progress has been made in meeting these requirements and will be discussed in this paper. In the area of spectral purity, two topics are discussed. The first is a low-noise amplifier which has demonstrated a -176 dBc/Hz noise floor when used with a 310-MHz SAW resonator. Second, the effects of external vibration on noise sidebands are briefly reviewed. One of the most important areas of SAW oscillator development has been that of frequency settability. A trimming technique using gold phase pads has been demonstrated on both delay lines and resonators. Experimental results are presented. One complication that is discussed is the occurrence of a frequency shift during sealing that is on the srder of 100 ppm. However, external pulling techniques have been developed to re-adjust the frequency. Many applications require the use of ovens to maintain a constant temperature. Fast warm-up may then become a requirement, and data is presented to show the frequency stability for a 3-minute warm-up period. Finally, in addition to all of the above requirements, a SAW oscillator must maintain a long-term stability of %l pprn per year. Data is presented to establish baseline aging rates for devices cold-weld-sealed in TO-8 packages and also to show rates for trimmed devices, and devices mounted for low vibration sensitivity.

Noise generator having variable bandwidth and center frequency

Abstract: A noise source is coupled through a first bandpass filter to a first mixer to which a first local oscillator signal is applied. The output of the first mixer is coupled through a second bandpass filter to a second mixer to which a second local oscillator signal is applied. At the output of the second mixer is obtained a noise signal having a bandwidth that can be varied by varying the frequency of the first local oscillator, and having a center frequency that can be varied by varying the frequency of the second local oscillator.

Comparison of AM Noise from a Klystron and an IMPATT Oscillator at Around 90 GHz

Abstract: This paper reports comparisons between the amplitude modulation noise performance of a Plessey IMPATT oscillator AT0273 and a Varian VRB-2113 klystron at millimeter wavelengths.

Influence of microwave phase noise on Josephson voltage steps

Abstract: The influence of microwave phase noise on rf‐induced constant voltage steps generated by the ac Josephson effect is studied. Different circuit models for the junction excitation are considered: dc and rf voltage generators, dc and rf current generators, dc current and rf voltage generators. The analysis has been carried out assuming a power and band limited phase noise modulation in the first two cases, while in the last one a white frequency modulation spectrum is required for a treatment based on the Fokker‐Planck equation. Some experimental results are reported, in order to display the basic phenomenological behavior.

Measuring angular speed with sensitive ring interferometer - uses long coherence duration source and phase noise light modulation

Abstract: Light emitted from the night source can be used to break from the phase relationship between the disturbance light components and the useful light components. The modulation is a phase modulation achieved using an optical modulator (MOD) or using a generator of sound conducted through a solid or air. The modulation causes phase noise in the light which produces an electrical signal in a photodetector (D) whose output is analysed after passing through an electrical filter (TP) whose upper limit frequency is small compared to the reciprocal of the product of 2Pi and the transition time through a static light path (L).

High-noise-rejection fiber-optic probe for interferometric applications.

Abstract: A fiber-optic interferometer with almost total rejection of the noise introduced by the fiber-optic link is reported. The new scheme is based on the passage of the reference and sensing beams through the same path in a single-mode fiber. The experimental results emphasize the excellent noise rejection of the new setup compared with that of a conventional fiber-optic interferometer.