Showing papers on "Phase noise published in 1996"

Optoelectronic microwave oscillator

Abstract: We describe a novel oscillator that converts continuous light energy into stable and spectrally pure microwave signals. This optoelectronic microwave oscillator consists of a pump laser and a feedback circuit including an intensity modulator, an optical fiber delay line, a photodetector, an amplifier, and a filter. We develop a quasi-linear theory and obtain expressions for the threshold condition, the amplitude, the frequency, the line width, and the spectral power density of the oscillation. We also present experimental data to compare with the theoretical results. Our findings indicate that the optoelectronic microwave oscillator can generate ultrastable, spectrally pure microwave reference signals up to 75 GHz with a phase noise lower than -140 dBc/Hz at 10 kHz.

A study of phase noise in CMOS oscillators

Abstract: This paper presents a study of phase noise in two inductorless CMOS oscillators. First-order analysis of a linear oscillatory system leads to a noise shaping function and a new definition of Q. A linear model of CMOS ring oscillators is used to calculate their phase noise, and three phase noise phenomena, namely, additive noise, high-frequency multiplicative noise, and low-frequency multiplicative noise, are identified and formulated. Based on the same concepts, a CMOS relaxation oscillator is also analyzed. Issues and techniques related to simulation of noise in the time domain are described, and two prototypes fabricated in a 0.5-/spl mu/m CMOS technology are used to investigate the accuracy of the theoretical predictions. Compared with the measured results, the calculated phase noise values of a 2-GHz ring oscillator and a 900-MHz relaxation oscillator at 5 MHz offset have an error of approximately 4 dB.

A 900 MHz CMOS LC-oscillator with quadrature outputs

Abstract: The local oscillator (LO) in a wireless transceiver satisfies many exacting requirements. A variable frequency enables a phase-locked loop (PLL) to servo the LO to a stable lower frequency reference, or to correct frequency errors from measurements on the received signal. A low phase noise ensures little interference with nearby channels. A large LO voltage-swing means that it can drive a mixer with greater linearity. Finally, in single-sideband applications, the LO must supply precise quadrature phases. Low phase noise mandates use of a high-Q resonator to tune the LO, although most RF resonators are usually not integrable on ICs. Quadrature outputs are usually derived from RC phase-shift of a single-phase LO output, but this is susceptible to component inaccuracy and loss in LO amplitude. The authors present a 900 MHz oscillator circuit implemented in 1 /spl mu/m CMOS that affords modestly low-phase noise, has variable frequency with large output swing, and provides quadrature-phase outputs from two identical coupled oscillators, connected in such a way that they exert a mutual squelch when their relative phase is not in quadrature. The coupled oscillators synchronize to exactly the same frequency, in spite of mismatches in their resonant circuits.

Optoelectronic oscillator for photonic systems

Abstract: We describe a novel photonic oscillator that converts continuous-light energy into stable and spectrally pure microwave signals. This optoelectronic oscillator (OEO) consists of a pump laser and a feedback circuit including an intensity modulator, an optical-fiber delay line, a photodetector an amplifier, and a filter. We present the results of a quasi-linear theory for describing the properties of the oscillator and their experimental verifications. Our findings indicate that the OEO can generate ultrastable, spectrally pure microwave-reference signals up to 75 GHz with a phase noise lower than -140 dBc/Hz at 10 KHz. We show that the OEO is a special voltage-controlled oscillator with an optical-output port and can be synchronized to a reference source by means of optical injection locking, electrical injection locking, and a phase-locked loop. Other OEO applications include high-frequency reference regeneration and distribution, high-gain frequency multiplication, comb frequency and pulse generation, carrier recovery, and clock recovery.

Chromatic dispersion in fiber-optic microwave and millimeter-wave links

Abstract: The influence of chromatic fiber-dispersion on the transmission distance of fiber-optic microwave and millimeter-wave links is analyzed and discussed in this paper. It is shown that dispersion significantly limits the transmission distance in intensity modulated direct detection links operating in the above 20 GHz frequency region by inducing a carrier to noise penalty on the transmitted signal. At 60 GHz, a 1 dB penalty is induced after less than 500 m transmission over standard single-mode fiber with a dispersion of 17 ps/km/spl middot/nm and the signal is completely extinct after 1 km. In remote heterodyne detection links, the dispersion induces both a carrier to noise penalty and a phase noise increase on the transmitted signal. It is shown, however, that the induced carrier to noise penalty is insignificant. At 60 GHz, the induced penalty is less than 0.3 dB after 100 km transmission. The phase noise increase proves more dominant. At 60 GHz, a 150 Mbit/s QPSK signal is limited to around 10 km of transmission.

Optical Fiber Communication Systems

Abstract: The Communications Toolbox: Introduction. Probability and Random Variables. Some Important Probability Distributions. Signals and Systems. Random Processes. Spectral Analysis. Narrowband Signals and Systems. Elements of Detection Theory. From Light to Signals. Basic Optical Fiber Communications Components: Introduction. The Refractive Index and the Laws of Reflection and Refraction. Total Internal Refraction. Step Index Fibers and Slab Waveguides. Maxwell's Equations in the Slab Waveguide. Even Propagation Modes. Odd Propagation Modes. Number of Modes and Single-Mode Fibers. Phase Velocity. Group Velocity. Attenuation and Dispersion. Dispersion-Shifted and Dispersion-Flattened Fibers. Polarization-Maintaining and Single-Polarization Fibers. The P-N Junction. Single Heterostructure. Double Heterostructure. LED Physical Structure. The LED Rate Equation. LED Output Spectrum. LED Modulation Response. The Fabry-Perot Resonator. Semiconductor Laser Physical Structure. Laser Output Spectrum--Spectral Width and Linewidth. Bragg Reflections. Distributed Feedback (DFB) and Distributed Bragg Reflection (DBR) Lasers. Rate Equations. The Steady-State Solution to the Rate Equations. Laser Modulation--Step Response. Laser Modulation--Sinusoidal Frequency Response. Relative Intensity Noise (RIN), Phase and Frequency Noise, Chirp. Laser Package. The PIN Photodiode. The Avalanche Photodiode, ADP. Basic Binary Optical Communication System: Introduction. System Description. Performance Evaluation. Coherent Systems: Motivations and Basics. Fundamental Receiver Sensitivity--Homodyne Systems. Heterodyne Systems--Synchronous Detection. Heterodyne Systems--Asynchronous Detection. Heterodyne Systems--Weakly Synchronous Detection. Summary and Comparison of Fundamental Sensitivities. Optical Hybrids. Phase Noise and Linewidth. Synchronous Systems. Asynchronous Systems. Weakly Synchronous Systems. How to Deal with Phase Noise--Summary. Polarization Fluctuations. Appendix A--Statistics of Phase Noise to Amplitude Conversion. Appendix B--Evaluation of Averages by Quadrature Rules. Optical Amplifiers: Introduction. Semiconductor Amplifiers. Erbium-Doped Fiber Amplifier. Comparison of Major SOA and EDFA Characteristics. Other Fiber Amplifiers. Soliton Systems: Intuitive Explanation of Solitons. Advantages of Solitons for Long Distance Transmission. Derivation of Solitons. Amplitude, Duration, Energy, and Power. Higher-Order Solitons. Qualitative Physical Explanation of Solitons. Estimation of Peak Pulse Power Required for Solitons. Fiber Loss and its Compensation. Lumped Amplifiers in Soliton Systems. Polarization Dispersion. Amplified Spontaneous Emission Noise in Soliton Systems. Error Rates in Soliton Systems. Soliton Experiments. Using Recirculating Loops. Wavelength Division Multiplexing with Solitons. Bidirectional Soliton Systems. Sources of Soliton Pulses. Beyond the Gordon-Haus Limit. Multichannel Systems: Introduction. Time-Division Multiplexing (TDM). Wavelength-Division Multiplexing. Subcarrier Multiplexing. Code-Division Multiplexing. Space-Division Multiplexing. Network Issues.

Improving an OFDM reception using an adaptive Nyquist windowing

Abstract: This paper explains how a windowing of the OFDM-signal in the time domain contributes to its improved reception. The windowing uses the part of the guard interval that is not disturbed by multipath reception. The length of the window adapts to the transmission conditions. This window may be realized with a raised cosine or other kind of function that fulfils the Nyquist criterion. An easy way to implement the windowing while keeping the FFT complexity low is also shown. The impact of windowing for discrete sine spurious, white noise, phase noise and frequency deviations is also given. OFDM is of interest in terrestrial broadcasting.

Converting light into spectrally pure microwave oscillation.

Abstract: We present theoretical and experimental results for a novel oscillator that converts continuous light energy into stable and spectrally pure microwave signals. This optoelectronic oscillator can generate ultrastable spectrally pure microwave reference frequencies as high as 75 GHz with a phase noise lower than 2140 dBcyHz at 10 kHz, independent of oscillation frequency.

Principles of Lightwave Communications

Abstract: Light Propagation in Optical Fibres Optical Waveguides Dispersion and Attenuation in Optical Waveguides Optical Detection Theory Optical Receivers Heterodyne Systems Modes in Cylindrical Waveguides Delay and Dispersion in Linear Systems Shot Noise Bounds and Approximations Saddlepoint Approximation Optimal Linear Receivers DPSK Receiver Phase Noise.

Multi-Loop opto-electronic microwave oscillator with a wide tuning range

Abstract: A versatile photonic radio frequency (RF) oscillator employs multiple feedback loops of different delay times, including at least one optical feedback loop, to generate RF signals with ultra low phase noise, narrow spectral linewidth, and a continuous wide tuning range of high resolution. Specifically, an electro-optical modulator and a long optical fiber loop are implemented in one dual-loop system. In addition, a light beam from a light source can be directly modulated by using feedback signals from multi feedback loops to alter the electrical control signal to the light source. Furthermore, the disclosed system supports both electrical and optical RF outputs. External optical injection and electrical injection can be implemented.

Ultrahigh-speed clock recovery with phase lock loop based on four-wave mixing in a traveling-wave laser diode amplifier

Abstract: A new phase lock loop (PLL) is proposed and demonstrated for clock recovery from an ultrahigh-speed time-division multiplexed (TDM) optical signal. A traveling-wave laser-diode amplifier (TW-LDA) is used as a phase detector, and the cross-correlation component between the optical signal and an optical clock pulse train is detected as a four-wave-mixing (FWM) signal generated in the TW-LDA. A timing clock from a TDM signal is extracted as a prescaled electrical clock, and this prescaled clock is directly recovered from a randomly modulated TDM optical signal. A prescaled 6.3 GHz clock is successfully extracted from a 100 Gb/s signal using the timing comparison output obtained as the cross-correlation between the optical signal and a short (<10 ps) 6.3 GHz optical clock pulse train in the generated FWM light. A comparison of the PLL phase noise with a previously reported gain modulation method is also shown, and the possibility of the Tbit/s operation of this PLL is also considered in the experiments.

Time-domain non-Monte Carlo noise simulation for nonlinear dynamic circuits with arbitrary excitations

Abstract: A time-domain, non-Monte Carlo method for computer simulation of electrical noise in nonlinear dynamic circuits with arbitrary excitations and arbitrary large-signal waveforms is presented. This time-domain noise simulation method is based on results from the theory of stochastic differential equations. The noise simulation method is general in the following sense. Any nonlinear dynamic circuit with any kind of excitation, which can be simulated by the transient analysis routine in a circuit simulator, can be simulated by our noise simulator in time-domain to produce the noise variances and covariances of circuit variables as a function of time, provided that noise models for the devices in the circuit are available. Noise correlations between circuit variables at different time points can also be calculated. Previous work on computer simulation of noise in electronic circuits is reviewed with comparisons to our method. Shot, thermal, and flicker noise models for integrated-circuit devices, in the context of our time-domain noise simulation method, are discussed. The implementation of this noise simulation method in a circuit simulator (SPICE) is described. Two examples of noise simulation (a CMOS inverter and a BJT active mixer) are given.

Residual modeling in music analysis-synthesis

Abstract: In analysis-synthesis of musical sounds based on a sinusoidal model, the difference between the original signal and the synthesized signal, termed the residual, is typically a broadband noise process. It contains such musical phenomena as flute breath noise or violin bow noise. Synthesis without such "noise" tends to sound artificial; it is desirable to improve the synthesis realism by modeling the residual in such a way that it can be reinjected in the synthesized signal. This paper deals with a model of noise perception based on the equivalent rectangular bands (ERBs) of the auditory system. Since a broadband noise is perceptually well-represented by the time-varying energy in each of these frequency bands, the residual is parametrized in terms of these energies in the proposed model. An application of the model to music synthesis based on the inverse fast Fourier transform (FFT) is described in detail.

A photonic-link millimeter-wave mixer using cascaded optical modulators and harmonic carrier generation

Abstract: Efficient frequency conversion into and out of the millimeter wave frequency band has been demonstrated using photonic link signal mixing with cascaded optical modulators. By adjusting the modulator bias point and RF drive power to the modulator introducing the local oscillator signal at f/sub LO/=8.8 GHz, frequency conversions from f/sub s/ to f/sub LO//spl plusmn/f/sub s/, sf/sub LO//spl plusmn/f/sub s/, and 4f/sub LO//spl plusmn/f/sub s/ with respective losses of 4.8, 6.3, and 7.5 dB have been demonstrated. The direct phase noise measurement of the optical RF signal at 2f/sub LO/=17.6 GHz with 1 kHz offset shows -89 dBc/Hz, limited by the RF drive source.

Microwave signal generation with optical injection locking.

Abstract: Two single-mode laser diodes have been injection locked to the +1 and −1 diffracted orders of a 4.6-GHz acousto-optical modulator. The measured locking bandwidth was 3 GHz for a locking gain of 35 dB. The microwave signal at 9.2 GHz had a measured linewidth of less than a few hertz. We used this system to drive stimulated Raman transitions between the cesium ground-state hyperfine levels. We observed Ramsey fringes and used them to characterize the microwave signal phase noise.

On-board phase and modulus calibration of large aperture synthesis radiometers: study applied to MIRAS

Abstract: On-board calibration of bidimensional aperture synthesis radiometers with a large number of antennas by the standard correlated noise injection method is technologically very critical because of the stringent requirements on mass, volume, and phase equalization of the noise distribution network. A novel approach, which makes use of a set of uncorrelated noise sources uniformly distributed in the array, is proposed. Each noise source drives correlated noise only to a small set of adjacent antennas. These sets of antennas are overlapped in order to maintain phase and modulus track along the array. This approach reduces drastically mass and volume of the noise distribution network. Moreover, its phase matching requirement is strongly relaxed because it is only necessary within small sets of adjacent antennas. Power stability of the uncorrelated noise sources is also not a stringent requirement. This procedure allows independent phase and modulus calibration by making use of a reduced number of redundant correlations.

A 3 V 4 GHz nMOS voltage-controlled oscillator with integrated resonator

Abstract: There is increasing interest in implementing the key components of radio transceivers in mature silicon technologies. Submicron CMOS technology combined with low-parasitic on-chip passives is emerging as a strong candidate to implement many of these components that traditionally have been realized using GaAs. Fully-monolithic voltage-controlled oscillators (VCOs) present many challenges to any technology since they require low-parasitic high-quality passives for acceptable tuning range and phase noise levels, and low-power active devices at microwave frequencies. A 1.8 GHz CMOS VCO with a 4.5% tuning range is not fully monolithic, as it requires bonding wires as inductive elements in the tank circuit. Fully-integrated LC resonators offer the advantages of low cost and reduced sensitivity to packaging parasitics at the price of lower resonator Q values due to the losses in on-chip spiral inductors and varactor diodes. The authors present a fully-monolithic VCO based on an nMOS gain stage and an integrated tunable resonator operating at 4 GHz with a 9% tuning range. The technology is a 5-level metal 0.5 /spl mu/m BiCMOS process (BiCMOS4S+). No bipolar devices are used in the active circuitry.

A region growing algorithm for InSAR phase unwrapping

Abstract: A region growing algorithm for InSAR phase unwrapping is presented. Initial experiments show that the region growing phase unwrapping algorithm can handle SAR interferograms which are more noisy than other unwrapping algorithms can handle. This algorithm also allows dense fringes caused by steep topography.

A stereo multi-bit /spl Sigma//spl Delta/ D/A with asynchronous master-clock interface

Abstract: An oversampling DAC that generates low-jitter, synchronous and oversampled clock internally uses an on-chip digital phase-locked loop (DPLL) and a digital sample-rate converter to decouple the DAC conversion rate from the audio sample rate. This allows the DAC to be driven by an independent low-jitter clock source that minimizes jitter-induced amplitude errors. The DAC uses a second-order /spl Sigma//spl Delta/ modulator in combination with a 17-level quantizer to achieve greater than 110 dB theoretical SNR and reduced out-of-band noise relative to higher-order 1b modulators. The problem of severe element matching in multi-bit DACs is addressed by applying a data-directed scrambling technique on the thermometer-decoded modulator output that modulates DAC element mismatch errors out of band.

Ultra-low-noise microwave oscillator with advanced phase noise suppression system

Abstract: An advanced phase noise reduction technique has been developed to improve the short-term frequency stability of microwave oscillators. The technique is based upon an ultrasensitive microwave frequency discriminator with effective noise temperature close to its physical temperature. The phase noise spectral density of a 9 GHz microwave loop oscillator incorporating such a discriminator has been measured as -120 dBc/Hz and -150 dBc/Mz at offset frequencies of 100 Hz and 1 kHz, respectively. This performance is at least 25 dB better than current state of the art. The developed phase noise reduction technique is quite general and can have valuable implications for the design of various low phase noise microwave oscillators.

Novel FMCW radar system concept with adaptive compensation of phase errors

Abstract: A new high-performance FMCW sensor system concept is presented The approach is based on an adaptive signal processing scheme compensating phase errors caused by VCO phase noise as well as the non-linearity of the frequency modulation The key component of the low-cost sensor is a SAW (surface acoustic wave) delay line representing a miniaturised high-precision radar reference path A correction algorithm equalises the target signal according to the phase errors simultaneously measured with the reference path Employing this method, an excellent range resolution as well as a high dynamic range and multi-target selectivlty is obtained, which has been experimentally demonstrated at millimetrewave frequencies

System and method for suppressing noise in digitally represented voice signals

Abstract: A noise suppressor that increases a signal to noise ratio of time domain audio data and a method of increasing such signal to noise ratio. The noise suppressor includes: (1) frequency domain transformation circuitry that transforms a frame of the time domain audio data into a frequency domain, (2) noise background modeling circuitry, coupled to the domain transformation circuitry, that spectrally analyzes the frame to model an estimated noise background spectrum thereof, (3) a frequency domain suppression filter, coupled to the noise background modeling circuitry, that filters at least some of the noise background spectrum from the frame and (4) time domain transformation circuitry, coupled to the frequency domain suppression filter, that transforms the frame back into a time domain, the transformed frame having an increased signal to noise ratio.

Effect of carrier phase noise and frequency offset on the performance of multicarrier CDMA systems

Abstract: Kaiser (1995) showed that OFDM-CDMA outperforms DS-CDMA in radio fading channels in terms of spectral efficiency, under the assumption of ideal carrier recovery and chip synchronization. However, residual carrier frequency offset and phase noise degrade the system performance significantly if suitable countermeasures are not taken. In this work we consider the downlink of a cellular multicarrier CDMA system. In particular, we evaluate the impact of the carrier frequency offset and Wiener phase noise on the system performance considering typical indoor radio channels. Moreover, a frequency detector is used to reduce the impairment produced by the carrier frequency offset. Results are given in terms of BER obtained by means of simulations and analytical computations.

Low phase noise millimeter-wave frequency sources using InP-based HBT MMIC technology

Abstract: A family of millimeter-wave sources based on InP heterojunction bipolar transistor (HBT) monolithic microwave/millimeter-wave integrated circuit (MMIC) technology has been developed. These sources include 40-GHz, 46-GHz, 62-GHz MMIC fundamental mode oscillators, and a 95-GHz frequency source module using a 23.8-GHz InP HBT MMIC dielectric resonator oscillator (DRO) in conjunction with a GaAs-based high electron mobility transistor (HEMT) MMIC frequency quadrupler and W-band output amplifiers. Good phase noise performance was achieved due to the low 1/f noise of the InP-based HBT devices. To our knowledge, this is the first demonstration of millimeter-wave sources using InP-based HBT MMIC's.

Noise measurement test system

Abstract: A noise measurement test system 10' for making phase noise and amplitude noise measurements of microwave signals derived from a continuous wave RF source. The system 10' comprises an RF input for receiving an applied RF noise signal and an RF coupler 11 coupled to the RF input for splitting the applied RF noise signal into first and second paths 18a, 18b. A mixer 15 that comprises a synchronous phase detector 15 is coupled to receive signals from the first and second paths 18a, 18b, respectively, and which outputs demodulated phase noise. The first path 18a comprises a variable attenuator 14 and a variable phase shifter 13 coupled between the coupler 11 and the first input of the mixer 15 for providing a reference signal input to the synchronous detector 15. The second path 18b comprises a delay line and an adjustable RF carrier nulling circuit 30 coupled between the coupler 11 and the mixer 15. A video amplifier is coupled to an output of the mixer 15 for providing a baseband video output signal from the system 10' that is processed to produce noise data.

A 1.8-GHz low-phase-noise spiral-LC CMOS VCO

Abstract: A completely integrated 1.8-GHz low-phase-noise voltage-controlled oscillator is presented. The design relies heavily on the integrated spiral inductors, which are constructed with only two metal layers and without etching. The effects of eddy currents and losses in the heavily doped substrate have been simulated and modeled with finite-element analyses. The achieved phase noise is as low as -116 dBc/Hz at 600 kHz offset, at a power consumption of only 6 mW. The VCO's tuning range is 250 MHz.

Time domain analysis and its practical application to the measurement of phase noise and jitter

Abstract: The precise determination of phase is necessary for a very large set of measurements. Traditionally, phase measurements have been made using analog phase detectors which suffer from limited accuracy and dynamic range. This paper describes how phase digitizing, which uses time domain techniques, removes these limitations. Phase digitizing is accomplished using a time interval analyzer, which measures the signal zero-crossing times. These zero-crossing times are processed to compute phase deviation, with the reference frequency specified as a numerical value or derived from the times themselves. Phase digitizing can be applied even in the presence of modulation, as the underlying clock can be reconstructed in software to fit the data. Measurements derived from this phase data such as phase noise, jitter analysis, Allan variance (AVAR), maximum time interval error (MTIE), and time deviation (TDEV) are applied to such applications as the characterization of oscillators, computer clocks, chirp radar, token ring networks, and tributaries in communication systems.

Locking characteristics of a passively mode-locked monolithic DBR laser stabilized by optical injection

Abstract: We demonstrate the generation of ultrastable millimeter-wave carriers from a passively mode-locked monolithic InGaAs MQW DBR laser injection locked by a double sideband suppressed carrier modulated optical signal. We investigate the effect of the optical power and the wavelength of the injection signal on the phase noise of the generated millimeter-wave carrier. Once locked, the laser can track the variations in the beat frequency of the injected millimeter-wave signal over an RF frequency range of approximately 172 MHz.

Carrier tracking technique and apparatus having automatic flywheel/tracking/reacquisition control and extended signal to noise ratio

Abstract: The carrier tracking loop technique and apparatus provides smooth, accurate frequency tracking, fast reacquisition and doppler tracking over a wide dynamic range. The loop parameters of the carrier tracking loop are varied as a function of mode, i.e. flywheel, tracking or reacquisition modes. The various modes of operation are automatically detected and loop operation is enhanced by non-linear techniques. The enhancements include fourth power sample normalization to improve performance over a large dynamic range and to ease fixed point scaling. A slope limiter is included which aids in coherent detection by reducing phase noise introduced by the carrier tracking loop. Also, a predifferentiation filter further aids in coherent detection by reducing phase noise.