Effect Of Phase Jitter Research Articles

Examination of optimized ultrashort three-color waveforms for generating short and intense isolated attosecond pulses in soft x rays

Isolated attosecond pulses (IAPs) can be readily generated via high-order harmonic generation driven by an ultrashort laser pulse. Here, it is shown that the best way to obtain the ultrashort waveform for producing a short and intense IAP in the soft x rays is to optimize the three-color (TC) laser pulse consisting of the fundamental field and its second and third harmonic fields. To calibrate it, another way of constructing the ultrashort waveform directly in time using a truncated basis set of B-spline functions is first proposed. The calibration waveform (CW) contains more frequency components up to the eighth harmonic order. It is found that the IAP by the TC waveform has a shorter duration after macroscopic propagation in a nonlinear gas medium compared to that by the CW field. It is uncovered that the CW field is additionally modified by the higher-order frequency components during propagation, dominated by the neutral atom dispersion. The effect of phase jitter in the TC waveform and the extension of the TC scheme into higher photon energies are also discussed. Currently, precise control of TC laser waveform synthesis is already achievable in the labs, thus paving an effective way for generating a useful attosecond light source in the soft x rays.

Simulation Analysis of Phase Jitter in Differential Sampling of AC Waveforms Based on the Programmable Josephson Voltage Standard

The effect of phase jitter on differential sampling using the programmable Josephson voltage standard (PJVS) system is studied in this paper. A phase jitter model is established for the measured signal, and compensation coefficients for phase jitter removal are derived for three different post-processing methods based on the discrete Fourier transform algorithm (DFT). Based on our analysis, the phase jitter compensation coefficients are determined by the phase jitter angle distribution and harmonic order. Furthermore, after analyzing and simulating various common distributions, the phase jitter compensation coefficients have been verified. The simulation shows that when the standard deviation of the phase jitter angle is 20 ns, and the frequency of the measuring waveform is 3.46 kHz, the influence of the phase jitter is 1 × 10−7. The results of the simulation indicate that, in the differential sampling of AC waveforms using a PJVS system, phase jitter is one of the error terms for an uncertainty budget that cannot be neglected, particularly as the frequency of the measured waveforms increases.

Effects of Phase Jitter on the Navigation Signal Simulator

As the measuring equipment of the navigation receivers, high precision pseudorange signal is generated by navigation signal simulator. Pseudorange error is mainly from modeling error in high dynamic scenarios, but it is mainly from phase quantization error of digital implementation process in high precision scenarios of evaluating receiver’s pseudorange accuracy. Is this paper, according to the implementation principle of carrier and code DDS, the causes of the phase quantization error is analyzed and the pseudorange error formula is derived and the simulation results are given. Analysis and simulation results show that phase critter originated by carry phase truncation effects measurement result of zero value and cannot be ignored. The conclusion can guide the design of navigation signal simulator.

Superintense laser fields in circular array: effects of phase and pulse jitters

Extremely intense laser field that makes nonlinear quantum vacuum can be generated by coherent superposition of multiple lasers in circular configuration that incorporates optical fibers synchronization scheme and piecewise mirrors in circular array operating below typical damage threshold. Coherent amplification and large laser beams can produce intensity reaching nonlinear quantum vacuum regime. The effects of phase jitter and envelope timing of the pulses due to imperfect synchronization are simulated and analyzed for both linear and circularly polarized pulses. We obtain simple analytical expressions that well describe the envelope jitter and phase jitter. Several practical aspects are discussed, including implications of scaling the laser dimension and pulse duration, with possibility for giant laser facility.

Collaborative beamforming for distributed wireless ad hoc sensor networks

The performance of collaborative beamforming is analyzed using the theory of random arrays. The statistical average and distribution of the beampattern of randomly generated phased arrays is derived in the framework of wireless ad hoc sensor networks. Each sensor node is assumed to have a single isotropic antenna and nodes in the cluster collaboratively transmit the signal such that the signal in the target direction is coherently added in the far- eld region. It is shown that with N sensor nodes uniformly distributed over a disk, the directivity can approach N, provided that the nodes are located sparsely enough. The distribution of the maximum sidelobe peak is also studied. With the application to ad hoc networks in mind, two scenarios, closed-loop and open-loop, are considered. Associated with these scenarios, the effects of phase jitter and location estimation errors on the average beampattern are also analyzed.

160 Gbit∕s wavelength converter with 3R-regenerating capability

A 160 Gbit/s all-optical wavelength converter with 3R-regenerating capability is demonstrated. The 3R-wavelength converter uses an optical decision gate based on ultrafast fibre nonlinearity to switch a 160 GHz pulse train by the incoming 160 Gbit/s data signal. A pulse shaper is implemented to reduce the detrimental effect of phase jitter in the decision gate and a fibre-based wavelength shifter for free allocation of the wavelength at the output.

On the effects of phase jitter on QPSK lock detection

The performance of a QPSK (quadrature phase-shift keying) lock detector is described, taking into account the degradation due to carrier phase jitter. Such an analysis is necessary for accurate performance prediction purposes in scenarios where both the loop SNR is low and the estimation period is short. The derived formulas are applicable to several QPSK loops and are verified using computer simulations.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Adjacent-Channel and Quadrature-Channel Interference in Minimum Shift Keying

In this paper we present formulas for the computation of error probability in the presence of quadrature-channel or adjacentchannel interference in addition to intersymbol interference in a minimum shift keying system. The filters in the receiver and transmitter are arbitrary but with a finite number of poles. The effect of phase jitter in the main channel, phase and symbol timing misalignment in the interfering channels, and sampling time jitter is taken into account. The probability of error is averaged over the phase and symbol timing misalignment. Numerical results are presented for Butterworth filters in the receiver and transmitter with two, three, and four poles. Curves of error probability as a function of various variables (signal-to-noise ratio, bandwidth of receiver and transmitter filters, number of poles, channel frequency separation, phase jitter, sampling time, and symbol timing and phase misalignment) are presented. The method of this paper can readily be applied to other filters; hence, it can be used in the design and prediction of the performance of digital communication systems.

Effects of Jitter and Cycle Slipping of Phase Reference Upon Unique Word Missed Detection in QPSK Systems

The effects of phase jitter and cycle slipping of the recovered carrier upon unique word (UW) missed detection in QPSK systems are investigated. Schrempp et al. have already presented the relationship between the UW missed detection probability (UWMP) and the bit error probability, which is simple and useful as long as the phase reference is noiseless. However, when the authors recently made some theoretical and experimental assessments of UW missed detection, they found that the above disturbances of the recovered carrier significantly affected the UW missed detection performance. Specifically, the actual UWMP was often worse than that predicted hy Schrempp et al. In fact, a bottoming effect takes place in the UWMP versus UW length characteristic. In this paper, after obtaining the conditional symbol and bit error probabilities for the recovered carrier with some phase error, we discuss the nature of phase fluctuation and cycle slipping for the recovered carrier. Consequently, we derive general expressions for the UWMP in both CPSK and DCPSK transmissions. The UWMP's are numerically calculated, and are then compared to our experimental data.

Application of Gauss Quadrature Rules to Digital Communication Problems

In multilevel bandpass data transmission there is usually a difference between the phase of the carrier signal and the phase of the receiver oscillator, thereby causing imperfect demodulation. The use of nonclassical Gauss quadrature rules (GQR's) allows: 1) a theoretical study of the joint effects of phase jitter, thermal noise, and intersymbol interference on average error probability; and 2) a maximum-precision sampling technique in the simulation of digital communication systems. On this basis, the mean-square-error and zero-forcing equalizers are considered, and their performances evaluated in terms of the average error probability for multilevel pulse-amplitude-modulation (PAM) and partial-response-coded (PRC) signaling schemes.

The Effect of Phase Jitter on the Performance of a First-Order Phase-Locked Loop

A filterless phase-locked loop is considered with an arbitrary periodic phase comparator. The loop has a jittered input and is perturbed by thermal noise. Under such conditions the loop skips cycles from time to time. A study is made of the statistical behavior of the loop and emphasis is placed on the determination of the average time of skipping cycles. This problem is related to the first passage time problem of mathematical statistics and has been studied by a number of authors [1], [2], [3], [15]. The specific interest in the present paper is the study of the effect of timing jitter on the "spilling" of stores in a digital transmission system. A comparison of the average frequency of "spilling' the stores is made for a sawtooth, sinusoidal, and an "inscribed in" and "circumscribed about" triangular phase comparator. Examples using numbers typical of a digital transmission system show that the average frequency of "spilling" the stores in the time division multiplex should be exceedingly small.