Pulse Width Jitter Research Articles

Jitter Suppression Techniques for High-Speed Sample-and-Hold Circuits

In this paper, we discuss the limitations of the existing clock jitter reduction techniques, and introduce $\Delta \Sigma $ sampling, which can reduce the jitter-induced sampling error significantly. We investigate various feedback configurations, and show that NRZ and RZ feedback techniques both improve the jitter shaping properties of the $\Delta \Sigma $ sampler. However, in order to benefit from the superior jitter shaping, a constant feedback pulsewidth is required. We propose a new clocking scheme, called correlated clocking to address the feedback pulsewidth variations. This technique utilizes the correlation between the rising and falling edges of the on-chip clocks to eliminate the feedback pulsewidth jitter. We show that a $1^{st}$ -order $\Delta \Sigma $ sampler with correlated RZ feedback can achieve the same SJNR as a $\Delta \Sigma $ sampler with switched-capacitor feedback. We then expand our analysis to $2^{nd}$ - and higher-order modulators, and show that contrary to common belief, even with constant-pulsewidth feedback, higher-order modulators are limited by the feedback pulse jitter. We conclude that the maximum benefit of a $\Delta \Sigma $ sampler with a conventional single-loop architecture is independent of the loop order, feedback mechanism, and the oversampling ratio, and it reaches 4.77 dB for OSR≥5.

Jitter Sensitivity Analysis of the Superconducting Josephson Arbitrary Waveform Synthesizer.

We present the first jitter sensitivity analysis of a superconducting voltage reference waveform synthesizer with fundamentally accurate output pulses. Successful deployment of a reference waveform source at microwave frequencies will represent a new paradigm for radio frequency metrology. The programmable waveform synthesizer considered in this paper contains a 1.5 bit delta-sigma digital-to-analog converter (DAC) with a sampling frequency of 28 GHz. We quantify the impact of random and deterministic output pulse position jitter (PPJ) on: 1) the amplitude accuracy of the output fundamental tone and 2) the in-band signal-to-noise and distortion ratio (SNDR). The superconducting DAC features a complete lack of output pulsewidth jitter, and random PPJ up to 200 fs rms has a negligible impact on accuracy and SNDR for synthesized tones up to 1 GHz. However, application of nonzero dc bias current is shown to produce deterministic PPJ of up to 5 ps, which, in turn, is shown to degrade the in-band SNDR by 30 dB at 1 GHz unless eliminated with techniques discussed in this paper. We verify the predicted effects of random and deterministic PPJ with simulations in the range of 100 kHz-1 GHz and with experiments in the range of 100 kHz-3 MHz.

A Current Consumption Measurement Approach for FPGA-Based Embedded Systems

In this paper, an approach for the current-consumption measurement of a field-programmable gate array (FPGA)-based embedded system is presented. This approach is based on the current conversion to pulsewidth using the external-to-FPGA capacitor charging circuit and comparator. The pulsewidth is then measured using the timer synthesized inside the FPGA. Measurement uncertainty budget analysis is performed. It reveals the parameters mostly affecting steady-state current measurement uncertainty. Sources contributing to the budget of current measurement uncertainty include directly measured pulsewidth, manufacturing scattering of measurement setup component parameters, and their fluctuations in response to the measured current value. A calibration procedure enabling to reduce the influence of charging circuit component manufacturing tolerances on measurement uncertainty is suggested. The current measurement prototype is developed and tested. Measured pulsewidth jitter is estimated experimentally using the prototype. The jitter influence on measurement uncertainty is modeled by including the corresponding quantity in the measurement model. The influence of the temperature on measurement uncertainty is estimated using Monte Carlo simulation.

Characterization of the Excess Noise Conversion From Optical Relative Intensity Noise in the Photodetection of Mode-Locked Lasers for Microwave Signal Synthesis

Excess noise converted from the optical relative intensity noise (RIN) has limited the noise performance in the microwave signal synthesis application for mode-locked lasers. In this paper, a method for detailed characterization of the excess noise conversion from the optical RIN to the electrical pulse width jitter (PWJ), electrical relative amplitude noise (RAN) and electrical phase noise in the photodetection of mode-locked lasers is proposed. With the measured noise conversion ratios, one can predict the electrical RAN and phase noise power spectral densities under different input optical powers. The effect of the pulse width and peak power of the incident optical pulses and the effect of the saturation power of the photodetectors are also investigated. The results are used to suggest guidelines for achieving low-noise photodetection for microwave signal synthesis application.

Feedforward spectral shaping technique for clock-jitter induced errors in digital-to-analogue converters

A simple feedforward spectral shaping technique for the pulsewidth jitter induced errors in digital-to-analogue converters (DACs) is presented. The proposed technique features a feedforward combination of the conventional rectangular-pulse switched-current DAC and a discrete-time switched-capacitor DAC to achieve spectral shaping for the jitter induced error. The benefit of this hybrid DAC solution using error specral shaping is illustrated in the context of feedback DACs used in continuous-time ΔΣ modulators. Simulation results show that the jitter tolerance of the proposed DAC solution is equivalent to that of the commonly used jitter-tolerant exponentially-decaying waveform switched-capacitor-resistor DAC structure, but at much more relaxed slew-rate requirement on the op-amp used in the DAC load circuit, which translates into significant power savings.

基于雪崩管Marx电路的高稳定度脉冲技术

The merits of the full-solid-state pulser, based on avalanche transistor, are high stability, narrow pulse and short rise-time. But the disadvantage of this pulser is that its output power is low, thus Marx circuit is used to improve the peak-voltage. In this paper, the effect factors of the time-stability and shape-stability are analyzed, some optimizing measures are used to improve the stability, and a high-stability pulser is designed. The pulser’s peak voltage is 2 000 V, pulse width is 5 ns, repetition frequency is higher than 25 kHz, and the pulse width jitter is less than 1% and the peak voltage jitter is less than 1%.

Design and Measurement of a CT $\Delta\Sigma$ ADC With Switched-Capacitor Switched-Resistor Feedback

The performance of traditional continuous-time (CT) delta-sigma (DeltaSigma) analog-to-digital converters (ADCs) is limited by their large sensitivity to feedback pulse-width variations caused by clock jitter in their feedback digital-to-analog converters (DACs). To mitigate that effect, we propose a modified switched-capacitor (SC) feedback DAC technique, with a variable switched series resistor (SR). The architecture has the additional benefit of reducing the typically high SC DAC output peak currents, resulting in reduced slew-rate requirements for the loop-filter integrators. A theoretical investigation is carried out which provides new insight into the synthesis of switched-capacitor with switched series resistor (SCSR) DACs with a specified reduction of the pulse-width jitter sensitivity and minimal power consumption and complexity. To demonstrate the concept and to verify the reduced pulse-width jitter sensitivity a 5 mW, 312 MHz, second order, low-pass, 1-bit, CT DeltaSigma modulator with SCSR feedback was implemented in a 1.2 V, 90 nm, RF-CMOS process. An SNR of 66.4 dB and an SNDR of 62.4 dB were measured in a 1.92 MHz bandwidth. The sensitivity to wideband clock phase noise was reduced by 30 dB compared to a traditional switched-current (SI) return-to-zero (RZ) DAC.

Pulse-Width Jitter Measurement for Laser Diode Pulses

Theoretical analysis and experimental measurement of pulse-width jitterof diode laser pulses are presented. The expression of pulse powerspectra with all amplitude jitter, timing jitter and pulse-width jitteris deduced. The power spectra with and without pulse-width jitter arenumerically simulated. The simulation results indicate that thepulse-width jitter will contribute considerably noise to the pulse powerspectrum while the product of pulse width and angular frequency islarger than 1. The experimental measurement of pulse-width jitter ofa gain-switched Fabry–Perot laser diode with 2.4 GHz repetition rate isalso reported. In comparison of the noise power spectra of the first,fourth and seventh harmonics of the pulse repetition rate, 2.3 pspulse-width jitter is obtained.

Spectral technique for measuring the pulse-width jitter of a gain-switched laser

We report the experimental investigation of the harmonic number dependence of the noise power spectrum of a train of Gaussian pulses from a gain-switched semiconductor laser. In particular, we examined the dependence under the condition of τω>1, where τ is the pulse-width and ω is the angular frequency. We demonstrated that: (a) the spectral noise function is fully described by a fourth order polynomial, (b) the pulse-width jitter is 5 ps, and (c) there is significant correlation between the different types of jitter (amplitude, timing, and width).

Measurement of pulse width and amplitude jitter noises of gigahertz optical pulse trains by time-domain demodulation

We propose a technique for measuring both pulse width and amplitude jitter noises of high-repetition-rate optical pulse trains and the cross correlation between these noises as well. The technique is based on time-domain amplitude demodulation of three harmonic components of the detected pulse train. We applied this technique to characterize noises of a gigahertz optical pulse train generated by an actively mode-locked Er-doped fiber laser. Correlation between pulse width jitter and pulse amplitude jitter was observed at low frequencies in this laser. Unlike relaxation oscillation noise, low-frequency noise is free from pulse energy jitter. Owing to its ability to measure pulse width jitter in addition to amplitude and phase jitters, this technique is of great interest for characterizing noises of a wide variety of optical pulse train sources.

Analysis of and detector comparisons using the microtrack model of magnetic recording

We rely on accurate and relatively simple models of the magnetic recording process so that signal processing algorithms that operate with different system parameters can be compared fairly. The microtrack model of thin-film recording, posed by researchers to mimic the random, zig-zag transition boundaries, satisfies our requirements for an accurate and simple model. This paper summarizes analysis of the microtrack model done by Caroselli and Wolf (1995, 96) and presents additional results including simulations of detectors. Parallels are drawn between the microtrack model and other models including a stationary additive noise model, a model of partial erasure, and a model of transition jitter, amplitude reduction, and pulse width jitter. The parameters used by the microtrack model can be derived from physical media; we derive parameters for these other models from those of the microtrack model.

A single-pulse trigger generator for a 10 MeV electron linear accelerator

A new trigger generator has been designed in order to make the Varian V-7700 accelerator suited for pulsed radiolysis experiments. Provisions have been made to obtain single electron pulses with small variations in pulse dose. The obtained electron pulse width is continuously adjustable from 0.25–4 μsec, the pulse width jitter is max. 20 nsec. Variation in the average electron energy from pulse to pulse is reduced to 1%. For a 1 μsec electron pulse, the typical pulse width used for pulsed radiolysis, the dose variation from pulse to pulse will not excess more than 3%.