Donnelly Christine A, Brevik Justus A, Dresselhaus Paul D, Hopkins Peter F, Benz Samuel P
Superconductive Electronics Group, National Institute of Standards and Technology (NIST), Boulder, CO 80305 USA.
Department of Electrical Engineering, Stanford University, Stanford, CA 94305 USA.
IEEE Trans Microw Theory Tech. 2018 Nov;66(11). doi: 10.1109/tmtt.2018.2856775.
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.
我们展示了对具有基本精确输出脉冲的超导电压基准波形合成器的首次抖动灵敏度分析。在微波频率成功部署基准波形源将代表射频计量的一种新范式。本文所考虑的可编程波形合成器包含一个采样频率为28 GHz的1.5位增量 - 西格玛数模转换器（DAC）。我们量化了随机和确定性输出脉冲位置抖动（PPJ）对以下两方面的影响：1）输出基波的幅度精度，以及2）带内信噪失真比（SNDR）。该超导DAC完全没有输出脉冲宽度抖动，并且对于高达1 GHz的合成音调，高达200 fs rms的随机PPJ对精度和SNDR的影响可忽略不计。然而，施加非零直流偏置电流会产生高达5 ps的确定性PPJ，反过来，这会导致在1 GHz时带内SNDR下降30 dB，除非采用本文讨论的技术消除。我们通过在100 kHz - 1 GHz范围内的模拟以及在100 kHz - 3 MHz范围内的实验验证了随机和确定性PPJ的预测效果。
