{"title":"Direct Digital Simultaneous Phase-Amplitude Noise and Allan Deviation Measurement System","authors":"Marco Pomponio;Archita Hati;Craig Nelson","doi":"10.1109/OJUFFC.2024.3487147","DOIUrl":null,"url":null,"abstract":"In this paper, we present a direct digital measurement system capable of simultaneously measuring phase noise, amplitude noise, and Allan deviation with and without cross-correlation. The residual phase noise of the single-channel system achieves \n<inline-formula> <tex-math>$\\mathscr {L}\\left ({{1 \\text {Hz}}}\\right)~ \\textrm {=} -143 \\text {dBc/Hz}$ </tex-math></inline-formula>\n for a 10 MHz input signal and an Allan deviation noise floor of \n<inline-formula> <tex-math>$3.2 \\times 10^{-15}$ </tex-math></inline-formula>\n at 1 second averaging time (\n<inline-formula> <tex-math>$\\tau $ </tex-math></inline-formula>\n). The system’s performance improves as expected with cross-correlation, resulting in an average-limited residual white noise floor of −185 dBc/Hz after only a few minutes of averaging, an improvement of 30 dB compared to a single-channel system. It also reaches an average limited flicker phase noise floor of \n<inline-formula> <tex-math>$\\mathscr {L}\\left ({{1 \\text {Hz}}}\\right) ~\\textrm {=} -160 \\text {dBc/Hz}$ </tex-math></inline-formula>\n within two days, with an Allan deviation of \n<inline-formula> <tex-math>$5 \\times 10^{-16}$ </tex-math></inline-formula>\n @ \n<inline-formula> <tex-math>$\\tau ~\\textrm {=}1 \\text {second}$ </tex-math></inline-formula>\n. To our knowledge, this represents the lowest noise performance ever reported for a digital measurement system. Our solution is based on a pair of high-performance analog-to-digital converters and a single system-on-a-chip (SoC) with multiple processors and a field programmable gate array (FPGA). The architecture allows for processing all data samples in real-time without dead-time between calculation frames, enabling the fastest averaging possible during cross-correlation.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"4 ","pages":"160-170"},"PeriodicalIF":0.0000,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10737107","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","FirstCategoryId":"1085","ListUrlMain":"https://ieeexplore.ieee.org/document/10737107/","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper, we present a direct digital measurement system capable of simultaneously measuring phase noise, amplitude noise, and Allan deviation with and without cross-correlation. The residual phase noise of the single-channel system achieves
$\mathscr {L}\left ({{1 \text {Hz}}}\right)~ \textrm {=} -143 \text {dBc/Hz}$
for a 10 MHz input signal and an Allan deviation noise floor of
$3.2 \times 10^{-15}$
at 1 second averaging time (
$\tau $
). The system’s performance improves as expected with cross-correlation, resulting in an average-limited residual white noise floor of −185 dBc/Hz after only a few minutes of averaging, an improvement of 30 dB compared to a single-channel system. It also reaches an average limited flicker phase noise floor of
$\mathscr {L}\left ({{1 \text {Hz}}}\right) ~\textrm {=} -160 \text {dBc/Hz}$
within two days, with an Allan deviation of
$5 \times 10^{-16}$
@
$\tau ~\textrm {=}1 \text {second}$
. To our knowledge, this represents the lowest noise performance ever reported for a digital measurement system. Our solution is based on a pair of high-performance analog-to-digital converters and a single system-on-a-chip (SoC) with multiple processors and a field programmable gate array (FPGA). The architecture allows for processing all data samples in real-time without dead-time between calculation frames, enabling the fastest averaging possible during cross-correlation.