Skip to content

W
White Rabbit
Commit 2d9ecce5 authored by Maciej Lipinski's avatar Maciej Lipinski
Browse files
Options

[WIP] first full version

parent 68a86b64
Hide whitespace changes
Inline Side-by-side
Showing with 433 additions and 245 deletions
presentations/WR_Maciej_EFTS_2019/wr_efts_2019.tex
View file @ 2d9ecce5
...@@ -98,7 +98,7 @@ ...@@ -98,7 +98,7 @@
\subsection{} \subsection{}
%======================= %=======================
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{What is White Rabbit?} \begin{frame}{What is White Rabbit [1]?}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{columns}[c] \begin{columns}[c]
\column{0.75\textwidth} \column{0.75\textwidth}
...@@ -144,7 +144,7 @@ ...@@ -144,7 +144,7 @@
\includegraphics[width=1.0\textwidth]{misc/WR-zoo.jpg}\vspace{-1cm} \includegraphics[width=1.0\textwidth]{misc/WR-zoo.jpg}\vspace{-1cm}
\begin{center} \begin{center}
\small \small
\textbf{Companies selling White Rabbit:} \url{www.ohwr.org/projects/white-rabbit/wiki/wrcompanies} \textbf{Companies selling White Rabbit [2]:} \url{www.ohwr.org/projects/white-rabbit/wiki/wrcompanies}
\end{center} \end{center}
\end{frame} \end{frame}
...@@ -198,8 +198,8 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -198,8 +198,8 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
\end{columns} \end{columns}
\pause\pause\pause\pause\pause \pause\pause\pause\pause\pause
{\scriptsize Users page: \url{http://www.ohwr.org/projects/white-rabbit/wiki/WRUsers}} {\scriptsize See user page [3]: \url{http://www.ohwr.org/projects/white-rabbit/wiki/WRUsers}}
{\scriptsize Article:\textit{White Rabbit Applications and Enhancements}, M.Lipinski et. al, ISPCS2018} {\scriptsize See also article [4] and newsletter [5]}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
...@@ -236,8 +236,8 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -236,8 +236,8 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
\item Frame-based synchronisation protocol \item Frame-based synchronisation protocol
\item Simple calculations: \item Simple calculations:
\begin{itemize} \begin{itemize}
\item link $delay_{ms}$ $\delta_{ms} = \frac{(t_{4}-t_{1}) - (t_{3}-t_{2})}{2}$ \item link delay: $\delta_{ms} = \frac{(t_{4}-t_{1}) - (t_{3}-t_{2})}{2}$
\item clock $offset_{ms} = t_{2} - (t_{1} + \delta_{ms})$ \item offset from master: $OFM = t_{2} - (t_{1} + \delta_{ms})$
\end{itemize} \end{itemize}
\item<2-> Hierarchical network \item<2-> Hierarchical network
\item<3-> Disadvantages \item<3-> Disadvantages
...@@ -295,20 +295,27 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -295,20 +295,27 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
\column{.65\textwidth} \column{.65\textwidth}
\footnotesize \footnotesize
\begin{itemize} \begin{itemize}
\item <1->Previous tricks allow high precision of round trip measurement \item <1->Previous tricks allow high precision of round trip (RTT) measurement: $RTT=(t_{4}-t_{1}) - (t_{3}-t_{2})$
\item <2->Accurate synchronization requires mitigation of link asymmetries \item <2->Accuracy requires mitigation of asymmetries
\item <3->Sources of asymmetry: FPGA, PCB, SFP electrics/optics, wavelenght (1, chromatic dispertion \item <3->Asymmetry sources: FPGA, PCB, SFP electrics/optics, chromatic dispersion [6,7]
\item <4->Link delay model \item <4->Link delay model:
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item \textbf{Fixed delays:} assumed constant, calibrated/measured \item \textbf{Fixed delays:} assumed constant, calibrated/measured
\item \textbf{Variable delays:} online evaluation with fiber asymmetry coefficient: $\alpha = \frac{\nu_g(\lambda_s)}{\nu_g(\lambda_s)} -1 = \frac{\delta_{MS} - \delta_{SM}}{\delta_{SM}}$ \item \textbf{Variable delays:} online evaluation with fiber asymmetry coefficient: $\alpha = \frac{\nu_g(\lambda_s)}{\nu_g(\lambda_s)} -1 = \frac{\delta_{MS} - \delta_{SM}}{\delta_{SM}}$
\end{itemize} \end{itemize}
\item <5-> Correcting offset from master (OFM):\scriptsize \\
% $RTT=(t_{4}-t_{1}) - (t_{3}-t_{2})$\\
$\delta_{ms}~ = \frac{1 + \alpha}{2 + \alpha} \, (RTT - \Delta - \epsilon)$
$OFM = t_{2} - (t_{1} + \delta_{ms} + \Delta_{txm} + \Delta_{rxs} + \epsilon_S)$
\end{itemize} \end{itemize}
\column{.5\textwidth} \column{.5\textwidth}
\includegraphics[width=1.0\textwidth]{protocol/link-delay-model-detailed.jpg} \begin{center}
\includegraphics[width=1.0\textwidth]{protocol/link-delay-model-detailed.jpg}\\
\tiny See: \textit{WR Calibration} [8]
\end{center}
\end{columns} \end{columns}
\pause\pause\pause\pause % \pause\pause\pause\pause
\scriptsize See: \textit{WR Calibration}, version 1.1, G.Daniluk % \scriptsize See: \textit{WR Calibration}, version 1.1, G.Daniluk
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
...@@ -321,7 +328,7 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -321,7 +328,7 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
\end{center} \end{center}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[t,fragile]{White Rabbit Switch} \begin{frame}[t,fragile]{White Rabbit Switch [9]}
\begin{center} \begin{center}
\includegraphics[width=\textwidth]{switch/wrSwitch_v3_3.jpg} \includegraphics[width=\textwidth]{switch/wrSwitch_v3_3.jpg}
\begin{itemize}\small \begin{itemize}\small
...@@ -346,7 +353,7 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -346,7 +353,7 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{WR Node: carrier board + FMC} \begin{frame}{WR Node [10]: carrier board + FMC}
\vspace{-0.5cm} \vspace{-0.5cm}
\begin{center} \begin{center}
\includegraphics[width=10cm]{node/shw_kit2.png} \includegraphics[width=10cm]{node/shw_kit2.png}
...@@ -369,92 +376,125 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -369,92 +376,125 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
\end{columns} \end{columns}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{White Rabbit PTP Core} \begin{frame}{White Rabbit PTP Core [11]}
\begin{center} \begin{center}
\includegraphics[width=\textheight]{node/wrNode.jpg} \includegraphics[width=\textheight]{node/wrNode.jpg}
\end{center} \end{center}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Performance} \section{Performance}
\subsection{} \subsection{Current}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{frame}{WR time transfer performance: basic test setup}
\begin{center}
\includegraphics[height=7.0cm]{measurements/meas_setup.pdf}
\end{center}
\end{frame}
\begin{frame}{WR time transfer performance: test results}
\begin{center}
\includegraphics[height=6.0cm]{measurements/meas_results2.pdf}\\
Reported in 2011 in [4]
\end{center}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Improvements}
\begin{frame}{Performance limits and improvements}
\begin{center}
\includegraphics<1>[width=\textwidth]{misc/inaccuracy-sources.jpg}
\includegraphics<2>[width=\textwidth]{misc/inaccuracy-sources-fixed-delays.jpg}
\end{center}
\end{frame}
\begin{frame}{Hardware asymmetry compensation} \begin{frame}{Hardware asymmetry compensation}
\begin{center}\vspace{-0.3cm} % \begin{center}\vspace{-0.3cm}
\includegraphics<1-2>[height=2.3cm]{misc/inaccuracy-sources-fixed-delays.jpg} % \includegraphics<1-2>[height=2.3cm]{misc/inaccuracy-sources-fixed-delays.jpg}
\includegraphics<3>[height=2.3cm]{protocol/bitslide.jpg} % \includegraphics<3>[height=2.3cm]{protocol/bitslide.jpg}
\includegraphics<4->[height=2.3cm]{misc/inaccuracy-sources-fixed-delays.jpg} % \includegraphics<4->[height=2.3cm]{misc/inaccuracy-sources-fixed-delays.jpg}
\end{center} % \end{center}
\begin{columns}[c] \begin{columns}[c]
\column{0.81\textwidth}\vspace{-0.5cm} \column{0.6\textwidth}\vspace{-0.5cm}
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item<2-> \textbf{Bitslide} -- measurement uncertainty \item<1-> \textbf{Bitslide} -- measurement uncertainty
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item Measured each time link goes up \item Measured each time link goes up
\item Value provided by GTX of FPGA \item Value provided by GTX of FPGA
\item Error: $\pm$25ps [2] \item Error: $\pm$25ps [7]
\item Remedy: ensure bitslide is zero \\(ongoing work at CERN) \item Remedy: ensure bitslide is zero \\(ongoing work at CERN)
\end{itemize} \end{itemize}
\item<5-> \textbf{PCB, FPGA, SFP} -- hardware delay uncertainty \item<2-> \textbf{PCB, FPGA, SFP} -- hardware delay uncertainty
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item Calibration uncertiainty: sdev of 2ps [2] \item Calibration uncertiainty: sdev of 2ps [7]
\item Linear dependency on temp (700ps over $-10..55^oC$): \item Linear dependency on temp (700ps over $-10..55^oC$):
\begin{itemize}\tiny \begin{itemize}\tiny
\item CuteWR: tx $-8.4ps/K$, rx $13.3ps/K$ [1] \item CuteWR: tx $-8.4ps/K$, rx $13.3ps/K$ [6]
\item Switch: 8ps/K [2] \item Switch: 8ps/K [7]
\item WR-Zen: 4ps/K [2] \item WR-Zen: 4ps/K [7]
\end{itemize} \end{itemize}
\item Remedy: active compensation \\(implemented for LHASSO, 50ps over $-10..55^oC$ [1]) \item Remedy: active compensation \\(implemented for LHASSO, 50ps over $-10..55^oC$ [6])
% \item SFP delay dependency on input power, error up to 30ps [2] % \item SFP delay dependency on input power, error up to 30ps [2]
\end{itemize} \end{itemize}
\end{itemize} \end{itemize}
\column{0.38\textwidth} \column{0.5\textwidth}
\begin{center} \begin{center}
\includegraphics<6>[width=\textwidth]{measurements/fixed-delays-temp-dependency.jpg} \includegraphics<1>[width=\textwidth]{protocol/bitslide.jpg}
\tiny\pause\pause\pause\pause\pause \includegraphics<2>[width=\textwidth]{measurements/fixed-delays-temp-dependency.jpg}\\
Figure Figure source: [1] \tiny\pause
Figure source: [6]
\end{center} \end{center}
\end{columns} \end{columns}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Performance limits and improvements}
\begin{center}
\includegraphics[width=\textwidth]{misc/inaccuracy-sources-variable-delays.jpg}
\end{center}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Medium asymmetry compensation} \begin{frame}{Medium asymmetry compensation}
\begin{center}\vspace{-0.3cm} % \begin{center}\vspace{-0.3cm}
\includegraphics[height=2.3cm]{misc/inaccuracy-sources-variable-delays.jpg} % \includegraphics[height=2.3cm]{misc/inaccuracy-sources-variable-delays.jpg}
\end{center} % \end{center}
\begin{columns}[c] \begin{columns}[c]
\column{0.7\textwidth}\vspace{-0.5cm} \column{0.7\textwidth}\vspace{-0.5cm}
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item<2-> \textbf{SFP} -- tx wavelength uncertainty \item<1-> \textbf{SFP} -- tx wavelength uncertainty
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item<3-> Allowed departure from nominal value \\(10nm at 1490nm, 50nm at 1310nm [2]) \item<2-> Allowed departure from nominal value \\(10nm at 1490nm, 50nm at 1310nm [7])
\item<4-> Linear dependency on SFP temp: \item<3-> Linear dependency on SFP temp:
\begin{itemize}\tiny \begin{itemize}\tiny
\item SFP@1310nm: $0.11 ps/(K \cdot km)$ [1] \item SFP@1310nm: $0.11 ps/(K \cdot km)$ [6]
\item SFP@1490nm: $-0.51 ps/(K \cdot km)$ [1] \item SFP@1490nm: $-0.51 ps/(K \cdot km)$ [6]
\item SFP@1550nm: $1.7ps/(K \cdot km)$ [2] \item SFP@1550nm: $1.7ps/(K \cdot km)$ [7]
\end{itemize} \end{itemize}
\end{itemize} \end{itemize}
\item<5-> \textbf{Fiber} -- chromatic dispersion variation \item<4-> \textbf{Fiber} -- chromatic dispersion variation
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item Linear dependency on fiber temp: \item Linear dependency on fiber temp:
\begin{itemize}\tiny \begin{itemize}\tiny
\item G652.D at 1310/1490: $-0.2 ps/(K\cdot km)$ [1] \item G652.D at 1310/1490: $-0.2 ps/(K\cdot km)$ [6]
\item G652.D at 1310/1490: $-0.12 ps/(K\cdot km)$ [2] \item G652.D at 1310/1490: $-0.12 ps/(K\cdot km)$ [7]
\item G652.D at 1490/1550: $-0.05 ps/(K\cdot km)$ [2] \item G652.D at 1490/1550: $-0.05 ps/(K\cdot km)$ [7]
\end{itemize} \end{itemize}
\end{itemize} \end{itemize}
\item<6-> Significant for links $>10km$ \item<5-> Significant for links $>10km$
\item<7-> Remedy: temp-stabilized SFP, closer wavelength \\(CH21\& CH23 @ 1560.61 \& 1558.98 in SKA [1]) \item<6-> Remedy: temp-stabilized SFP, closer wavelength \\(CH21\& CH23 @ 1560.61 \& 1558.98 in SKA [7])
\end{itemize} \end{itemize}
\column{0.45\textwidth} \column{0.45\textwidth}
\begin{center}\vspace{-0.5cm} \begin{center}\vspace{-0.5cm}
\includegraphics<4>[width=0.6\textwidth]{measurements/sfp-temp-dependence.jpg} \includegraphics<3>[width=0.6\textwidth]{measurements/sfp-temp-dependence.jpg}
\includegraphics<5-6>[width=\textwidth]{measurements/fiber-temp-dependency.jpg} \includegraphics<4-5>[width=\textwidth]{measurements/fiber-temp-dependency.jpg}
\includegraphics<7>[width=\textwidth]{applications/SKA-DWDM.jpg} \includegraphics<6>[width=\textwidth]{applications/SKA-DWDM.jpg}
% \tiny\pause\pause\pause % \tiny\pause\pause\pause
% Figure source: [1] % Figure source: [1]
\end{center} \end{center}
...@@ -465,70 +505,323 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -465,70 +505,323 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
\begin{frame}{Frequency transfer} \begin{frame}{Frequency transfer}
\begin{center}\vspace{-0.3cm} \begin{center}\vspace{-0.3cm}
\includegraphics[height=2.3cm]{misc/inaccuracy-sources-freq-transfer.jpg}\\ \includegraphics[height=2.3cm]{misc/inaccuracy-sources-freq-transfer.jpg}\\
\includegraphics[width=.85\textwidth]{switch/wrs_v3_3_clocking.png} \includegraphics[width=.95\textwidth]{switch/wrs_v3_3_clocking_with_bandwidth.png}
\end{center} \end{center}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Frequency transfer} \begin{frame}{Frequency transfer}
\begin{center}\vspace{-0.3cm} % \begin{center}\vspace{-0.3cm}
\includegraphics[height=2.3cm]{misc/inaccuracy-sources-freq-transfer.jpg} % \includegraphics[height=2.3cm]{misc/inaccuracy-sources-freq-transfer.jpg}
% \end{center}
\begin{columns}[c]
\column{0.6\textwidth}\vspace{-0.5cm}
\begin{itemize}\scriptsize
\item<1-> \textbf{DDMTD}
\begin{itemize}\scriptsize
\item Flicker PM noise: -100 dBc at 1 Hz
\begin{itemize}\tiny
\item $<$ 10Hz, limits MDEV at $\tau=1s$ to 4E-13
\item LVDS input clock buffer and clock routing
\end{itemize}
\item White PM noise: -108 dBc
\begin{itemize}\tiny
\item Limits the phase noise to -108 dBc/Hz
\item Thermal, DFF meta-stability, noise due to aliasing
\end{itemize}
\item<2-> Stability at $\tau$=1s better on\\ Kintex-7 (28nm) \& Kintex US (20nm)
\end{itemize}
\item<3-> \textbf{GTX}
\begin{itemize}\scriptsize
\item Flicker PM noise: -97 dBc at 1 Hz
\item White PM noise: -106 dBc\\ MDEV at $\tau=1s$ to 4E-13
\end{itemize}
\end{itemize}
\column{0.5\textwidth}
\begin{center}\vspace{-0.5cm}
\includegraphics<1>[width=.99\textwidth]{measurements/DDMTD-noise.jpg}
\includegraphics<2>[width=.99\textwidth]{measurements/DDMTD-future-tech-noise.jpg}
\end{center} \end{center}
\end{columns}
\begin{center}
\tiny All above data is based on [13]
\end{center}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Frequency transfer}
% \begin{center}\vspace{-0.3cm}
% \includegraphics[height=2.3cm]{misc/inaccuracy-sources-freq-transfer.jpg}
% \end{center}
\vspace{0.5cm}
\begin{columns}[c] \begin{columns}[c]
\column{0.7\textwidth}\vspace{-0.5cm} \column{0.67\textwidth}\vspace{-0.5cm}
\begin{itemize}\scriptsize \begin{itemize}\scriptsize
\item \textbf{External reference input} -- noise \item<1-> Accumulation of phase noise in lower frquencies
\item \textbf{FPGA \& DDMTD} -- noise \item<2-> \textbf{VCXO}
\item \textbf{VCXO} -- nose \begin{itemize}\scriptsize
\end{itemize} \item Phase noise leaking from the local oscillator
\item Instabilities induced by cooling airflow
\item Remedy: increase bandwidth (see [14]) or better oscillator (see daughterboard [15])
\end{itemize}
\item<3->\textbf{External reference input}
\begin{itemize}\scriptsize
\item Noisy internal MMCM PLL
\item Large phase noise power at 10kHz to 2MHz
\item Remedy: external PLL to sythesize 62.5MHz from 10MHz (see daughterboard [15])
\end{itemize}
\column{0.45\textwidth}
\begin{center}\vspace{-0.5cm} \end{itemize}
\begin{table}[ht]
\centering
\tiny
\begin{tabular}{|l | c | c | c | c | c | } \hline \tiny
\textbf{Meas.} & \multicolumn{5}{|c|}{\textbf{Allan Deviation (ADEV)}} \\ \cline{2-6}
\textbf{at} & $\tau$=0.01 s & $\tau$=0.1 s & $\tau$=1 s & $\tau$=10 s & $\tau$=100 s \\ \cline{2-6}
& [s] & [s] & [s] & [s] & [s] \\ \hline
GM & 9.2e-10 & 1.3e-10 & 1.3e-11 & 1.3e-12 & 1.3e-13 \\ \hline
SW 1 & 7.4e-10 & 1.6e-10 & 1.9e-11 & 1.9e-12 & 1.9e-13 \\ \cline{1-6}
SW 2 & 6.9e-10 & 2.1e-10 & 2.7e-11 & 2.6e-12 & 2.6e-13 \\ \cline{1-6}
\end{tabular}
% \caption{Allan Deviation, equivalent noise bandwidth of 50Hz.}
\label{tab:adev}
\end{table}%\vspace{-0.3cm}
\column{0.5\textwidth}
\begin{center}\vspace{-0.5cm}\vspace{0.5cm}
\includegraphics<1-2>[width=.99\textwidth]{measurements/phase_noise_v3_4.pdf}
\includegraphics<3>[width=1.08\textwidth]{switch/mmcm_noise.png}
\includegraphics<4>[width=.45\textheight, angle=90]{measurements/WRSlowJitter/rsz_3d_image__1_.jpg}
\tiny
\begin{table}[!ht]
\centering
\tiny
\begin{tabular}{| l | c | c | c |} \hline \tiny
\textbf{Meas.} & \multicolumn{3}{|c|}{\textbf{RMS jitter}} \\ \cline{2-4}
\textbf{at} & \textbf{1Hz-10Hz} & \textbf{1Hz-2kHz} & \textbf{1Hz-100kHz} \\ \hline
GM & 4.7ps & 9.0ps & 9.1ps \\ \hline
SW 1 & 7.1ps & 11.0ps & 11.0ps \\ \cline{1-4}
SW 2 & 8.8ps & 14.0ps & 14.0ps \\ \hline
\end{tabular}
% \caption{Integrated RMS jitter in different regions of the spectrum.}
\label{tab:phaseNoise}
\end{table}%\vspace{-0.3cm}
\end{center} \end{center}
\end{columns} \end{columns}
\begin{center}
\tiny Data from [14]
\end{center}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{} \begin{frame}{Test setup for switch with Low Jitter Daughterboard}
\begin{frame}{Performance Enhancements} \begin{center}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \includegraphics[width=\textwidth]{measurements/WRSlowJitter/rsz_experimental_setup.png}\\
\begin{itemize}\footnotesize \tiny See more: [15]
\item<1-> Compensation of hardware temperature variation \end{center}
\begin{itemize}\scriptsize \end{frame}
\item Triggered by cosmic ray detectors
\item Active correction of hardware temperature variation
\item Pk-pk variation from 700 ps to \textbf{$<$150 ps with sdev $<$50ps (-10 to 50$^o$C)} %
\end{itemize} % \begin{frame}{Improvements for GM: PM noise and Modified ADEV}
\item<2-> Link asymmetry correction % \begin{center}
\begin{itemize}\scriptsize % \includegraphics[width=.5\textwidth]{measurements/WRSlowJitter/pn.png}
\item Triggered by radio telescope (Square Kilometre Array) % \includegraphics[width=.5\textwidth]{measurements/WRSlowJitter/mdev.png}
\item At 1310/1490nm, temp variation -0.12 ps/km/K (3ns for 80km over 50$^o$C) % \end{center}
\item \textbf{Sub-ns for 80km over 50$^o$C} using DWDM SFP on ITU channels C21/C22 (1560.61/1558.98 nm) % \begin{itemize}\scriptsize
\end{itemize} % \item Jitter improvement: 9ps to $<$2ps RMS 10Hz-100kHz
\item<3-> Absolute calibration % \item ADEV improvement: 1.4E-11 to $<$5E-13 $\tau$=1s ENBW 50Hz
\begin{itemize}\scriptsize % \end{itemize}
\item Triggered by % \end{frame}
\item
\item \begin{frame}{Switch with LJD: PM noise and Modified ADEV}
\end{itemize} \vspace{-0.5cm}
\item<4-> Long-haul link \begin{center}
\begin{itemize}\scriptsize \includegraphics[width=.5\textwidth]{measurements/WRSlowJitter/GM+BC_pn.jpg}
\item Triggered by National Time Labs and Radio Telescope \includegraphics[width=.45\textwidth]{measurements/WRSlowJitter/GM+BC_MDEV.jpg}
\item \textbf{Sub-ns} is achievable on links on \textbf{up to 80km} \end{center}
\item \textbf{Ns on 137km} bidirectional \& \textbf{$\pm$2.5ns on 950km} unidirectional links \begin{itemize}\scriptsize
\end{itemize} \item Jitter improvement [13, 15]
\item<5-> Jitter and clock stability (next slide) \begin{itemize}\scriptsize
\item GM: 9ps to $<$2ps RMS 10Hz-100kHz
\item BC:
\end{itemize}
\item ADEV improvement [13, 15]
\begin{itemize}\scriptsize
\item GM: 1.4E-11 to $<$5E-13 $\tau$=1s ENBW 50Hz
\item BC:
\end{itemize}
\end{itemize} \end{itemize}
\end{frame}
\section{Current developments}
\subsection{}
\begin{frame}{Current developments}
\begin{itemize}\small
\item<1-> Standardization in IEEE 1588:
\begin{itemize}\scriptsize
\item High Accuracy sub-committee in dedicated to WR
\item WR to become Default High Accuracy Profile
\item Revised standard expected in 2019.
\end{itemize}
\item<2-> Long-haul link
\begin{itemize}\scriptsize
\item Triggered by National Time Labs and Radio Telescope
\item \textbf{Sub-ns} is achievable on links on \textbf{up to 80km}
\item \textbf{Ns on 137km} bidirectional \& \textbf{$\pm$2.5ns on 950km} unidirectional links
\end{itemize}
\item<3-> Absolute Calibration
\item<4-> WR-based applications
\begin{itemize}\scriptsize
\item Better diagnostics and remote management of WR networks
\item Radio-frequency over WR for RF cavities control
\item Distributed Oscilloscope
\end{itemize}
\end{itemize}
\end{frame} \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % \begin{frame}{Current developments}
% \begin{block}{Switches and nodes are commercially available}
% Work now revolves around better diagnostics and remote management of WR
% networks as well as improving the phase noise and performing extensive network stress tests.
% \end{block}
% \pause
% \begin{block}{Standardisation}
% IEEE 1588 revision process is ongoing and contains a sub-committee (High
% Accuracy) dedicated to White Rabbit. Revised standard expected in 2019.
% \end{block}
% \pause
% \begin{block}{Robustness}
% Based on redundant information and fast switch-over between
% redundant fibres and switches.
% \end{block}
% \end{frame}
%
\begin{frame}{RF over WR a.k.a. Distributed DDS}
\begin{center}
\includegraphics[width=\columnwidth]{applications/remote_dds.pdf}
\end{center}
\begin{block}{Distributed Direct Digital Synthesis}
\begin{itemize}
\item Replaces dozens of cables with a single fiber.
\item Works over big distances without degrading signal quality.
\item Can provide various clocks (RF of many rings and linacs) with a single, standard link.
\item At CERN, it requires distribution of 200 MHz RF with 0.25ps RM jitter and $\pm$10ps accuracy.
\end{itemize}
\end{block}
\end{frame}
\begin{frame}{Distributed oscilloscope}
\begin{center}
\includegraphics[width=0.9\textwidth]{applications/distr_oscill.pdf}
\end{center}
\begin{block}{}
\begin{itemize}
\item Common clock in entire network: no skew between ADCs.
\item Ability to sample with different clocks via Distributed DDS.
\item External triggers can be time tagged with a TDC and used to reconstruct the original time base in the operator's PC.
\end{itemize}
\end{block}
\end{frame}
\section{Conclusions}
\subsection{} \subsection{}
\begin{frame}{Performance Enhancements}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{frame}{Summary}
\begin{itemize}
\item Scientific, open (H/W \& S/W), with commercial support
\pause
\item Standard-compatible and standard-extending
\pause
\item More applications than ever expected
\pause
\item A versatile solution for general control and data acquisition
\pause
\item Substantial improvements in performance
\pause
\item Active participation in IEEE1588 revision process
\end{itemize}
% \pause
%For more information see http://www.ohwr.org/projects/white-rabbit/wiki
\end{frame}
\begin{frame}{Need more information?}
\begin{center}
\includegraphics[height=4.0cm]{misc/white_rabbit_end.png}
\end{center}
\begin{center}
http://www.ohwr.org/projects/white-rabbit/wiki
\end{center}
\end{frame}
\appendix
\backupbegin
\begin{frame}{References}
\tiny
\begin{enumerate}
\item \textbf{White Rabbit Project:}\url{https://www.ohwr.org/project/white-rabbit/wikis}
\item \textbf{Companies selling WR:}\url{https://www.ohwr.org/project/white-rabbit/wrcompanies}
\item \textbf{Users of WR:}\url{https://www.ohwr.org/project/white-rabbit/WRUsers}
\item \textbf{White Rabbit Applications and Enhancements}, M.Lipinski et. al, ISPCS2018\\\url{https://www.ohwr.org/project/white-rabbit/uploads/7f9e67258850d5c036629a509bf2e124/ISPCS2018-WRApplicatoinsAndEnhancements.pdf}
\item \textbf{White Rabbit Newsletter, September 2018} \\\url{https://www.ohwr.org/project/white-rabbit/wikis/newsletter-2018-09}
\item \textbf{Temperature Effect and Correction Method of White Rabbit Timing Link}; Hongming Li, Guanghua Gong, Weibin Pan, Qiang Du, Jianmin Li
\item \textbf{DWDM Stabilized Optics for White Rabbit}, Paul Boven
\item \textbf{WR Calibration}, version 1.1, G.Daniluk\\ \url{www.cern.ch/white-rabbit/documents/WR_Calibration-v1.1-20151109.pdf}
\item \textbf{White Rabbit Switch:} \url{https://www.ohwr.org/project/white-rabbit/wikis/Switch}
\item \textbf{White Rabbit Node:} \url{https://www.ohwr.org/project/white-rabbit/wikis/Node}
\item \textbf{White Rabbit PTP Core:} \url{https://www.ohwr.org/project/wr-cores/wikis/Wrpc-core}
\item \textbf{White Rabbit: a PTP application for robust sub-nanosecond synchronization}, M. Lipiński et el, ISPCS2011\\\url{https://www.ohwr.org/project/white-rabbit/uploads/cfc34350adcbf5156f968fac0b9301b5/ISPCS2011_WR.pdf}
\item \textbf{White Rabbit Clock Synchronization: Ultimate Limits on Close-In Phase Noise and Short-Term Stability Due to FPGA Implementation}, M.Rizzi et el, UFFC-T, 2018\\\url{https://www.ohwr.org/project/white-rabbit/uploads/253cbfc17d2b43cd445b68348aee0374/Submitted_IEEE.pdf}
\item \textbf{White Rabbit Clock Characteristics}, M. Rizzi et el, ISPCS2016\\\url{https://www.ohwr.org/project/white-rabbit/uploads/2fa1a438446fc6c85b4540faecf1017a/ISPCS2016-WRClockCharacteristics.pdf}
\item \textbf{WRS Low Jitter Daughterboard:}\url{www.ohwr.org/projects/wrs-low-jitter}
\end{enumerate}
\end{frame}
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% \subsection{}
% \begin{frame}{Performance Enhancements}
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% \begin{itemize}\footnotesize
% \item<1-> Compensation of hardware temperature variation
% \begin{itemize}\scriptsize
% \item Triggered by cosmic ray detectors
% \item Active correction of hardware temperature variation
% \item Pk-pk variation from 700 ps to \textbf{$<$150 ps with sdev $<$50ps (-10 to 50$^o$C)}
% \end{itemize}
% \item<2-> Link asymmetry correction
% \begin{itemize}\scriptsize
% \item Triggered by radio telescope (Square Kilometre Array)
% \item At 1310/1490nm, temp variation -0.12 ps/km/K (3ns for 80km over 50$^o$C)
% \item \textbf{Sub-ns for 80km over 50$^o$C} using DWDM SFP on ITU channels C21/C22 (1560.61/1558.98 nm)
% \end{itemize}
% \item<3-> Absolute calibration
% \begin{itemize}\scriptsize
% \item Triggered by
% \item
% \item
% \end{itemize}
% \item<4-> Long-haul link
% \begin{itemize}\scriptsize
% \item Triggered by National Time Labs and Radio Telescope
% \item \textbf{Sub-ns} is achievable on links on \textbf{up to 80km}
% \item \textbf{Ns on 137km} bidirectional \& \textbf{$\pm$2.5ns on 950km} unidirectional links
% \end{itemize}
% \item<5-> Jitter and clock stability (next slide)
% \end{itemize}
%
% \end{frame}
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% \subsection{}
% \begin{frame}{Performance Enhancements}
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% \begin{itemize}\scriptsize % \begin{itemize}\scriptsize
% \item The short-term performance of WR % \item The short-term performance of WR
% time-transfer directly depends on two design choices of the % time-transfer directly depends on two design choices of the
...@@ -612,152 +905,47 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline ...@@ -612,152 +905,47 @@ INRIM & Italy & 70~km & 610ps $\pm$47ps\\ \hline
% \end{itemize} % \end{itemize}
\end{frame} % \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{} % \subsection{}
\begin{frame}{Performance Enhancements} % \begin{frame}{Performance Enhancements}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{itemize}\scriptsize % \begin{itemize}\scriptsize
\item Triggered by National Laboratories and RF distribution % \item Triggered by National Laboratories and RF distribution
\item Allan deviation (ADEV) from 1e-11 to \textbf{1e-12} over 1s % \item Allan deviation (ADEV) from 1e-11 to \textbf{1e-12} over 1s
\item Random jitter from 11 to \textbf{1.1ps RMS} (1 Hz to 100kHz) % \item Random jitter from 11 to \textbf{1.1ps RMS} (1 Hz to 100kHz)
\item Ongong work to achieve jitter of \textbf{sub-100fs RMS} (100Hz to 20MHz) % \item Ongong work to achieve jitter of \textbf{sub-100fs RMS} (100Hz to 20MHz)
\end{itemize} % \end{itemize}
%
\end{frame} % \end{frame}
%
\begin{frame}{Test setup for 10MHz switch output} % \begin{frame}{WR switch clocking scheme}{Thanks to Mattia Rizzi for the work and
\begin{center} % the figures in this section}
\includegraphics[width=\textwidth]{measurements/WRSlowJitter/rsz_experimental_setup.png} % \begin{center}
\end{center} % \includegraphics[width=.85\textwidth]{switch/wrs_v3_3_clocking.png}
\end{frame} % \end{center}
% \end{frame}
\begin{frame}{WR switch clocking scheme}{Thanks to Mattia Rizzi for the work and %
the figures in this section} % \begin{frame}{MMCM noise}
\begin{center} % \begin{center}
\includegraphics[width=.85\textwidth]{switch/wrs_v3_3_clocking.png} % \includegraphics[height=.7\textheight]{switch/mmcm_noise.png}
\end{center} % \end{center}
\end{frame} % \end{frame}
%
\begin{frame}{MMCM noise} % \begin{frame}{WR Switch: low jitter daughterboard}
\begin{center} % \begin{columns}
\includegraphics[height=.7\textheight]{switch/mmcm_noise.png} % \column{.35\textwidth}
\end{center} % \includegraphics[width=.8\textheight, angle=90]{measurements/WRSlowJitter/rsz_3d_image__1_.jpg}
\end{frame} % \column{.65\textwidth}
% \begin{itemize}
\begin{frame}{WR Switch: low jitter daughterboard} % \item Current release of WRS in GM mode has sub-optimal performance on both jitter (9ps RMS 1Hz-100kHz) and ADEV (1.4E-11 $\tau$=1s ENBW 50Hz)
\begin{columns} % \item A daughterboard was designed, produced and tested to improve the performance
\column{.35\textwidth} % \item Modified WRS improves performance on both jitter ($<$2ps RMS 10Hz-100kHz) and ADEV ($<$5E-13 $\tau$=1s ENBW 50Hz) in GM mode
\includegraphics[width=.8\textheight, angle=90]{measurements/WRSlowJitter/rsz_3d_image__1_.jpg} % \end{itemize}
\column{.65\textwidth} % \end{columns}
\begin{itemize} % \end{frame}
\item Current release of WRS in GM mode has sub-optimal performance on both jitter (9ps RMS 1Hz-100kHz) and ADEV (1.4E-11 $\tau$=1s ENBW 50Hz)
\item A daughterboard was designed, produced and tested to improve the performance
\item Modified WRS improves performance on both jitter ($<$2ps RMS 10Hz-100kHz) and ADEV ($<$5E-13 $\tau$=1s ENBW 50Hz) in GM mode \backupend
\end{itemize}
\end{columns}
\end{frame}
\begin{frame}{Test Results in GM mode: PM noise}
\begin{center}
\includegraphics[height=.85\textheight]{measurements/WRSlowJitter/pn.png}
\end{center}
\end{frame}
\begin{frame}{Test Results in GM mode: Modified ADEV}
\begin{center}
\includegraphics[height=.85\textheight]{measurements/WRSlowJitter/mdev.png}
\end{center}
\end{frame}
\section{Current developments}
\subsection{}
\begin{frame}{Current developments}
\begin{block}{Switches and nodes are commercially available}
Work now revolves around better diagnostics and remote management of WR
networks as well as improving the phase noise and performing extensive network stress tests.
\end{block}
\pause
\begin{block}{Standardisation}
IEEE 1588 revision process is ongoing and contains a sub-committee (High
Accuracy) dedicated to White Rabbit. Revised standard expected in 2019.
\end{block}
\pause
\begin{block}{Robustness}
Based on redundant information and fast switch-over between
redundant fibres and switches.
\end{block}
\end{frame}
\begin{frame}{Ethernet Clock distribution a.k.a. Distributed DDS}
\begin{center}
\includegraphics[width=\columnwidth]{applications/remote_dds.pdf}
\end{center}
\begin{block}{Distributed Direct Digital Synthesis}
\begin{itemize}
\item Replaces dozens of cables with a single fiber.
\item Works over big distances without degrading signal quality.
\item Can provide various clocks (RF of many rings and linacs)
with a single, standard link.
\end{itemize}
\end{block}
\end{frame}
\begin{frame}{Distributed oscilloscope}
\begin{center}
\includegraphics[width=0.9\textwidth]{applications/distr_oscill.pdf}
\end{center}
\begin{block}{}
\begin{itemize}
\item Common clock in entire network: no skew between ADCs.
\item Ability to sample with different clocks via Distributed DDS.
\item External triggers can be time tagged with a TDC and used to reconstruct the original time base in the operator's
PC.
\end{itemize}
\end{block}
\end{frame}
\section{Conclusions}
\subsection{}
\begin{frame}{Summary}
\begin{itemize}
\item Scientific, open (H/W \& S/W), with commercial support
\pause
\item More applications than ever expected
\pause
\item A versatile solution for general control and data acquisition
\pause
\item Standard-compatible and standard-extending
\pause
\item Active participation in IEEE1588 revision process
\end{itemize}
% \pause
%For more information see http://www.ohwr.org/projects/white-rabbit/wiki
\end{frame}
\begin{frame}{Need more information?}
\begin{center}
\includegraphics[height=4.0cm]{misc/white_rabbit_end.png}
\end{center}
\begin{center}
http://www.ohwr.org/projects/white-rabbit/wiki
\end{center}
\end{frame}
\begin{frame}{References}
\tiny
\begin{itemize}
\item White Rabbit Project:\\\url{https://www.ohwr.org/project/white-rabbit/wikis}
\item Companies selling WR:\\\url{https://www.ohwr.org/project/white-rabbit/wrcompanies}
\item Users of WR:\\\url{https://www.ohwr.org/project/white-rabbit/WRUsers}
\item White Rabbit Applications and Enhancements, M.Lipinski et. al, ISPCS2018\\\url{https://www.ohwr.org/project/white-rabbit/uploads/7f9e67258850d5c036629a509bf2e124/ISPCS2018-WRApplicatoinsAndEnhancements.pdf}
\item WR Calibration, version 1.1, G.Daniluk\\ \url{www.cern.ch/white-rabbit/documents/WR_Calibration-v1.1-20151109.pdf}
\item \textit{Temperature Effect and Correction Method of White Rabbit Timing Link}; Hongming Li, Guanghua Gong, Weibin Pan, Qiang Du, Jianmin Li
\item \textit{DWDM Stabilized Optics for White Rabbit}, Paul Boven
\end{itemize}
\end{frame}
\end{document} \end{document}
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment