Commit d1781571 authored by Javier Serrano's avatar Javier Serrano

Added Mattia's work on switch jitter improvements

parent e2c4e5cc
...@@ -136,6 +136,9 @@ $ S_{\varphi}(f) \approx \frac{2}{T} \left< \left| \Phi_T(f) \right| ^2 \right>_ ...@@ -136,6 +136,9 @@ $ S_{\varphi}(f) \approx \frac{2}{T} \left< \left| \Phi_T(f) \right| ^2 \right>_
\includegraphics[width=\textwidth]{misc/onesided_psd.pdf} \includegraphics[width=\textwidth]{misc/onesided_psd.pdf}
} }
% Include slides on 5052B and TimePod operating principles.
% Also slide on ADEV
\section{Background on phase-locked loops} \section{Background on phase-locked loops}
\subsection{} \subsection{}
...@@ -157,11 +160,11 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $ ...@@ -157,11 +160,11 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $
\end{block} \end{block}
} }
\frame{\frametitle{Jitter optimization} \frame{\frametitle{Jitter optimisation}
\includegraphics[height=0.7\textwidth]{misc/pll_psd.pdf} \includegraphics[height=0.7\textwidth]{misc/pll_psd.pdf}
} }
\section{Performance} \section{White Rabbit case}
\subsection{} \subsection{}
\begin{frame}{WR time transfer performance: basic test setup} \begin{frame}{WR time transfer performance: basic test setup}
...@@ -171,14 +174,55 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $ ...@@ -171,14 +174,55 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $
\end{frame} \end{frame}
\begin{frame}{WR time transfer performance: test results} \begin{frame}{Basic oscilloscope measurements}{How do they relate to
phase noise?}
\begin{center} \begin{center}
\includegraphics[height=6.0cm]{measurements/meas_results2.pdf} \includegraphics[height=6.0cm]{measurements/meas_results2.pdf}
\end{center} \end{center}
\end{frame} \end{frame}
\begin{frame}{How to drive the phase noise PSD curve down?}
\begin{block}{Medium and high (Fourier) frequencies}
Easy! Just buy a better oscillator. OCXO-based node in development
at CERN achieves 100fs jitter (100Hz-5MHz).
\end{block}
\begin{block}{Low (Fourier) frequencies}
Tricky. Usually involves serious architectural changes. See next.
\end{block}
\end{frame}
\begin{frame}{Digital Dual Mixer Time Difference}{DDMTD}
\begin{itemize}
\item Used for precise phase measurements
\item Implemented in FPGA and SoftPLL
\item 62.5MHz WR clock and N=14 results in 3.814kHz output signals
\end{itemize}
\vspace{-0.2cm}
\begin{center}
\includegraphics[width=\textwidth]{misc/dmtd_2N.pdf}
\end{center}
\end{frame}
\begin{frame}{Daughterboard Test Setup}
\begin{center}
\includegraphics[width=\textwidth]{measurements/WRSlowJitter/rsz_experimental_setup.png}
\end{center}
\end{frame}
\begin{frame}{WR switch clocking scheme}{Thanks to Mattia Rizzi for the work and
the figures in this section}
\begin{center}
\includegraphics[width=.85\textwidth]{switch/wrs_v3_3_clocking.png}
\end{center}
\end{frame}
\begin{frame}{MMCM noise}
\begin{center}
\includegraphics[height=.7\textheight]{switch/mmcm_noise.png}
\end{center}
\end{frame}
\begin{frame}{WR Switch: low jitter daughterboard} \begin{frame}{WR Switch: low jitter daughterboard}
\begin{columns} \begin{columns}
\column{.35\textwidth} \column{.35\textwidth}
...@@ -192,12 +236,6 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $ ...@@ -192,12 +236,6 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $
\end{columns} \end{columns}
\end{frame} \end{frame}
\begin{frame}{Daughterboard Test Setup}
\begin{center}
\includegraphics[width=\textwidth]{measurements/WRSlowJitter/rsz_experimental_setup.png}
\end{center}
\end{frame}
\begin{frame}{Test Results in GM mode: PM noise} \begin{frame}{Test Results in GM mode: PM noise}
\begin{center} \begin{center}
\includegraphics[height=.85\textheight]{measurements/WRSlowJitter/pn.png} \includegraphics[height=.85\textheight]{measurements/WRSlowJitter/pn.png}
...@@ -228,7 +266,7 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $ ...@@ -228,7 +266,7 @@ $ E(s) = 1 - H(s) = \frac{s}{s + K_{VCO} K_d F(s)} $
\end{center} \end{center}
\begin{center} \begin{center}
See \url{https://www.ohwr.org/attachments/2939/timing.pdf} and \url{https://www.ohwr.org/projects/wr-low-jitter/wiki} See \url{https://www.ohwr.org/attachments/2939/timing.pdf} and \url{https://www.ohwr.org/projects/w2r-low-jitter/wiki}
\end{center} \end{center}
\end{frame} \end{frame}
......
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