Commit d1781571 by Javier Serrano

### Added Mattia's work on switch jitter improvements

parent e2c4e5cc

35.3 KB

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