diff --git a/chapter-sampling-mesh-monitor/chapter.tex b/chapter-sampling-mesh-monitor/chapter.tex index e61c4f6..bfa0cad 100644 --- a/chapter-sampling-mesh-monitor/chapter.tex +++ b/chapter-sampling-mesh-monitor/chapter.tex @@ -753,7 +753,47 @@ its switching happens in the short period between its input differential voltage combined forward voltage of the Schottky diodes. Thus, while the \partno{74LVC} might produce slow edges overall, its large output swing results in a high slew rate in the critical region around the zero crossing. -We observed the best result overall with the \partno{PI3HDX12211} redriver, resulting in a rise time of +\begin{figure} + \begin{center} + \begin{subfigure}{0.45\textwidth} + \centering + \includegraphics[width=\textwidth]{edge_sampling_pulse_scope.pdf} + \vspace*{-5mm} + \caption{Sampling pulse} + \label{fig_osc_risetime_samp} + \end{subfigure} + \unskip\begin{subfigure}{0.45\textwidth} + \centering + \includegraphics[width=\textwidth]{edge_stimulus_pulse_scope_normalized.pdf} + \vspace*{-5mm} + \caption{Stimulus pulse} + \label{fig_osc_risetime_stim} + \end{subfigure} + \end{center} + \vspace*{-5mm} + \caption[Pulse risetime oscilloscope measurements]{Oscilloscope measurements of the sampling pulse probed + differentially (left) and of the stimulus pulse probed single-ended and normalized (right). The 74LVC pulse is + plotted on the right Y axis in the left plot due to its large amplitude. In the right plot, it is not shown + since our measurement setup did not allow for a measurement of this amplitude.} + \label{fig_osc_risetime} +\end{figure} + +Figure~\ref{fig_osc_risetime} shows the sampling and stimulus pulse edges measured using a Siglent SDS7404A +\qty{4}{\giga\hertz} oscilloscope. The stimulus pulse was directly measured single-ended, and the sampaling pulse was +measured differentially through a Siglent SAP2500D \qty{2.5}{\giga\hertz} active differential probe. These measurements +support the conclusion from Figure~\ref{fig_spec_risetime} that in raw edge risetime, \partno{MAX3748} and +\partno{TDP0604} perform fastest, with \partno{PI3HDX12211} being slightly slower. They also exhibit the large +differences in amplitude that we expect cause the differences in actual measurement performance as shwon in +Figure~\ref{fig_edge_risetime}. Note that due to the differences in measurement methodology, a direct comparison of the +rise times is not possible between these plots. The spectrum measurements do not convey amplitude information and +discard low-frequency content, but due to the very large bandwidth of the spectrum analyzer used, they will represent +the true risetime the closest. In both the self-characterization and the oscilloscope measurements, the displayed +risetime is contaminated by the measurement system. In case of the self-characterization, the stimmulus rise time is +folded into the measurement result, leading in the displayed risetime being slower by a factor of $\sqrt{2}$. Similarly, +in the oscilloscope measurements, the combined risetime of the oscilloscope frontend and active probe contaminate the +results. + +We observed the best overall performance with the \partno{PI3HDX12211} redriver, resulting in a rise time of \qty{264}{\pico\second}. In this test specimen, we fed the pulse through the amplifier twice since we had two unused channels, and we used \qty{200}{\pico\second} clip lines on the amplifier's output for pulse shaping. We only used clip lines here and for \partno{TDP0604} since the other amplifiers' output did not contain sufficient harmonic content. diff --git a/chapter-sampling-mesh-monitor/figures/edge_sampling_pulse_scope.pdf b/chapter-sampling-mesh-monitor/figures/edge_sampling_pulse_scope.pdf new file mode 100644 index 0000000..baa45bd Binary files /dev/null and b/chapter-sampling-mesh-monitor/figures/edge_sampling_pulse_scope.pdf differ diff --git a/chapter-sampling-mesh-monitor/figures/edge_stimulus_pulse_scope_normalized.pdf b/chapter-sampling-mesh-monitor/figures/edge_stimulus_pulse_scope_normalized.pdf new file mode 100644 index 0000000..8d43eec Binary files /dev/null and b/chapter-sampling-mesh-monitor/figures/edge_stimulus_pulse_scope_normalized.pdf differ diff --git a/chapter-sampling-mesh-monitor/figures/sampling-mesh-monitor b/chapter-sampling-mesh-monitor/figures/sampling-mesh-monitor index b4dc582..cd33cff 160000 --- a/chapter-sampling-mesh-monitor/figures/sampling-mesh-monitor +++ b/chapter-sampling-mesh-monitor/figures/sampling-mesh-monitor @@ -1 +1 @@ -Subproject commit b4dc58286d039b1d0f70ea86f9e1f2cc538d8fbb +Subproject commit cd33cff0e8b3284f26a4b87c9c9d40ae226dceed