From b476c178d0a7f2abb8e55daf10e6dfb5bb3864f7 Mon Sep 17 00:00:00 2001
From: occheung <dc@m-labs.hk>
Date: Tue, 8 Feb 2022 13:33:53 +0800
Subject: [PATCH] 2118-2128: add min pulse width spec

Especially test reuslt that validate the "minimum 3ns pulse width" claim.
---
 2118-2128.tex | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/2118-2128.tex b/2118-2128.tex
index affcc4a..beebe51 100644
--- a/2118-2128.tex
+++ b/2118-2128.tex
@@ -347,6 +347,7 @@ The card support a minimum pulse width of 3ns.
 All specifications are in $0\degree C \leq T_A \leq 70\degree C$ unless otherwise noted.
 Specifications are based on the bus transceivers IC (SN74BCT25245DW\footnote{\label{transceiver}https://www.ti.com/lit/ds/symlink/sn74bct25245.pdf})
 and the isolator IC (SI8651BB-B-IS1\footnote{\label{isolator}https://www.skyworksinc.com/-/media/Skyworks/SL/documents/public/data-sheets/si865x-datasheet.pdf}).
+The typical value of minimum pulse width is based on test results\footnote{\label{sinara187}https://github.com/sinara-hw/sinara/issues/187}.
 
 \begin{table}[h]
 \begin{threeparttable}
@@ -385,6 +386,8 @@ and the isolator IC (SI8651BB-B-IS1\footnote{\label{isolator}https://www.skywork
     Low-level output voltage\repeatfootnote{transceiver} & $V_{OL}$ & & 0.42 & 0.55 & V & $I_{OL}$=188mA \\
     &  &  &  & 0.7 & V & $I_{OL}$=376mA \\
     \hline
+    Minimum pulse width\repeatfootnote{isolator}\textsuperscript{,}\repeatfootnote{sinara187} & & & 3 & 5 & ns & \\
+    \hline
     Pulse width distortion\repeatfootnote{isolator} & $PWD$ & & 0.2 & 4.5 & ns &  \\
     \hline
     Peak jitter\repeatfootnote{isolator} & $T_{JIT(PK)}$ & & 350 & & ps &  \\
@@ -397,6 +400,23 @@ and the isolator IC (SI8651BB-B-IS1\footnote{\label{isolator}https://www.skywork
 
 \newpage
 
+Minimum pulse width was measured\repeatfootnote{sinara187}.
+Pulses were generated from a DDS generator as an input of a BNC-TTL card.
+The input BNC-TTL card is connected to another BNC-TTL card as an output.
+The output signal is measured and shown.
+
+\begin{figure}[h]
+    \centering
+    \includegraphics[height=3in]{bnc_ttl_min_pulse_width.png}
+    \caption{Minimum pulse width required for BNC-TTL card}
+\end{figure}
+
+The red trace refers to the input pulses from the DDS generator, while the blue trace is the measured signal from the output BNC-TTL card.
+Note that the first input (red) pulse could not propagate through the signal chain.
+The first output (blue) pulse is the result of the second input (red, 3ns width) pulse.
+
+\newpage
+
 \section{Front Panel Drawings}
 
 \begin{multicols}{2}