diff options
author | Glenn Kasten <gkasten@google.com> | 2013-05-13 17:34:43 -0700 |
---|---|---|
committer | Android Git Automerger <android-git-automerger@android.com> | 2013-05-13 17:34:43 -0700 |
commit | b92401f9963acaf85563256a03d807fb2522630a (patch) | |
tree | 46032a92e75f4c6421a92257d4155f6fb3408f9d | |
parent | cb4cdd0fbf8bc93463cd7d3b9c5fef528237d094 (diff) | |
parent | 3ac311285de8b7459988f6e56705ae22e5a3743c (diff) | |
download | source.android.com-b92401f9963acaf85563256a03d807fb2522630a.tar.gz |
am 3ac31128: am 4fe3ba46: Add testing circuit
* commit '3ac311285de8b7459988f6e56705ae22e5a3743c':
Add testing circuit
-rw-r--r-- | src/devices/devices_toc.cs | 1 | ||||
-rw-r--r-- | src/devices/image1.jpg | bin | 0 -> 35965 bytes | |||
-rw-r--r-- | src/devices/image2.jpg | bin | 0 -> 51238 bytes | |||
-rw-r--r-- | src/devices/image3.jpg | bin | 0 -> 36193 bytes | |||
-rw-r--r-- | src/devices/testing_circuit.jd | 74 |
5 files changed, 75 insertions, 0 deletions
diff --git a/src/devices/devices_toc.cs b/src/devices/devices_toc.cs index 4e514b6b..59916fa2 100644 --- a/src/devices/devices_toc.cs +++ b/src/devices/devices_toc.cs @@ -37,6 +37,7 @@ <li><a href="<?cs var:toroot ?>devices/audio_avoiding_pi.html">Avoiding Priority Inversion</a></li> <li><a href="<?cs var:toroot ?>devices/latency_design.html">Design For Reduced Latency</a></li> <li><a href="<?cs var:toroot ?>devices/audio_terminology.html">Terminology</a></li> + <li><a href="<?cs var:toroot ?>devices/testing_circuit.html">Testing Circuit</a></li> </ul> </li> <li><a href="<?cs var:toroot ?>devices/camera.html">Camera v1</a></li> diff --git a/src/devices/image1.jpg b/src/devices/image1.jpg Binary files differnew file mode 100644 index 00000000..f98422f7 --- /dev/null +++ b/src/devices/image1.jpg diff --git a/src/devices/image2.jpg b/src/devices/image2.jpg Binary files differnew file mode 100644 index 00000000..10a2789a --- /dev/null +++ b/src/devices/image2.jpg diff --git a/src/devices/image3.jpg b/src/devices/image3.jpg Binary files differnew file mode 100644 index 00000000..9748ec3a --- /dev/null +++ b/src/devices/image3.jpg diff --git a/src/devices/testing_circuit.jd b/src/devices/testing_circuit.jd new file mode 100644 index 00000000..93ee06ad --- /dev/null +++ b/src/devices/testing_circuit.jd @@ -0,0 +1,74 @@ +page.title=Testing Circuit +@jd:body + +<div id="qv-wrapper"> + <div id="qv"> + <h2>In this document</h2> + <ol id="auto-toc"> + </ol> + </div> +</div> + +<p> +The file <a href="http://developer.android.com/downloads/partner/audio/av_sync_board.zip">av_sync_board.zip</a> +contains CAD files for an A/V sync and latency testing +printed circuit board (PCB). +The files include a fabrication drawing, EAGLE CAD, schematic, and BOM. +</p> + +<p> +This PCB +can be used to help measure the time between flashing the device's +notification LED or screen backlight, vs. detecting an audio signal. +When combined with a dual-channel oscilloscope and suitable test app, +it can show the difference in time between detecting the light and audio. +That assumes the LED or backlight response time and light detector's response time +are negligible relative to the audio. +</p> + +<p> +This design is supplied "as is", and we aren't be responsible for any errors in the design. +But if you have any suggestions for improvement, please post to android-porting group. +</p> + +<p> +Of course, this is not the only (or necessarily best) way to measure A/V sync and latency, +and we would like to hear about your alternative methods, also at android-porting group. +</p> + +<p> +There are currently no compatibility requirements to use this particular PCB. +We supply it to encourage your continued attention to audio performance. +</p> + +<h2 id="images">Images</h2> + +<p> +These photos show the circuit in action. +</p> + +<img style="margin:1.5em auto" src="image1.jpg" alt="breadboard prototype" /> +<br /> +<center>Breadboard prototype</center> + +<img style="margin:1.5em auto" src="image2.jpg" alt="an early run of the PCB" /> +<br /> +<center>An early run of the PCB</center> + +<img style="margin:1.5em auto" src="image3.jpg" alt="example display"> +<br /> +<center>Example display</center> +<p> +This image +shows the scope display for an unspecified device, software release, and test conditions; +the results are not typical and cannot be used to extrapolate to other situations. +</p> + +<h2 id="video">Video</h2> + +<p> +This <a href="http://www.youtube.com/watch?v=f95S2IILBJY">Youtube video</a> +shows the the breadboard version testing circuit in operation. +Skip ahead to 1:00 to see the circuit. +</p> + |