Scripts and Automation: MP3 player test

A complete example dScope Series III .dss script that can be used for testing MP3 players and related playback devices. It uses a short test sequence to make 18 measurements in around 6 seconds. Zip file containing installer, documentation, and test tracks.

The MP3 player script tests a range of parameters very rapidly, indicates Pass or Fail, and saves the results to a spreadsheet. The basic principle is that the player is connected to the analogue inputs of the dScope and a test signal played from the MP3 player. The test signal consists of three sections:

-3dBFS 1kHz Sine on both channels
-60dBFS 1kHz Sine on both channels
Special 5 tone Multi-tone.

The script recognises the start of the audio and keeps in step with these stages. It makes a total of 18 measurements in typically about 6 seconds (depending on the signal itself and the speed of the computer running the dScope software).

INSTALLATION
The files are supplied in a zip file with a script installer which creates the necessary folders and copies files to the required location. This script reads the dScope installation folder location from the registry, then installs the necessary files, creating new folders where necessary. To install the files, unzip the contents of the zip file to an empty folder (location is not important) and double click on the file "install test files.vbs". This may get stopped by antivirus software as it uses the registry to get the path to the dScope folder. If so, you will need to tell the antivirus software to allow the script to run. Once it has run, it generates a text file called "report.txt" which lists the actions taken by the script, including where it has installed files. To un-install the scripts, you would need to look at this report and remove the files and folders it has copied and created. In this instance the installer may create one folder (depending on whether it exists already) and copies about 11 files. It makes no changes to the registry.

THE BASICS
The Test should require very little configuration to get it running. Once installed you can simply run the script either clicking on the "run script" icon on the toolbar or selecting "run script" from the "Automation" menu and selecting the file "MP3 Player Quick Test.dss". Running this file will open the load the right dScope configuration, open the spreadsheet, import the limits, and then wait for you to play a test signal from your device under test with an interface that looks like the below.

Connect the analogue outputs from the device to the dScope's analogue inputs, using the adaptors provided if appropriate, then play the test file. If the signal coming from the device is loud enough, the dScope will detect it and the tests will start automatically. If nothing happens, most likely this is because the level is too low. The default detection level is 0.2V. You can change it by clicking on the "Set Detection Level" button and entering a new value. Once the signal is detected, the test will proceed to make the measurements. A short time later, all being well, you will see a "Pass" screen as shown below.

After saving the results, the test will reset and is ready for another unit.

Resource Type: Scripts and Automation (File Download)
Download Link (https:): mp3_player_test_scripts.zip
Size: 1.9 MiB
Date 2009-03-27

Relevant Products:

	dScope Series IIIA+ Analogue-Plus Audio Test System
	dScope Series III Analogue & Digital Audio Test System