Last updated: September 29, 2009
This section is only applicable to the lab applications and the test application with a required feature license.
Digital Audio Interface (DAI) is a special interface to offer a platform that complete the conformance of speech codec test and the SLR/RLR (Sending/Receiving Loudness Rating) performance test of the analogue and acoustic devices. Through DAI, you can insert and extract speech data in both the transmit and receive directions. Note that only the speech coder/decoder test is discussed in this section.
See 3GPP TS 44.014 for more information about Digital Audio Interface information.
The following figure shows the location of Digital Audio Interface in the Mobile Station. You can test the codec implementation of the Mobile Station based on a number of digital audio files sending or receiving through the Digital Audio Interface.
The interface provides the data exchange of 13 bit linear PCM at 8000 samples per second. In order to keep the pin count low, the data are transferred on a duplex set of serial lines at 104 kbits/s.
DAI test process are displayed as the following steps:
The figure below shows the timing of the Digital Audio Interface:
The following diagram shows a typical Digital Audio Interface test system configuration.
The Digital Audio Interface (DAI) typical test system is made up of Custom Test Station, GSM Mobile Station, 8960 Test set. The Customer Test Station connects with the Test Set via the GP-IB Interface and http Interface with Host Lan Cable. The Customer Test Station connects with the Mobile Station via Digital Audio Interface with suitable LAN Cable. The Test set connects with the Mobile Station via RF Interface.
The Customer Test Station acts as the control center of the DAI test system. The Customer Test Station can download/upload digital audio file into the test set using the 8960 DAI File Manager software, start the DAI Test, command the test set to start/stop playing or recording the digital audio files, and query the play or record status of the digital audio file by sending GPIB command to the test set.
The Customer Test Station or Controller releases reset pulse to command the Mobile Station to start test by issuing clock pulses when data transfer. The DAI doesn't have access to send the reset pulse.
The figure below shows the detailed view of the Digital Audio Interface test path. The test file is associate with codecs which can be Full Rate Speech (FS), Enhanced Full Rate Speech (EFS) and Half Rate Speech (HS), Adaptive Full Rate Speech (AFS), Adaptive Half Rate Speech (AHS) and Wideband Adaptive Full Rate Speech (WFS).
You can Test the Speech Decoder by performing the Digital Audio Interface (DAI) Downlink Test steps and the Speech Encoder by performing the Digital Audio Interface (DAI) Uplink Test steps .
DAI Downlink Test is used to test the performance of the Speech Decoder in the Mobile Station. To perform a downlink test, You should follow the following steps:
Note, the DAI File Manager is an unofficial tool provided by Agilent, which helps you to upload/download the DAI files to/from the test set. You can launch the DAI File Manager from the following webpage:
url: http://wireless.agilent.com/rfcomms/dloads/swdownloads.aspx?pageid=45
See How to play the Digital Audio Interface (DAI) File for instructions on how to play the COD/DEC file and upload the digital audio file via the test set.
See Programming a Downlink DAI Test for instructions on how to program a automatic DAI Downlink Test.
DAI Uplink Test is used to test the performance of the Speech Encoder in the Mobile Station.To perform a uplink test, You should follow the following steps:
See How to record the Digital Audio Interface (DAI) File for instructions on how to record the COD/DEC file and download the digital audio file via the test set.
See Programming a Uplink DAI Test for instructions on how to program a automatic DAI Uplink Test.
The following measurements shall be shut down for the duration of the play/record operation.
This parameter allows you to select which component in the mobile station is to be tested (Speech Encoder, Speech Decoder, or Acoustic), or just command the mobile station to work in normal state by setting the DAI to `Off'. The DAI Test Interface setting is stateless. Selecting the DAI Test Interface will result in the Layer 3 Test_Interface command being sent to the MS.
If an attempt is made to select Speech Decoder, Speech Encoder or Acoustic while the Operating Mode is not active cell an error message is generated: "
Cell operation rejected; Protocol request ignored
."
The GPIB command to set this parameter is CALL:TCHannel:DAINterface:TINTerface .
This parameter is used to start playing the COD/DEC reference file in the test set.
The following conditions are checked if you attempt to start playing a COD/DEC file. If one of these conditions is not met, an error message is generated:
The GPIB command to set this parameter is CALL:DAINterface:PLAY:STARt .
This parameter is used to stop playing the COD/DEC reference file in the test set.
The GPIB command to set this parameter is CALL:DAINterface:PLAY:STOP .
The GPIB command to set this parameter is CALL:DAINterface:PLAY:STATus .
This parameter is used to start recording the COD file in the test set.
The following conditions are checked if you attempt to start recording a COD/DEC file. If one of these conditions is not met, an error message is generated:
In addition to the above conditions, an error message is generated on the following conditions:
The GPIB command to set this parameter is CALL:DAINterface:RECord:STARt .
This parameter is used to stop recording the COD file in the test set.
The GPIB command to set this parameter is CALL:DAINterface:RECord:STOP .
This parameter queries the Recording Status of the COD file.
The GPIB command to set this parameter is CALL:DAINterface:RECord:STATus .
The Playing Progress indicates how far through playing the uploaded COD/DEC reference file the test set is.
The Recording Progress indicates how far through the maximum possible capture COD file the test set is.
The Playing / Recording Progress indicators are displayed on the front panel and updated frequently.
The Digital Audio Interface test is only available in active cell operating mode. If the 'Operating Mode' is changed to anything other than 'Active Cell', any active playing or recording of COD/DEC files is stopped.
On either full or partial preset the following actions are taken
The DAI Test also applies to the Dual Transfer Mode, You can perform the test on the voice call portion of the DTM connection.
Logging Digital Audio Interface (DAI) Messages
How to use the Digital Audio Interface Features