WILLTEK 4400 Mobile Phone Tester Series, Руководство пользователя

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Chapter 6 Tools
Audio measurements
4460 GSM System Option and 4468 EDGE System Option Version 12.20
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As detailed below, the 4400 provides several interfaces to connect to the mobile
phone. But where do I find the appropriate connector on the mobile?
There are no standardized audio connectors on the mobile phones; each manu-
facturer provides proprietary connectors. These can be found typically on the car
kit interface or on a test adapter. Please refer to the manufacturer for more
details.
Access to the audio menus There is access to the audio menus in two ways:
– For tests in asynchronous mode, push the T
OOLS
function key from the
Welcome menu. If the audio option is installed, the tool bar provides access
to the audio menus with a push on the [Audio] marker tab.
– For tests on a voice channel, select the appropriate system option and then
push the
|Calls & Meas.|
softkey from the Welcome menu. Now, origi-
nate a call (either from the mobile under test or from the base station).
When the call is active, push the
T
OOLS
function key. If the audio option is
installed, the tool bar provides access to the audio menus with a push on the
[Audio] marker tab.
Codec A voice codec is used to transform an audio signal into a bit stream that is then
transmitted over the RF channel. There are two optional codecs available.
Instead of measuring an analog signal from the AF input or AUX in input, the
digital audio signal transmitted over the RF traffic channel can also be analyzed.
The voice coded option is required to translate the binary coded information into
an 8 kHz sampled digital signal.
To the same token, the audio signal generated by the 4400 can be applied to the
traffic channel via the optional voice codec. The RF signal can then be used to
stimulate the AF parts of the mobile under test.
The codec algorithm itself (on the user interface of the 4400 often referred to as
TCH Type) can be selected from all GSM test menus before the call is set up.
Important to note
– When no codec option is installed on the 4400, the appropriate codec algo-
rithm is not available and the AF analyzer/generator will not work in the
mode explained above, although it is possible to select
FullRate
or
Enh.FullRate
on all GSM test menus.
– In asynchronous mode, the
Codec out
or
Codec in
settings are not
available on the corresponding menus, since the use of the codecs requires a
traffic channel to be set up.
– It is not possible to change the codec algorithm during an ongoing call.