Chapter 6
Tools
Audio measurements
240
4460 GSM System Option and 4468 EDGE System Option
Version 12.20
Frequency —
Entry field to set the frequency of the audio generator.
Entry range: 20 Hz to 20 kHz in increments of 0.1 Hz.
Level (AF out) —
Entry field to set the RMS-valued output voltage of the AF
signal on the
“AF out”
connector.
Entry range: 0.0 V(rms) to 5.599 V(rms) in increments of 1 mV.
Signal Source —
This selection field allows to select the signal to be fed into the
AF basic analyzer.
Selections possible are:
AF in
,
AUX in
and
Codec out
.
AF in
means that the signal connected on the
“AF in”
socket will be analyzed,
while
AUX in
will analyze the signal connected to the
“AUX 4 (AUX in)”
connector.
Setting
Codec out
finally will forward the audio signal decoded by the 4400’s
internal codec to the AF basic analyzer.
AF analyzer – softkeys
The softkeys of the AF basic analyzer menu provide direct access to the following
functions:
NOTE
When using audio signals for transmission over the air interface, the audio
frequency should be set in a range between 300 to 3200 Hz as any voice
codec will only operate in this frequency range (just like a normal telephone
line, where the audio signal transmitted is also limited to this frequency
range).
NOTE
Codec out
cannot be selected unless a call setup has been performed.
NOTE
Codec out
cannot be AF analyzer source and signal destination at the same
time. If the selection field does not allow to select
Codec out
, first deselect
Codec in
as the signal destination of the
“Audio frequency generator”
.
Provides direct access to the Parameters menu of the AF basic
analyzer.
A push on this softkey stops the generation of audio signals
and terminates all audio outputs.
The softkey will change to
|START Gen.|
. Pushing this
softkey will switch on the audio generator again with all pre-
vious settings and all outputs will be on the same connectors
and levels as set before.
