Audio Generator and Analyzer (with Option CMU-B41) CMU
1100.4903.12 6.64 E-10
Audio Generator and Analyzer (with Option CMU-B41)
Audio measurements form a separate function group (Non Signalling mode) with associated secondary
address. The Signalling mode is not available for audio measurements. However, it is possible to per-
form audio measurements while using the signalling modes from other function groups (e.g. establish a
call to a mobile in function group GSM900-MS Signalling and switch over to perform additional audio
measurements). Consequently, additional audio-related commands may be provided in other contexts
(for example, see the ROUTe:SPENcoder... and ROUTe:SPDecoder... commands in the GSM-MS
and other function groups).
The audio function group provides two independent measurements:
• In a single-tone audio measurement, the CMU generates an audio signal at constant level and fre-
quency (see section AF Generator (AFGenerator on p. 6.73 ff.) and analyzes a single-tone audio
input signal (see section Audio Analyzer (AFANalyzer) on p. 6.68 ff.).
• In a multitone measurement (see section Multitone Measurements (MULTitone on p. 6.75 ff.), the
CMU generates a composite audio signal consisting of up to 20 distinct test tones and analyzes an
audio input signal containing the same tones.
Note: The single-tone generator and the multitone audio measurement must not be running si-
multaneously. In manual control, this is ensured because the single-tone audio generator is
automatically switched off upon swichover to the Multitone menu and vice versa. In remote
control, the conflict must be resolved explicitly:
• The single tone AF generator must be switched off before a multitone measurement is
started.
• A running multitone measurement must be aborted before the single tone AF generator
is switched on.
In the case of two conflicting audio measurements, the READ..., FETCh..., SAM-
Ple... commands will result in an error message.
Two independent audio circuits are provided for both single tone and multitone measurements:
• In the primary audio circuit (subsystems AFANalyzer[:PRIMary] and AFGenera-
tor[:PRIMary] for single tone measurements, MULTitone:AF1Channel for multitone meas-
urements), the audio signals are applied to the connectors AF OUT (output, AF generator signal)
and AF IN (input) on the CMU front panel. The [:PRIMary] single tone audio circuit corresponds
to the Audio Analyzer/Generator menu and the associated configuration menu. The MULTi-
tone:AF1Channel audio circuit corresponds to the AF Chan. One multitone application.
• In the secondary audio circuit (subsystems AFANalyzer:SECondary and AFGenera-
tor:SECondary for single tone measurements, MULTitone:AF2Channel for multitone meas-
urements), the audio signals are applied to the connectors AUX 2 (output, AF generator signal) and
AUX 1 (input) on the CMU front panel. The :SECondary single tone audio circuit can not be con-
trolled manually. The MULTitone:AF2Channel audio circuit corresponds to the AF Chan. Two
multitone application.
With the exception of the input and output connectors, the two audio circuits are identical. Configura-
tions such as the input path (AFLevel) can be set independently. All remote control commands are
analogous.
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