DAGA 2010 - Deutsche Gesellschaft für Akustik eV

Programm DAGA 2010 95
Di. 17:00 Bauwesen H1 Sprache im Kraftfahrzeug
Wideband in Car Hands-Free
H.W. Gierlich
HEAD acoustics GmbH
Wideband speech services in cars will be a great improvement compared
to narrowband speech services, especially for the driver inside the
car: Wideband speech reduces drivers’ distraction, increases the intelligibility
and reduces the perception of poor speech quality when switching
between audio presentation and speech communication. The support of
such services by the different networks and services also forms the basis
for the integration of wideband speech hands-free services in cars. However,
to achieve a superior speech quality inside the car all elements
involved in the transmission have to provide adequate speech quality.
This includes the Bluetooth link used to connect the hands-free car system
via the mobile terminal, the mobile terminal and the IP-based fixed
network as well. The presentation will give an overview about the state
of the art of the connections used today and their impact on speech
quality. Relevant measurements for the qualification and optimization of
wideband car hands-free systems are introduced and their relevance for
the different parameters contributing to the speech quality are discussed
based on the new ITU-T Focus Group CarCom specification.
Di. 17:25 Bauwesen H1 Sprache im Kraftfahrzeug
Echo Assessment in Narrowband and Wideband Scenarios
F. Kettler und M. Lepage
HEAD acoustics GmbH
Echo disturbances are typically characterized by the two parameters
echo attenuation and echo delay (round trip delay). Both values are verified
individually with reference to common standards in telecommunications.
A new approach to quantify echo disturbances was intro-duced
during the last NAG/DAGA 2009. It is based on a hearing adequate echo
analysis and considers the masking by the user’s own voice. Furthermore
it is applicable for narrowband and wideband scenarios, which makes
it suitable for upcoming telecommunication networks and the new generation
of terminals. Results of subjective tests, both talking and listening
tests and listening only tests as well as latest modifications on the echo
assessment model are discussed.