Hands free at Brüel & Kjær
Worldwide sales of mobile phones reached 132.8 million units in the third quarter of 2003, an increase of 21% over the same period in 2002, according to US research firm Gartner, who believe the total for 2003 could reach half a billion units, up from 284 million in 1999. Not surprisingly, competition between mobile-phone providers is intense and the consumer has become a discerning listener, using the quality of sound, for example voice intelligibility or ring tone attractiveness, as purchase criteria.
Designing and manufacturing high quality mobile phone handsets is not the only aim of the telecom industry. With the latest generation of mobiles featuring high-speed multimedia, mobile internet and audio and video streaming, higher-quality acoustics are also a key issue. In addition, the introduction of legislation in many countries banning the use of hand-held mobile phones whilst driving has meant that the acoustic quality of the devices currently available for hands-free solutions is paramount. Brüel & Kjær's Pulse™ analyser is being used to determine the acoustic performance of mobile phones with a hands-free function. Measurements are performed using a free-field microphone with a mouth simulator or head and torso simulator as shown in the illustration. These measure the full receive and transmit signal paths, giving realistic measurements of phone performance.