HOST LABORATORY AND DATA INTERCHANGES

COMSAT Laboratories acted as the processing host laboratory for Phases 1 and 2 of the CCITT Study Group XV 16 kbit/s speech coder evaluation program. The host laboratory was responsible for all preparations nee ded to allow the participating organizations to conduct subjective spe ech quality tests on the floating point hardware version of the 16 kbi t/s LD-CELP coding algorithm. COMSAT was assisted by INTELSAT who prov ided funding, British Telecom and CPqD/Telebras (Brazilian Telecom Adm inistration) who supplied personnel 1 and by AT&T, Bellcore, National Institute of Science and Technology (NIST, a part of the US Department of Commerce), Nippon Telegraph & Telephone (NTT), and Philips Communi cation Industry AG (PKI) which supplied hardware/software. Additionall y, the host laboratory worked with 12 laboratories (see Table 1) which provided source speech material in 9 different languages and conducte d the subjective and objective tests. These efforts spanned the period between October 1989 and July 1990 for Phase 1 and from February to m id-April 1991 for Phase 2. The purpose of this paper is to describe th e host laboratory functions that COMSAT performed. We also describe th e Write Once and Read Many times (WORM) based data interchange system, defined by Bellcore and COMSAT, that was used to exchange data effici ently (a total of about 16,000 Mbytes) between participating laborator ies. Finally, we describe the Common Analog Interface, built by NTT, w hich was used to ensure that all tested codecs received equal treatmen t.