Digital Speech Processing
Host Laboratory Functions
A Host Laboratory provides all the functionality required to conduct a multi-coder testing effort for selection, characterization or qualification. The host lab provides an unbiased and consistent source of all processing steps required to create testing material for all subjective and objective test methods.
Input material is gathered from multiple sources and pre-processed for input to candidate and reference coders. Pre-processing may include noise mixing, filtering, gain adjustment, and concatenation.
The Host Lab is the central custodian of the coders under test as well as the reference processing systems. Proponents supply test vectors and it is the Host Lab's responsibility to insure all systems function as intended.
The preprocessed material is input to the coders under test as well standard reference coders and other reference system processors such as the Modulated Noise Reference Unit (MNRU). Within a complete test are often channel simulations. This requires the host lab to introduce errors to the bitstream between the analyzer and synthesizer modules of the given coders.
The system output is then post processed. These procedures often include splitting of concatenated files, further filtering and gain adjustment. Post processed files also need to be properly named to indicate the unique condition and stimuli.
A Host Lab must always establish procedures to insure all processing steps are performed correctly and maintain an audit trail. In large efforts, often two Host Labs will be used. In this case the processing duties are split and in addition a small representative subset of the other Lab's material is processed in order to perform a crosscheck.
ARCON has provided Host Laboratory functionality to the Department of Defense, the International Telecommunications Union, the European Telecommunications Standards Institute, the Association of Public Safety Officers under the auspices of the Telecommunications Industry Associations and others.