Audio Precision has released a speech intelligibility measurement option for APx500 audio test software based upon the ABC-MRT speech processing algorithm.
Measuring speech intelligibility is an important capability for engineers designing and validating a wide range of communication systems, products and components, especially those related to public safety (police, fire, emergency) where intelligibility
– or comprehensibility – of the transmitted speech is critical. One of the more precise definitions of intelligibility is the proportion of speech items (words and/or speech sounds) uttered by a talker, and sent via a communication system, that can be recognised by the listener.
ABC-MRT (Articulation-Band Correlation Modified Rhyme Test) was developed by the Institute for Telecommunication Sciences (ITS) of the United States National Telecommunications & Information Administration (NTIA). It follows the paradigm of the Modified Rhyme Test, a technique for assessing speech intelligibility that involves subjective assessment by human subjects as detailed in ANSI/ASA Standard S3.2. To eliminate the time, complexity, and expense of the traditional human subject-based methodology, ABC-MRT uses a form of automatic speech recognition (ASR) to conduct an automated measurement that is closely correlated – greater than 95 per cent – to a Modified Rhyme Test. An added benefit of ABC-MRT is its use of real speech (English only), allowing it to support the testing of systems that use noise suppression and/or codecs that only pass speech.
Using the ABC-MRT option allows developers to measure the speech intelligibility of their designs with AP’s industry-leading instrumentation and use that same equipment for the rest of their audio and electro-acoustic test requirements. Once installed, the ABC-MRT measurement can be easily incorporated into any test sequence.
‘For designers and developers needing perceptual audio test capabilities, whether measuring quality or intelligibility, AP offers a wide range of options,’ said Dave Schmoldt, Audio Precision CEO. ‘From PESQ and POLQA quality measurements to STI, and now ABC-MRT, intelligibility measurements, APx can meet their needs for analog, digital, electro-acoustic and perceptual audio test.’
The ABC-MRT software option (APX-SW-ABC-MRT) is available now, and retails at US$2,100. It requires APx500 audio measurement software release v4.5.2 (or later) and is compatible with all analysers in the APx500 Series.
More: www.ap.com