Audio Precision Adds STI Measurement to APx500

Enables design validation of public address, flight recorder and public safety communication systems
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BEAVERTON, Ore.�Audio Precision has announced the recent addition of its Speech Transmission Index plug-in for the APx500 audio test software. Designed for engineers working on public safety communications and public address systems, the APx STI plug-in provides measurement capabilities conforming to international standard IEC 60268-16.

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STI is an objective measure that provides a single rating between zero and one that predicts the likelihood of syllables, words and sentences being comprehended in the intended medium. The rating is then broken down into qualification bands that range from bad (0-0.36) to excellent (0.75-1).

APx STI employs the most commonly used of the four direct measurement methods detailed by IEC 60268-16, Speech Transmission Index for Public Address. STIPA uses 14 modulation frequencies across seven octave bands, with two frequencies combined in each band, and all band-frequency combinations contained in a single signal. Total measurement time takes about 10-20 seconds.

After verifying the STI performance of designs with AP�s instrumentation, developers can us APx STI to test other audio and electro-acoustic test requirements. Once the plug-in is installed, the STIPA measurement can be incorporated into any measurement sequence.

The APx STI plug-in is available for a starting price of $500 and is compatible with all APx500 series analyzers.


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