Tyco 579-769 specifications Emergency Voice/Alarm Communications Systems

Influences on Intelligibility	3-2
Introduction	3-2
Background Noise	3-3
Reverberation	3-4
Distortion	3-5
Microphone Technique	3-5
Measures of Intelligibility	3-6
Introduction	3-6
The Common Intelligibility Scale (CIS)	3-6
The STI Method	3-7
STIpa	3-7
STITEL	3-7
RASTI	3-7
Percent (%) ALcons	3-7
Phonetically Balanced Word Scores	3-7
Practical Measurement of Intelligibility	3-8
Introduction	3-8
Tools for Predicting Intelligibility	3-9
Introduction	3-9
Acoustical Modeling Software	3-9

Chapter 4 Emergency Voice/Alarm Communications Systems	4-1
Introduction	4-1
In this Chapter	4-1
A Typical Emergency Voice/Alarm Communications System	4-2
Parts of an Emergency Voice/Alarm Communications System	4-3
Command Center	4-3
Audio Riser	4-3
Transponder	4-3
Speaker Circuits	4-4

Chapter 5 Regulatory Issues	5-1
Introduction	5-1
In this Chapter	5-1
Audibility	5-2
Tones and SPL	5-2
High Background Noise	5-3
Large Areas	5-3
Intelligibility	5-4
Intelligibility	5-4
Intelligibility Certification	5-5

Chapter 6 Speaker System Design Method	6-1
Introduction	6-1
In this Chapter	6-1
Speaker Design Method	6-2
Introduction	6-2

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