SN EN 60118-4 : 1998 AMD 1 1998
Current
The latest, up-to-date edition.
HEARING AIDS - PART 4: MAGNETIC FIELD STRENGTH IN AUDIO-FREQUENCY INDUCTION LOOPS FOR HEARING AID PURPOSES
12-01-2013
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Suitability of the site for the installation of an
audio-frequency induction-loop system
4.1 General
4.2 Measurement of magnetic background noise level
5 Test signals
5.1 General
5.2 Speech signals
5.3 Pink noise signal
5.4 Sinusoidal signal
6 Characteristics to be specified, methods of measurement
and requirements
6.1 General
6.2 Amplitude characteristic of the system
(or amplifier)
6.3 Magnetic field strength
6.4 Setting up (commissioning) the system
6.5 Magnetic noise level due to the system
6.6 Frequency response of the magnetic field
6.7 Useful magnetic field volume
Annex A (informative) Small area systems
Annex B (informative) Measuring equipment
Annex C (informative) Provision of information
Annex D (informative) Measuring speech signals
Annex E (informative) Basic theory and practice of
audio-frequency induction-loop systems
Annex F (informative) Calibration of field-strength
meters
Bibliography
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