HEARING AID COMPONENTS

2.1 BLOCK DIAGRAMS

2.2 MICROPHONES

2.2.1 Principle of operation

2.2.2 Frequency response of microphones

2.2.3 Microphone imperfections

2.2.4 Directional microphones

2.2.5 Microphone location

2.3 AMPLIFIERS

2.3.1 Amplifier technology

2.3.2 Peak clipping and distortion

2.3.3 Compression amplifiers

2.4 DIGITAL CIRCUITS

2.4.1 Analog to digital converters

2.4.2 Digital signal processors

2.4.3 Hard-wired digital processing
2.4.4 General arithmetic digital processing
2.4.5 Sequential processing, block processing, and hearing aid delay
2.4.6 Digital-to-analog converters
2.4.7 Specifications for digital hearing aids
2.4.8 Digital versus analog hearing aids

2.5 FILTERS, TONE CONTROLS AND FILTER STRUCTURES

2.5.1 Filters
2.5.1 Tone controls

2.5.2 Filter structures

2.6 RECEIVERS

2.6.1 Principle of operation

2.6.2 Frequency response of receivers

2.7 ACOUSTIC DAMPERS

 

2.8 TELECOILS

 

2.9 AUDIO (ELECTRICAL) INPUT

 

2.10 REMOTE CONTROLS

 

2.11 BONE CONDUCTORS

 

2.12 BATTERIES

2.12.1 Principle of operation

2.12.2 Operating voltage

2.12.3 Capacity and physical size
2.12.3 Rechargeable batteries

2.13 CONCLUDING COMMENTS