1. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 1 Copyright 2008 US EMC Standards Corporation HEI Study Joe Morrissey Motorola ANSI ASC C63® Subcommittee 8

2. Radio Circuitry Audio Receiver RF Source (Mobile Phone)RF Victim (Hearing Aid) Desired Signal RF Signal Carrier Frequency Burst Structure Modulation Dynamic Signal Field Polarization E- and H- components Audio Band Noise oscillators clocks Handset / Antenna Type / Location Radiation Pattern Distance (Near Field) Transmit Power Other Noise Receiver Wires (Length / E-Field) Loops (Area / H-Field) Shielding by head Demodulator Square Law

3. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 3 Copyright 2008 US EMC Standards Corporation Hearing Aid Anatomy Receiver Microphone Battery Turnpot adjust Molded shell Plastic tube On / Off / TC switch Telecoil Integrated Circuit Wiring

4. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 4 Copyright 2008 US EMC Standards Corporation Captured Acoustic Products

5. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 5 Copyright 2008 US EMC Standards Corporation E- vs H- Field

6. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 6 Copyright 2008 US EMC Standards Corporation

7. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 7 Copyright 2008 US EMC Standards Corporation Wi-Fi Technology 802.11b (2.45 GHz) DSSS encoding format GFSK modulation 802.11a (5 GHz) OFDM encoding format PSK,QAM modulation 802.11g (2.45 GHz) DSSS / OFDM encoding format PSK / QAM modulation Frame Duration data rate data length Inter-Frame Spacing traffic signal quality 802.11g backwards compatible (b) higher data rate (a) Defined ParametersDynamic Parameters

8. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 8 Copyright 2008 US EMC Standards Corporation GSM Bursting Structure

9. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 9 Copyright 2008 US EMC Standards Corporation 217 Hz or 4.6 msec

10. October 2008 Measurement of Hearing Aid Compatibility Workshop, C63.19 (2007) Slide 10 Copyright 2008 US EMC Standards Corporation

11. Subjective Assessment

13. X2X2 X 0.5 4 msec TC 550 msec T.C. Peak DetectorRMS Level MeasurementSpectral Weighting Similar to CISPR, ITU-R 468 Quasi-Peak DetectionSimilar to A-weighting from square- law detector to DC meter The weighting function: The weighting function consists of straightforward spectral weighting followed by temporal weighting. Each step is clearly mathematically definable. Implementation may be in hardware or software.

14. 20.6 Hz12.2 kHz107.7 Hz 737.9 Hz 369 Hz 3 kHz, 2 nd order D.F. = 0.707 x 1.2589 x 1.0864 (A-weighted) The spectral weighting portion: from square- law detector (or conditioned baseband mag- netic probe for ABM2) x2 new-weighted