| Zugriffsnummer | 25092 |
| Dokumenttyp | Konferenzartikel |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Specification and calibration of acoustic short-term stimuli for objective audiometry |
| Autor(in); Institution |
Fedtke, Thomas; 1.6, Schall, PTB-Braunschweig
Hensel, Johannes; 1.6, Schall, PTB-Braunschweig
|
| Quelle/Jahr | Proceedings ICA 2010, 20th International Congress on Acoustics:(2010), 5 S. |
| Availability | [CD-ROM] ; file name: p534.pdf |
| Herausgeber(in) |
Burgess, Marion
|
| ISBN | 978-0-646-54052-8 |
| Verlag | Sydney: Australian Acoustical Society, NSW Division |
| Konferenzangaben | 20 th International Congress on Acoustics, Sydney, 23-27, August, 2010, Australia |
| Klassifikationscode | PACS: 43.58.+z ; PACS: 43.64.+r ; PACS: 43.66.+y ; PACS: 43.80.+p |
| Zusammenfassung | Many applications in objective audiometry measure and evaluate responses of the hearing system to acoustic short-term stimuli. One of the earliest and best known among those signals of short duration is the 'reference pulse' specified in the standard IEC 60645-3. This definition of an electrical reference signal dates back to times when audiometric equipment essentially consisted of analogue components used in laboratory set-ups. Therefore, overshoot caused by the limited bandwidth of the electrical signal was not considered in this definition. Recent equipment, however, often uses audio-frequency DA converters which imply a limited bandwidth of the signal path. Even if their sample rate is chosen in a way that the physiological and psychoacoustic effects of the pulse do not differ from those of the quasi-non-band-limited pulse, the transients caused by DA conversion and bandwidth limitation lead to the fact that the time response of the pulse does not comply with the current IEC specification. In order to resolve this problem a modified definition of the reference pulse by detailed time-domain tolerance diagrams is discussed. Meanwhile, in addition to the "signals of short duration" specified in IEC 60645-3, a variety of short-term stimuli with considerably different temporal characteristics is available for audiometry. ISO 389-9 explicitly allows the application of those signals, provided that they are clearly specified by the manufacturer. The concept of expressing their reference thresholds by means of peak-to-peak Equivalent Reference Equivalent Threshold Sound Pressure Levels (peRETSPLs) is easy to implement, even with rather simple instrumentation. However, this concept results, for some stimuli, in calibration values which do not at all correlate with neither the behavioural hearing thresholds nor the spectral energy of the signals. Attempts for improving the calibration procedure with respect to these 'inconsistencies' are sketched out in this paper. |
