The Rem440 Test Signal Characteristics - Interacoustics Affinity 2.0 Additional Information

2.18 Appendix 1

2.19 The REM440 test signal characteristics

Pure Tone f requency accuracy is ±1%. Crest f actor is 3 dB.
Warble Tone f requency accuracy is ±1%, warble f requency 0100 Hz and intensity 010%, sine wave
f requency modulation. Crest f actor is 3 dB.
Random Noise is a noise with a linear spectrum measured with an FFT or a 3 dB drop per octave measured
with a 1/3 octave f ilter.
Pseudo random noise. Is a semi-broad-band noise produced f rom random noise weighted with a 2nd order
200 Hz high pass f ilter and a 1st order 900 Hz low pass f ilter as described in the ANSI S3.42 -1992 standard.
Crest f actor is 10 dB.
Chirp. Is a linear f requency sweep f rom 100 to 10 kHz in 23 mS = one FFT measuring. The amplitude is
constant during the sweep. Crest f actor = 3 dB.
Band limited white noise is a random noise signal band limited by 12 kHz 2. order low pass f ilter. Crest
f actor is 9 dB.
ISTS is "for analyzing the processing of speech by a hearing aid, a standard test signal is necessary which
allows for reproducible measurement conditions, and which features all or most relevant properties of natural
speech. Those properties are e.g., the modulation spectrum and the fundamental frequency as well as its
harmonics. Existing artificial signals fulfill these requirements inadequately and recordings from natural
speakers represent only one language and are therefore not internationally applicable. Therefore, the
European Hearing Instrument Manufacturing Association (EHIMA) has set up the ISMADHA working group
and has initiated this project resulting in an International Speech Test Signal (ISTS). The ISTS is based on
natural recordings but is largely non-intelligible because of segmentation and remixing. The intention is to
include this test signal with a new measurement method for a new hearing aid standard" (Holube et al.
2006).
PinkNoise is a noise with a linear spectrum measured with a 1/3 octave f ilter or a 3 dB rise per octave
measured with an FFT.
/SS/ is a shaped IF Noise to emphasize the high f requencies. It was developed by the team at University
Western Ontario (UWO) who are also responsible f or the DSLmi/o f itting algorithm.
/SH/ is a shaped IF Noise to emphasize the high f requencies, it contains some lower f requencies compared
to the /ss/ stimuli above. It was developed by the team at University Western Ontario (UWO) who are also
responsible f or the DSLmi/o f itting algorithm.
Both the /ss/ and /sh/ stimuli are used f or verif ication of frequency lowering/shif ting technologies f ound in
modern hearing aids.
ICRA Noise:
ICRA: urgnmn
Unmodulated random Gaussian noise - Male weighted - Normal ef f ort - Level Ref . Crest f actor = 13
dB.
ICRA: urgnmr
Unmodulated random Gaussian noise - Male weighted - Raised ef f ort - Level Ref +5.7dB. Crest f actor
= 14 dB.
ICRA: urgnml
Unmodulated random Gaussian noise - Male weighted - Loud ef f ort - Level Ref +12.1 dB. Crest f actor
= 14 dB.
ICRA: 3bsmnfn
3 Band speech modulated noise (3bSMN) - Female weighted - Normal ef f ort - Level Ref . Crest f actor
= 27 dB.
D-0004576-Q – 2022/05
Affinity/Equinox2.0 – Additional Information
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