The Rem440 Test Signal Characteristics; Appendix 1 - Interacoustics Affinity 2.0 Additional Information

2.0
Affinity Additional Information

2.15 Appendix 1

2.16 The REM440 Test Signal Characteristics

Pure Tone frequency accuracy is ±1%. Crest factor is 3 dB.
Warble Tone frequency accuracy is ±1%, warble frequency 0100 Hz and intensity 010%, sine wave
frequency modulation. Crest factor 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 filter.
Pseudo random noise. Is a semi-broad-band noise produced from random noise weighted with a 2nd order
200 Hz high pass filter and a 1st order 900 Hz low pass filter as described in the ANSI S3.42 -1992 standard.
Crest factor is 10 dB.
Chirp. Is a linear frequency sweep from 100 to 10 kHz in 23 mS = one FFT measuring. The amplitude is
constant during the sweep. Crest factor = 3 dB.
Band limited white noise is a random noise signal band limited by 12 kHz 2. order low pass filter. Crest
factor 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
speak ers represent only one language and are therefore not internationally applicable. Therefore, the
European Hearing Instrument Manufacturing Association (EHIMA) has set up the ISMADHA work ing 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 filter or a 3 dB rise per octave
measured with an FFT.
ICRA Noise:
ICRA: urgnmn
Unmodulated random Gaussian noise - Male weighted - Normal effort - Level Ref. Crest factor = 13
dB.
ICRA: urgnmr
Unmodulated random Gaussian noise - Male weighted - Raised effort - Level Ref+5.7dB. Crest factor
= 14 dB.
ICRA: urgnml
Unmodulated random Gaussian noise - Male weighted - Loud effort - Level Ref+12.1 dB. Crest factor
= 14 dB.
ICRA: 3bsmnfn
3 Band speech modulated noise (3bSMN) - Female weighted - Normal effort - Level Ref. Crest factor
= 27 dB.
ICRA: 3bsmnmn
3 Band speech modulated noise (3bSMN) - Male weighted - Normal effort - Level Ref. Crest factor =
27 dB.
ICRA: 2pb1f1mn
2 persons babble, 1female 3bSMN + 1 male 2bSMN - Idealized - Normal effort - Level Ref + 3dB.
Crest factor = 24 dB.
ICRA: 6pbn
6 persons babble, 1f+1m+2f(-6db)+2m(-6dB), all 3bSMN - Idealized - Normal effort - Level Ref +
4.7dB. Crest factor = 23 dB.
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