Cochlear SPrint Sound Processor Informações Técnicas descarregar pdf (Página 18)

SECTION ONE | CLINICAL GUIDANCE

• IIDR (Instantaneous Input Dynamic Range) – is the selected range

of input signal at any instant in time that will be mapped between

T- and C-level, i.e. the audible range of sounds for a recipient. It is

a programmable value determined (in Freedom and CP810 sound

processors) by two MAP parameters, T-SPL and C-SPL. It is the dB

difference between the two. For example, at the default microphone

sensitivity of 12, for a T-SPL of 25 and C-SPL of 65, the IIDR is 65 - 25 =

40 dB.

• IDR (Input Dynamic Range) – is the entire operating range of the sound

processor including the AGC compression range. In contrast to the IIDR,

it is a ﬁxed value. It can be up to 75 dB for the Freedom and CP810 sound

processors.

• Q-value – controls the steepness of the amplitude growth function and

determines the percentage of a recipient’s electrical output dynamic range

that is allocated to the top 10 dB of the sound processor’s input dynamic

range. A low Q-value makes the loudness growth function steeper and has

the effect of making soft sounds perceptually louder (see Figure 2 below).

Figure 2 : Loudness

growth functions:

Base Level = 4,

Q varies

1 2 ... 13 14 15 16 17 18 19 20 21 22 23 ... 77 78

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