Zoom out Search Issue

IEEE SIGNAL PROCESSING MAGAZINE [74] MARCH 2015

spectral shape without explicitly estimating speech features.

Indeed, there is no inherent assumption that the sound signals

processed for CI recipients contain any speech.

ACE has many signal processing modules in common with CIS

and almost all other current CI processing schemes (blocks 1–6 in

Figure 2). However, the major distinction with CIS is that on each

stimulation cycle, only a subset of the available electrodes is

selected. This is indicated by the “channel selection” block

(block 7) in Figure 2. The subset comprises the n type of process-

ing scheme is sometimes referred to as n-of-m. In cochlear CI sys-

tems, typically eight electrodes from the available set of 22 are

selected for stimulation at a rate of 900 pps per electrode, although

stimulation parameter values can be varied to optimize perfor-

mance for individual recipients.

–1

6,400

3,200

Frequency (Hz)Magnitude + Electrode

1,600

800

400

200

100

Relative Magnitude

Frequency (Hz)Magnitude + Electrode Relative Magnitude

–2

0.2 0.3 0.4 0.5 0.2 0.3 0.4 0.5 0.2 0.3 0.4 0.5

Waveform MP3000 EE

ACESpectrogram F0mod

HiRes120CIS-22ch FSP

Time (s) Time (s) Time (s)

(g) (h) (i)

(d) (e) (f)

(a) (b) (c)

“A Boy Fell from the Window”—Zoomed in on “Boy”

boy fell

[FIG5] (a) Waveform, (d) spectrogram, and (b)–(c) and (e)–(i) electrodograms of the sentence ”A boy fell from the window” from the

HINT corpus, uttered by a male speaker, but zoomed in on the word ”boy.”

THE WORLD’S NEWSSTAND

THE WORLD’S NEWSSTAND