Biomedical Engineering Reference
In-Depth Information
(e)
(a)
Microphone array
+
W
W
12
+
N
+
Synaptic
weights
W
21
N
N
(b)
(c)
(d)
Integrate fire neurons
1cm
FIGURE 2.10
A neuromorphic acoustic source localizer mimicking the sensory mechanism in the parasitoid fly
[11]
:
(a) architecture of the localizer interfacing with a microphone array, (b) micrograph of the localizer IC fabricated in a 0.5
μ
m
CMOS processor, (c) localizer system board integrating the microphone array and the localizer IC, (d) outputs from the
microphone array showing the differential amplification of the ITD when the input is a tone, and (e) output of the localizer
demonstrating a bearing estimation better than 2° resolution.
quadrant 90° >
θ
> 0°. Inserting Eq.
(2.23)
into
Eqs.
(2.25) and (2.26)
, we obtain the following
expressions:
Combining the two Eqs.
(2.28)
, we get
N
|
s
(1)
[
n
]|(sin θ +
W
11
[
n
] cos θ)
W
11
[
N
]=−ξ
n
=1
N
(
v
1
[
n
]−
v
1
[
n
− 1])sgn(
s
(1)
[
n
]).
N
+ ξ
d
1
[
n
]sgn(
s
(1)
[
n
]),
W
11
[
N
]=−ξ
n
=1
n
=1
(2.29)
(2.28)
d
1
[
n
]=
s
[
n
] sin θ +
W
11
[
n
]
s
(1)
[
n
] cos θ
− (
v
1
[
n
]−
v
1
[
n
− 1]).
Let
W
11
denote the converged value such that
W
11
[
n
]
n
→∞
−→
W
11
. Eq.
(2.29)
then leads to
