Digital Signal Processing Reference
In-Depth Information
"H i s to r y"
Time domain
FFT
Freq. domai n
DAC Output
1,25
Time domain
1,00
0,75
0,50
0,25
0,00
-0,25
-0,50
-0,75
H
H
i
i
iiii
iii
iiii
i
i
i
iis
s
s
ss
s
ss
s
s
s
sst
t
t
tt
t
o
o
o
oo
o
oo
o
o
or
r
r
r
r
r
ry
y
y
y
yy
y
yy
yy
y
yy
-1,00
0.25
0.50
0.75
1.00
s
Frequency domain
0,055
0,050
0,045
0,040
0,035
0,030
0,025
0,020
0,015
0,010
0,005
0,000
250
500
750
1000
1250
1500
1750
2000
2250
2500
Hz
Illustration 71:
The word "history" as a sequence of vowels and consonants
In the time domain vowels and consonants can be distinguished quite easily. The shape of the plosives
(consonants) are clearly recognisable.
The frequency domain of the complete word "history", however, does not provide any relevant information.
Again, a waterfall representation or frequency-time landscape as shown in Illustration 72 and Illustration
73 is needed.
But no matter what the details behind these processes are, one thing is certain, they are
biophysical processes, or to be more precise, phenomena from the field of the physics of
waves and oscillations. As nature is the great preceptor of natural sciences such as com-
munications engineering I should like to discuss briefly the principles of language
generation and perception.
