Biomedical Engineering Reference
In-Depth Information
3.
Describe the biosignal that the electrical activity of a normal heart would generate during a
bicycle race.
4.
A 16-bit A/D converter is used to convert an analog biosignal with a minimum voltage of
-30 mV and a maximum voltage of 90 mV. What is the sensitivity?
5.
An EMG recording of skeletal muscle activity has been sampled at 200-250 Hz and correctly
digitized. What is the highest frequency of interest in the original EMG signal?
6.
Two signals,
x
1
(
t
) and
x
2
(
t
), have the magnitude spectrum shown in Figure 11.41. Find the
Nyquist rate for:
(a)
x
1
(
t
)
(b)
x
2
(
t
)
x
ð
t
Þ¼
x
1
ð
t
Þ
*
x
2
ð
t
Þ
(Hint: Apply the convolution theorem.)
(c)
X
2
(
)
X
1
(
ω
)
ω
ω
ω
0
3000
π
0
5000
π
FIGURE 11.41
7.
Consider the signal
x
ð
t
Þ¼
3
þ
sin
ð
2p 100
t
Þþ
cos
ð
2p 250
t
þ p=
3
Þ
Find the Nyquist frequency.
8.
A sinusoid with the frequency of 125 kHz is sampled at 70,000 samples per second. What is
the apparent frequency of the sampled signal?
9.
An electroencephalographic (EEG) signal has a maximum frequency of 300 Hz. The signal is
sampled and quantized into a binary sequence by an A/D converter.
(a)
Determine the sampling rate if the signal is sampled at a rate 50 percent higher than the
Nyquist rate.
(b)
The samples are quantized into 2,048 levels. How many binary bits are required for each
sample?
10.
Find the exponential Fourier series for the signal shown in Figure 11.42a.
11.
Find the exponential Fourier series for the signal shown in Figure 11.42b.
12.
) is a periodic signal shown in Figure 11.43. Find its trigonometric Fourier series.
13.
Consider the following trigonometric Fourier series:
f
(
t
:
e
j
4
t
þ
e
j
4
t
2
f
ð
t
Þ¼
3
þ
3 cos
ð
t
Þþ
2 cos
ð
2
t
Þþ
4 sin
ð
2
t
Þ
4
) in its compact trigonometric Fourier series form.
14.
Explain why the exponential Fourier series requires negative frequencies.
Write
f
(
t
