ESAT Forouzan - Chapter 3: Signals

Question 1

Before data can be transmitted, they must be transformed to _____________.
a. Periodic signals
b. Electromagnetic signals
c. Aperiodic signals
d. Low-frequency sine waves

Answer 1

b. Electromagnetic signals

Question 2

A periodic signal completes one cycle in 0.001 seconds. What is the frequency?
a. 1 Hz
b. 100 Hz
c. 1 kHz
d. 1 MHz

Answer 2

c. 1 kHz

Question 3

Which of the following can be determined from a frequency-domain graph of a signal?
a. Frequency
b. Phase
c. Power
d. All of the above

Answer 3

a. Frequency

Question 4

Which of the following can be determined from a frequency-domain graph of a signal?
a. Bandwidth
b. Phase
c. Power
d. All of the above

Answer 4

a. Bandwidth

Question 5

In a frequency-domain plot, the vertical axis measures the _____________.
a. Peak amplitude
b. Frequency
c. Phase
d. Slope

Answer 5

a. Peak amplitude

Question 6

In a frequency-domain plot, the horizontal axis measures the _____________.
a. Peak amplitude
b. Frequency
c. Phase
d. Slope

Answer 6

b. Frequency

Question 7

In a time-domain plot, the vertical axis is a measure of _______________.
a. Amplitude
b. Frequency
c. Phase
d. Time

Answer 7

a. Amplitude

Question 8

In a time-domain plot, the horizontal axis is a measure of _______________.
a. Signal amplitude
b. Frequency
c. Phase
d. Time

Answer 8

d. Time

Question 9

If the bandwidth of a signal is 5 kHz and the lowest frequency is 52 kHz, what is the highest frequency?
a. 5 kHz
b. 10 kHz
c. 47 kHz
d. 57 kHz

Answer 9

d. 57 kHz

Question 10

What is the bandwidth of a signal that ranges from 40 kHz to 4 MHz?
a. 36 MHz
b. 360 kHz
c. 3.96 MHz
d. 396 kHz

Answer 10

c. 3.96 MHz

Question 11

When one of the components of a signal has a frequency of zero, the average amplitude of the signal ____________.
a. Is greater than zero
b. Is less than zero
c. Is zero
d. A or B

Answer 11

d. A or B

Question 12

A periodic signal can always be decomposed into ______________.
a. Exactly an odd number of sine waves
b. A set of sine waves
c. A set of sine waves, one of which must have a phase of 0o
d. None of the above

Answer 12

b. A set of sine waves

Question 13

As frequency increase, the period ____________.
a. Decreases
b. Increases
c. Remains the same
d. Doubles

Answer 13

a. Decreases

Question 14

Given two sine waves A and B, if the frequency of A is twice that of B, then the period of B is ______________ that of A.
a. One-half
b. Twice
c. The same as
d. Indeterminate from

Answer 14

b. Twice

Question 15

A sine wave is _______________.
a. Periodic and continuous
b. Aperiodic and continuous
c. Periodic and discrete
d. Aperiodic and discrete

Answer 15

a. Periodic and continuous

Question 16

If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ____________ V.
a. 2
b. 1
c. -2
d. Between -2 and 2

Answer 16

c. -2

Question 17

A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means _______________.
a. P2 is zero
b. P2 equals P1
c. P2 is much larger than P1
d. P2 is much smaller than P1

Answer 17

b. P2 equals P1

Question 18

_______________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium.
a. Attenuation
b. Distortion
c. Noise
d. Decibel

Answer 18

a. Attenuation

Question 19

_______________ is a type of transmission impairment in which the signal loses strength due to the different propagation speeds of each frequency that makes up the signal.
a. Attenuation
b. Distortion
c. Noise
d. Decibel

Answer 19

b. Distortion

Question 20

______________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal.
a. Attenuation
b. Distortion
c. Noise
d. Decibel

Answer 20

c. Noise

Question 21

The ____________ has units of meters/second or kilometers/second.
a. Throughput
b. Propagation speed
c. Propagation time
d. B or C

Answer 21

b. Propagation speed

Question 22

___________ has units of bits/second.
a. Throughput
b. Propagation speed
c. Propagation time
d. B or C

Answer 22

a. Throughput

Question 23

The ___________ has units of second.
a. Throughput
b. Propagation speed
c. Propagation time
d. B or C

Answer 23

c. Propagation time

Question 24

When propagation speed is multiplied by propagation time, we get the _____________.
a. Throughput
b. Wavelength of the signal
c. Distortion factor
d. Distance a signal or bit has traveled.

Answer 24

d. Distance a signal or bit has traveled.

Question 25

Propagation time is ____________ proportional to distance and ___________ proportional to propagation speed.
a. Inversely; directly
b. Directly; inversely
c. Inversely; inversely
d. Directly; directly

Answer 25

b. Directly; inversely

Question 26

Wavelength is __________ proportional to propagation speed and __________ proportional to period.
a. Inversely; directly
b. Directly; inversely
c. Inversely; inversely
d. Directly; directly

Answer 26

d. Directly; directly

Question 27

The wavelength of a signal depends on the ______________.
a. Frequencies of the signal
b. Medium
c. Phase of the signal
d. A and B

Answer 27

d. A and B

Question 28

The wavelength of green light in air is _________ the wavelength of green light in fiber-optic cable.
a. Less than
b. Greater than
c. Equal to
d. None of the above

Answer 28

a. Less than

Question 29

Using the Shannon formula to calculate the data rate for a given channel, if C = B, then __________.
a. The signal is less than the noise
b. The signal is greater than the noise
c. The signal is equal to the noise
d. Not enough information is given to answer the question

Answer 29

c. The signal is equal to the noise