Modern Electronic Communication by Gary Miller Chapter 11 with Answers

Chapter 11 Transmission Lines

1	The chief advantage of coaxial cable over open-wire line is
	a. Minimized radiation losses
	b. Low cost
	c. Low noise pick up
	d. Low resistive losses
2	Unshielded twisted-pair cable is
	a. Seldom used due to noise problems
	b. Increasingly used in computer networking
	c. More costly than coaxial cable
	d. All the above
3	The ratio of actual velocity to free-space velocity is called
	a. Velocity factor
	b. Relative dielectric constant
	c. Velocity of propagation
	d. Delay time
4	In a balanced line, the same current flows in each line but is
	a. 45º out of phase
	b. 90º out of phase
	c. 180º out of phase
	d. 270º out of phase
5	What is the length of a quarter-wavelength section of RG-8A/U coaxial cable at a frequency of 144.2 Mhz if its velocity factor is 0.69.
	a. 52.1 cm
	b. 35.9 cm
	c. 143.6 cm
	d. 2.08 m
6	A nonlossy transmission line that is terminated with a resistive load that is equal to the characteristic impedance of the line
	a. Has the same impedance at all points along the line
	b. Has a VSWR of 1:1
	c. Has the same voltage at points along the line
	d. Has a reflection coefficient at the load equal to zero
	e. All the above
7	A flat line indicates
	a. No reflection
	b. VSWR = 1
	c. No physical imperfections
	d. a and b
8	A nonlossy transmission line terminated with a short circuit has an
	a. In-phase reflected voltage that is equal in magnitude to the incident voltage
	b. Opposite-phase reflected voltage that is equal in magnitude to the incident voltage
	c. In-phase reflected voltage that is smaller in magnitude than the incident voltage
	d. Opposite-phase reflected voltage that is smaller in magnitude than the incident voltage
9	A manufacturer's specification dealing with crosstalk and attenuation is
	a. ACR
	b. CAS
	c. CAA
	d. AAC
10	A 50- transmission line that has a load impedance of 300 has a VSWR of
	a. 6:1
	b. 1:6
	c. 0.666:1
	d. 1.5:1
11	The input impedance of a quarter-wavelength section of a 50- transmission line that is terminated with a short is
	a. 50
	b. 0 (a short)
	c. Infinite (open)
	d. 100
12	A device that is used to match an unbalanced transmission line to a balanced transmission line is called a
	a. Quarter-wavelength matching transformer
	b. Balun
	c. Shorted-stub section
	d. Slotted line
13	A 50- transmission line with a 300- load impedance has a reflection coefficient of
	a. 6
	b. 0.166
	c. 0.714
	d. 1.4
14	A cable has an inductance of 1 nH/ft and capacitance of 1 nF/ft. The delay introduced by a 1-ft section is
	a. Not able to be calculated with the given information
	b.
	c.
	d.
15	A transmission line can be used as a(n)
	a. Inductor
	b. Capacitor
	c. Filter
	d. Matching section
	e. All the above

Answers:

A

B

A

C

B

E

D

B

A

A

C

B

C

B

E