Electronic Communication by Gary Miller Chapter 17 with Answers

Chapter 17 Fiber Optics

1	Which is an advantage of optical communication links over using transmission lines or waveguides?
	a. Small size
	b. Extremely wide bandwidths
	c. Immunity to electromagnetic interference (EMI)
	d. Lower cost
	e. All the above
2	The most common light used in fiber-optic links is
	a. Infra-red
	b. Red
	c. Violet
	d. Ultraviolet
3	The optical band designation(s) include
	a. S
	b. C
	c. L
	d. a and b above
	e. All the above
4	In the telecommunications industry, the most commonly used fiber(s) are
	a. 50 micron
	b. 62.5 micron
	c. 50 and 62.5 micron
	d. 125 micron
5	The abrupt change in refractive index from core to cladding of fiber-optic cable is called the
	a. Total internal reflection
	b. Numerical aperture
	c. Dispersion
	d. Step index
6	A technique that is used to minimize the pulse dispersion effect is to
	a. Use a higher frequency light source
	b. Use plastic cladding
	c. Minimize the core diameter
	d. All the above
7	The loss (attenuation) of signal in optical fiber is due to
	a. Scattering
	b. Absorption
	c. Macrobending
	d. Microbending
	e. All the above
8	Calculate the optical power 100 km from a 0.5 mW source on a single mode fiber that has 0.10 dB per km loss.
	a. 50 nW
	b. 500 nW
	c. 5 uW
	d. 50 uW
9	Which is not an important characteristic of a light detector?
	a. Responsitivity
	b. Dark current
	c. Power consumption
	d. Response speed
	e. Spectral respons
10	The dispersion in fiber optics is termed
	a. Modal
	b. Chromatic
	c. Polarization mode
	d. All the above
	e. a and b above
11	Fiber optic connections suffer high loss due to
	a. Air gaps
	b. Rough surfaces
	c. Axial misalignment
	d. Angular misalignment
	e. All the above
12	Fiber optic technology is used in applications of
	a. Local area networks (LANs)
	b. Cable TV (CATV) systems
	c. Telephone networks
	d. All the above
13	The dispersion of light in fiber-optic cable caused by a portion of the light energy traveling in the cladding is called
	a. Modal dispersion
	b. Material dispersion
	c. Waveguide dispersion
	d. Cable dispersion
14	Recent laser developments for fiber optic communication include
	a. Distributed feedback (DFB)
	b. Heterojunction
	c. Vertical cavity surface emitting (VCSEL)
	d. a and b above
	e. a and c above
15	The following consideration is important when deciding between using a diode laser or an LED
	a. Response time
	b. Power levels
	c. Temperature sensitivity
	d. Failure characteristics
	e. All the above

Answers:

E

A

E

C

D

C

E

D

C

D

E

D

C

E

A

Electronic Communication by Gary Miller Chapter 16 with Answers

Chapter 16 Television

1	A television transmitter actually transmits two signals at once. They are
	a. An amplitude-modulated video signal and frequency-modulated audio signal
	b. Two amplitude-modulated signals: video and audio
	c. An amplitude-modulated audio signal and frequency-modulated video signal
	d. Two frequency-modulated signals: video and audio
2	The most widely used type of TV camera is the
	a. Charge couple device
	b. Vidicon
	c. Image orthicon
	d. Iconoscope
3	Synchronizing pulses that consist of equalizing pulses, followed by serrations, followed by more equalizing pulses at a rate of 60 times per second are called
	a. Color synchronizing pulses
	b. Horizontal retrace pulses
	c. Vertical retrace pulses
	d. Eight-cycle back-porch pulses
4	The frame frequency for U.S. television broadcasts is approximately
	a. 30 frames per second
	b. 40 frames per second
	c. 60 frames per second
	d. 100 frames per second
5	Channel 12 on U.S. television extends from 204 to 210 Mhz. The channel 12 carrier frequency is Approximately
	a. 204.5 Mhz
	b. 205.25 Mhz
	c. 211.25 Mhz
	d. 211.75 Mhz
6	The length of time an image stays on the screen after the signal is removed is termed
	a. Retention
	b. Flicker
	c. Persistence
	d. Back porch
7	Which is not part of the tuner section of a TV receiver?
	a. The rf amplifier stage
	b. The mixer stage
	c. The local oscillator stage
	d. The video-detector stage
8	The stage in a TV receiver that filters out the vertical and horizontal retrace pulses from the video signal is the
	a. Video detector
	b. Video IF amplifier
	c. Sync separator
	d. Sound detector
9	The winding around the CRT yoke that deflects the electron beam with its magnetic field is called the
	a. Coil
	b. Yoke
	c. Deflector
	d. Magneto
10	A cumbersome series of adjustments to a color TV receiver in order to make sure that the three electron beams of the picture tube are positioned exactly on their respective color dots on the face of the picture tube is called
	a. Alignment
	b. Convergence
	c. Interleaving
	d. Interlacing
11	A faulty TV receiver having symptoms of normal sound and raster but no picture must have a problem in the
	a. Horizontal or vertical oscillator or high-voltage power supply
	b. Main power supply
	c. Video amplifiers following the sound takeoff
	d. RF, IF, or video amplifiers prior to the sound takeoff
12	Raster refers to
	a. CRT illumination by scan lines when no signal is being received
	b. CRT resolution
	c. CRT aspect ratio
	d. All the above
13	The high voltage for the anode of the CRT is obtained from the low-voltage power supply using
	a. Its power-line transformer
	b. The yoke coil
	c. The vertical oscillator
	d. The flyback transformer
14	The introduction of digital television in the United States has been hampered by
	a. Delays in chip designs
	b. Shortages of appropriate chips
	c. Customer rejection
	d. Less than ideal regulatory climate
15	When a digital picture freezes even when there is motion in the video, it is
	a. due to bandwidth problems
	b. Called a pixelate
	c. Due to noise
	d. b and c

Answers:

A

A

C

A

B

C

D

C

B

B

C

A

D

D

D

Electronic Communication by Gary Miller Chapter 15 with Answers

Chapter 15 Microwaves & Lasers

1	Which is not a type of horn antenna design for microwave frequencies?
	a. Parabolic horn
	b. Circular horn
	c. Pyramidal horn
	d. Sectoral horn
2	Cassegrain feed to a paraboloid antenna involves a
	a. Dipole antenna
	b. Point-source antenna
	c. Secondary reflector
	d. Any of the above
3	Calculate the beamwidth of a microwave dish antenna with a 6-m mouth diameter when used at 5 Ghz.
	a. 0.49°
	b. 4.9°
	c. 7°
	d. 0.7°
4	Zoning refers to
	a. A method of producing a radome
	b. Changing a spherical wavefront into a plane wave
	c. Creating a polar radiation pattern
	d. Fading into nonreality
5	Which microwave oscillator has high gain, low-noise characteristics, and wide bandwidth?
	a. Traveling wave tube oscillator
	b. Gunn Oscillator
	c.Klystron oscillator
	d. Magnetron oscillator
6	Which is not an advantage of the Gunn gallium arsenide oscillator?
	a. Ease of removing heat from the chip
	b. Small size
	c. Ruggedness
	d. Lack of filaments
	e. Low cost of manufacture
7	The i in P-I-N diode refers to
	a. Indium
	b. Impact
	c. Integrated
	d. Intrinsic
8	Which is not a typical application of a ferrite in a microwave system?
	a. attenuator
	b. amplifier
	c. isolator
	d. circulator
9	A low noise microwave amplifier that provides amplification via the variation of a reactance is known as a
	a. Maser
	b. Laser
	c. Yig
	d. Parametric amplifier
10	The major difference between a laser and a maser is the
	a. Frequency of the signal being amplified
	b. Amplitude of the signal being amplified
	c. Bandwidth of the signal being amplified
	d. Phase of the signal being amplified
11	Lasers are useful in
	a. Industrial welding
	b. Surgical procedures
	c. Distance measuring
	d. Compact disc players
	e. All the above
12	The following semiconductor is not used as a microwave device:
	a. PIN diode
	b. Baritt diode
	c. Zener diode
	d. Tunnel diode
13	Which of the following represent typical failure mode(s) for a TWT amplifier?
	a. Low gain
	b. Spurious modulation
	c. Poor frequency response
	d. Low RF output
	e. All the above
14	Which of the following is not used as a microwave antenna?
	a. Patch antenna
	b. Marconi antenna
	c. Lens antenna
	d. Horn antenna
15	Compared to linear power supplies, switching power supplies are
	a. Less efficient
	b. More efficient
	c. Simpler d. Heavier Answers: A C D B A A D B D A E C E B B