Modern Electronic Communication by Gary Miller Chapter 9 with Answers

Chapter 9 Digital Communications Transmission

1	Using an oscilloscope to display overlayed received data bits that provide information on noise, jitter, and linearity is called a(n)
	a. Constellation pattern
	b. Loopback
	c. Statistical Concentration
	d. Eye pattern
2	Why isn't Morse code well suited to today's telegraphic equipment?
	a. It uses an automatic request for repetition.
	b. It has excessive redundancy built into the code.
	c. The parity bit is difficult to detect.
	d. Differing between various widths of the pulses is an extremely complicated process.
3	A special digital modulation technique that achieves high data rates in limited-bandwidth channels is called
	a. Delta modulation
	b. Pulse-coded modulation (PCM)
	c. Quadrature amplitude modulation (QAM)
	d. Pulse amplitude modulation (PAM)
4	FSK systems are much superior to two-tone amplitude-modulation systems with respect to
	a. Noise performance
	b. Bandwidth requirements of the channel
	c. Ionospheric fading characteristics
	d. Power consumption
5	Which is not a type of pulse modulation?
	a. Pulse-amplitude modulation (PAM)
	b. Pulse-width modulation (PWM)
	c. Pulse-frequency modulation (PFM)
	d. Pulse-position modulation (PPM)
6	PPM and PWM are superior to PAM systems in
	a. Noise characteristics
	b. Bandwidth characteristics
	c. Simplicity in design
	d. Frequency response of the intelligence signal
7	Half-duplex operation involves communication
	a. In one direction only
	b. In both directions, but only one can talk at a time
	c. Where both parties can talk at the same time
	d. All the above
8	A procedure that decides which device has permission to transmit at a given time is called
	a. Line control
	b. Protocol
	c. Flow control
	d. Sequence control
9	The technique that uses the BPSK vector relationship to generate an output with logical 0s and 1s determined by comparing the phase of two successive data bits is
	a. CSU/DSU
	b. TDM
	c. CVSD
	d. DPSK
10	Using radio to transmit gathered data on some particular phenomenon without the presence of human monitors is known as
	a. Radio teletype
	b. Radio multiplexing
	c. Radio facsimile
	d. Radio telemetry
11	The bit error rate is
	a. The number of bit errors that occur for a given number of bits transmitted
	b. The most common method of referring to the quality of a digital communication system
	c. Virtually the same as the error probability
	d. All the above
12	The major difficulty faced by delta modulators is
	a. Excessive noise producing errors
	b. Slope overload
	c. Insufficient frequency response of the intelligence signal
	d. Complexity of design
13	The capacity of a telephone channel that has an S/N of 2047 if its bandwidth is 3.5 kHz is
	a. 30,000 bits per second
	b. 33,000 bits per second
	c. 38,500 bits per second
	d. 35,000 bits per second
14	The AT&T T1 lines
	a. Use 16-bit PCM code and include 24 voice channels
	b. Use delta modulation and include 48 voice channels
	c. Use 8-bit PCM code and include 24 voice channels
	d. Use delta modulation and include 24 voice channels
Answers; Chapter 9 Digital Communications Transmission 1 Using an oscilloscope to display overlayed received data bits that provide information on noise, jitter, and linearity is called a(n) a. Constellation pattern b. Loopback c. Statistical Concentration d. Eye pattern 2 Why isn't Morse code well suited to today's telegraphic equipment? a. It uses an automatic request for repetition. b. It has excessive redundancy built into the code. c. The parity bit is difficult to detect. d. Differing between various widths of the pulses is an extremely complicated process. 3 A special digital modulation technique that achieves high data rates in limited-bandwidth channels is called a. Delta modulation b. Pulse-coded modulation (PCM) c. Quadrature amplitude modulation (QAM) d. Pulse amplitude modulation (PAM) 4 FSK systems are much superior to two-tone amplitude-modulation systems with respect to a. Noise performance b. Bandwidth requirements of the channel c. Ionospheric fading characteristics d. Power consumption 5 Which is not a type of pulse modulation? a. Pulse-amplitude modulation (PAM) b. Pulse-width modulation (PWM) c. Pulse-frequency modulation (PFM) d. Pulse-position modulation (PPM) 6 PPM and PWM are superior to PAM systems in a. Noise characteristics b. Bandwidth characteristics c. Simplicity in design d. Frequency response of the intelligence signal 7 Half-duplex operation involves communication a. In one direction only b. In both directions, but only one can talk at a time c. Where both parties can talk at the same time d. All the above 8 A procedure that decides which device has permission to transmit at a given time is called a. Line control b. Protocol c. Flow control d. Sequence control 9 The technique that uses the BPSK vector relationship to generate an output with logical 0s and 1s determined by comparing the phase of two successive data bits is a. CSU/DSU b. TDM c. CVSD d. DPSK 10 Using radio to transmit gathered data on some particular phenomenon without the presence of human monitors is known as a. Radio teletype b. Radio multiplexing c. Radio facsimile d. Radio telemetry 11 The bit error rate is a. The number of bit errors that occur for a given number of bits transmitted b. The most common method of referring to the quality of a digital communication system c. Virtually the same as the error probability d. All the above 12 The major difficulty faced by delta modulators is a. Excessive noise producing errors b. Slope overload c. Insufficient frequency response of the intelligence signal d. Complexity of design 13 The capacity of a telephone channel that has an S/N of 2047 if its bandwidth is 3.5 kHz is a. 30,000 bits per second b. 33,000 bits per second c. 38,500 bits per second d. 35,000 bits per second 14 The AT&T T1 lines a. Use 16-bit PCM code and include 24 voice channels b. Use delta modulation and include 48 voice channels c. Use 8-bit PCM code and include 24 voice channels d. Use delta modulation and include 24 voice channels 15 A digital transmission has an error probability of and is long. Its expected number of error bits is a. b. c. d.