This is the Multiple Choice Questions in Chapter 22: Personal Communications Systems from the book Electronic Communication Systems by Roy Blake
Start Practice Exam Test Questions
Choose the letter of the best answer in each questions.
MULTIPLE CHOICE
1. Current PCS systems are referred to as:
- a. first-generation
- b. second-generation
- c. third-generation
- d. digital-generation
ANS: B
2. The frequency band designated for PCS in North America is:
- a. 800 MHz
- b. 900 MHz
- c. 1.9 GHz
- d. 12 GHz
ANS: C
3. The "forward" PCS channel is:
- a. from the base to the mobile
- b. from the mobile to the base
- c. from mobile to mobile
- d. same as the uplink
ANS: A
4. Compared to AMPS, PCS cell sites are:
- a. bigger
- b. smaller
- c. distributed
- d. higher-power
ANS: B
5. AMPS was designed for:
- a. POTS
- b. voice
- c. use built into an automobile
- d. all of the above
ANS: D
6. The number of competing PCS systems in North America is:
- a. 2
- b. 3
- c. 4
- d. many
ANS: B
7. CDMA technology was invented by:
- a. AT&T
- b. Lucent
- c. Bell Labs
- d. Qualcomm
ANS: D
8. GSM is used in:
- a. Asia
- b. Europe
- c. North America
- d. all of the above
ANS: D
9. In GSM, voice channels are called:
- a. traffic channels
- b. voice channels
- c. bearer channels
- d. talking channels
ANS: A
10. AMPS uses:
- a. CDMA
- b. TDMA
- c. spread-spectrum
- d. none of the above
ANS: D
11. Other things being equal, battery life in a GSM phone should be:
- a. less than in a TDMA phone
- b. no better than in an AMPS phone
- c. greater than in a TDMA phone
- d. no better than a TDMA phone
ANS: C
12. It is necessary to send control information on traffic channels in:
- a. no PCS system
- b. GSM only
- c. TDMA only
- d. both GSM and TDMA
ANS: D
13. GSM uses:
- a. frequency hopping
- b. direct-sequence modulation
- c. CDMA
- d. all of the above
ANS: A
14. In GSM, SIM stands for:
- a. Short Inbound Message
- b. Subscriber-Initiated Message
- c. Subscriber ID Module
- d. Subscriber ID Method
ANS: C
15. IMSI stands for:
- a. Integrated Mobile Subscriber Identification
- b. International Mobile Subscriber Identification
- c. Interim Mobile Subscriber Identification
- d. Intermodulation System Interference
ANS: B
16. IS-95 uses:
- a. frequency hopping
- b. TDMA
- c. CDMA
- d. all of the above
ANS: C
17. IS-136 uses:
- a. frequency hopping
- b. TDMA
- c. CDMA
- d. all of the above
ANS: B
18. In CDMA:
- a. all frequencies are used in all cells
- b. each cell uses half the available frequencies
- c. each cell is assigned a frequency by the base
- d. the frequency is selected by the mobile phone
ANS: A
19. CDMA uses a set of PN sequences that are:
- a. common
- b. unique
- c. rotating
- d. orthogonal
ANS: D
20. The next generation of PCS is expected to have:
- a. faster data rates
- b. Internet access
- c. wider roaming area
- d. all of the above
ANS: D
COMPLETION
1. PCS stands for ____________________ Communications System.
ANS: Personal
2. Current PCS systems are called ____________________-generation systems.
ANS: second
3. In North America, PCS is assigned the ____________________-MHz band.
ANS: 1900
4. Compared to AMPS, PCS cells are ____________________ in size.
ANS: smaller
5. Besides TDMA and CDMA, ____________________ is also used in North America for PCS.
ANS: GSM
6. The spread-spectrum technique used in IS-95 PCS is ____________________.
ANS:
CDMA
direct sequence
7. The spread-spectrum technique used in GSM is _________________________.
ANS: frequency hopping
8. Unlike AMPS, CDMA allows for a ____________________ handoff.
ANS: soft
9. The orthogonal PN sequences used in CDMA are called a ____________________ code.
ANS: Walsh
10. Unlike other systems, in CDMA ____________________ frequencies are used in all cells.
ANS: all
11. PN stands for Pseudo-____________________ Noise.
ANS: random
12. ____________________ diversity is inherent in any spread-spectrum system.
ANS: Frequency
13. RF channel S/N ratios ____________________ than zero are typical in CDMA systems.
ANS: less
14. CDMA uses a ____________________-rate vocoder.
ANS: variable
15. A phone user typically talks less than ____________________% of the time during a conversation.
ANS: 50
16. CDMA requires ____________________-loop power control to work properly.
ANS: closed
17. GPRS stands for General ____________________ Radio Service.
ANS: Packet
18. IMT stands for International ____________________ Telecommunications.
ANS: Mobile
19. UPT stands for ____________________ Personal Telecommunications.
ANS: Universal
20. UWT stands for Universal ____________________ Telecommunications.
ANS: Wireless
21. W-CDMA stands for ____________________ CDMA.
ANS: Wideband
SHORT ANSWER
1. What is the advantage of a "soft" handoff?
ANS:
No calls are dropped.
2. If CDMA receivers hear all frequencies all the time, how do they pick a specific frequency?
ANS:
Each frequency is modulated using a separate orthogonal PN sequence. To demodulate, the receiver uses the PN sequence specific to the channel it wants.
3. What is the effect of cochannel interference in CDMA?
ANS:
It increases the background noise level, but CDMA can tolerate a lot of such noise.
4. How does GSM achieve frequency diversity?
ANS:
It uses limited frequency hopping.
5. Why was PCS assigned to 1.9 GHz instead of the 800-MHz band used for AMPS?
ANS:
The 800 MHz band was already overcrowded.
6. Why would a battery in a GSM phone be expected to last longer than a battery in a TDMA phone?
ANS:
A TDMA phone is active during one out of every three time slots. A GSM phone is active during one out of every eight.
7. What is the advantage of using offset QPSK over standard QPSK?
ANS:
With standard QPSK, the transmitted power repeatedly goes to zero. With offset QPSK, it never goes to zero. Linearity requirements are less strict for offset QPSK transmitters.
8. What is the "near/far" effect in CDMA, and what causes it?
ANS:
A stronger station farther away can "drown out" a weaker station that is near. This happens when the power transmitted by mobile units is not well controlled by the base.
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