1. Which modulation scheme is preferred for direct sequence spread spectrum process?
Correct : C. bpsk & qpsk
2. The processing gain is given as modulation scheme.
Correct : A. wss/r
3. The minimum spacing between consecutive hop positions gives the
Correct : A. minimum number of chips necessary
4. Which system allows larger processing gain?
Correct : B. frequency hopping
5. In which technique is phase coherence hard to maintain?
Correct : B. frequency hopping
6. Which type of demodulator is used in the frequency hopping technique?
Correct : B. non coherent
7. Robustness gives the inability of a signal to withstand the impairments.
Correct : B. false
8. Chips are the
Correct : A. repeated symbols
9. Slow frequency hopping is
Correct : B. several modulations per hop
10. Fast frequency hopping is
Correct : D. none of the mentioned
11. Which duration is shorter?
Correct : A. hop duration
12. Frequency division multiple access (FDMA) assigns channels to users.
Correct : A. individual, individual
13. If the FDMA channel is not in use, it can be used by other users.
Correct : B. false
14. The bandwidth of FDMA channel is
Correct : B. narrow
15. Which of the following is not true for FDMA systems as compared to TDMA systems?
Correct : B. lower cell site system cost
16. is undesired RF radiation.
Correct : A. intermodulation frequency
17. is based on FDMA/FDD.
Correct : D. amps
18. In US AMPS, 416 channels are allocated to various operators with 10 kHz guard band and channel between them is 30 kHz. What is the spectrum allocation given to each operator?
Correct : C. 12.5 mhz
19. TDMA systems transmit in a continuous way.
Correct : B. false
20. are utilized to allow synchronization of the receivers between different slots and frames.
Correct : C. guard bits
21. Which of the following is not true for TDMA?
Correct : A. single carrier frequency for single user
22. Because of transmissions in TDMA, the handoff process in
Correct : D. discontinuous, simple
23. synchronization overhead is required in TDMA due to transmission.
Correct : A. high, burst
24. TDMA allocates a single time per frame to different users.
Correct : B. false
25. of TDMA system is a measure of the percentage of transmitted data that contains information as opposed to providing overhead for the access scheme.
Correct : A. efficiency
26. What is the time duration of a bit if data is transmitted at 270.833 kbps in the channel?
Correct : C. 3.692 μs
27. US digital cellular system based on CDMA was standardized as
Correct : C. is-95
28. IS-95 was not compatible with existing AMPS frequency band.
Correct : B. false
29. Which of the following is used by IS-95?
Correct : A. dsss
30. IS-95 uses same modulation technique for forward and reverse channel.
Correct : B. false
31. IS-95 is specified for reverse link operation in band.
Correct : D. 824-849 mhz
32. User data in IS-95 is spread to a channel chip rate of
Correct : A. 1.2288 mchip/s
33. are used to resolve and combine multipath components.
Correct : C. rake receiver
34. CT2 was the first generation of cordless telephones.
Correct : B. false
35. CT2 is analog version of first generation cordless telephones.