Digital Communications1.docx

Digital Communications1. Which of the following is rarely used indigital communication systems?a. ASK b. FSK c. PSK d. QAMAnswer:2.Info

rmation capacity is directly proportio nal toa. Bit rate b. Baud ratec. C/Nd. BandwidthAnswer:3 .Which of the following does not makesefficient use of available bandwidth?a.

FSK b. PSK c. QAMd. ASK Answer:

4. Which of the following is usedextensively in high-frequency radioteletype transmission?a.

QAM b. FSK c. PSK d. ASK Answer:5 . Q A M u s e s a. PSK b. ASK c. PCMd. MSK Answer:6.Dig ital amplitude modulation is calleda. ASK b.

FSK c. MSK d. PSK Answer:

7. A system that provides highspeedinternet access using regular telephonelin es.a. ISDN b. DSLc.

WAPd. WiFiAnswer: B

8. Downstream speeds of ADSL typicallyrang e from

a.

64 kbps to 1.5 Mbps b. 56 kbps to 8 Mbps

c. 768 kbps to 9 Mbpsd. 128 kbps to 2 MbpsAnswer:

9.

Upstream speeds of ADSL typicallyrange from

a. 64 kbps to 1.5 Mbps b. 56 kbps to 8 Mbps

c.

768 kbps to 9 Mbpsd. 128 kbps to 2 MbpsAnswer:

10. In DSL technology, it is the proprietarytechn ology trademarked by RockwellInternat ional. ?a. IDSL b.

CDSLc. RDSLd. ADSLAnswer:

11. Uses the advanced signal modulationtec hniques of DSL and combines themwith the half-duplex "bur st" packetnature of Ethernet.a. xDSL b.

EthernetLoopc. ISDNd. WAPAnswer:12.A type of DSL in which the upstreamand downstream speeds are unequal or uneven.a. RDSL b. ADSLc.

HDSLd. IDSLAnswer:

13. Which xDSL generally used as asubstitute for T1/E1?a. HDSL b. SDSLc. IDSLd. RADSLAnswer:14. A lower data rate

version of Asymmetric Digital Subscriber Line(ADSL) was been proposed as anextension to ANSI standard T1.4