●In the following essay，each blank has four choices．Choose the best answer and write down

on the answer sheet．

Spread spectrum simply means that data is sent in (66) pieces over a number of the discrete frequencies available for use at any time in the specified range．Devices using (67) spread spectrum(DSSS)communicate by splitting each (68) of data into several parts and sending them concurrently on different (69) ,DSSS uses a lot of the available (70) ，about 22 megahertz(MHz)．

(66) A．small

B．high

C．low

D．long

(67) A．direct-sequence

B．discrete-sequence

C．duplicate-sequence

D．dedicate-sequence

(68) A．data

B．byte

C．packet

D．bit

(69) A．bits

B．frequencies

C．packets

D．messages

(70) A．rate

B．velocity

C．bandwidth

D．period

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更多“●In the following essay，each blank has four choices．Choose the best answer and write down”相关的问题

第1题

Which of the following is the encryption algorithm used for priv option when using SNMPv3（）

A.HMAC-SHA

B.HMAC-MD5

C.BC-DES

D.ES

E.3DES

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第2题

Router R1 lists the following output from a show command. Which of the following is true a

bout R1？（）R1 show ip v6 interface f0/0FastEthernet0/0 is up, line protocol is upIPv6 is enabled, link - local address is FE80::213:19FF:FE12:3456No Virtual link - local address(es):Global unicast address(es):2000::4:213:19FF:FE12:3456, subnet is 2000:0:0:4::/64 [EUI]Jo ined group address(es):FF02::1FF02::2FF02::1:FF:12:3456

A. R1‘s solicited node multicast address is FF02::1:FF:12:3456.

B. R1‘s 2000::4:213:19FF:FE12:3456 address is a global unicast with all 128 bits statically configured.

C. Address FF02::2 is R1‘s solicited node multicast.

D. R1‘s solicited node multicast, not listed in this output, would be FF02::213:19FF:FE12:3456.

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第3题

ES纤维是______。

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第4题

间隙配合最小间隙Xmin（)。

A.ES–ei

B.EI–es