题目内容
（请给出正确答案）
A.Gain of both frequency diversity and interference diversity
B.Gain of frequency diversity only
C.Gain of interference diversity only
D.Neither gain of frequency diversity nor gain of interference diversity
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更多“ “1*3” reuse, radio frequency …”相关的问题
A.4*3
B.7*3
C.1*3
D.MRP
The first country artists to be widely known achieved popularity in the late 1920s. The music of these performers was heard throughout tile south during the 1920s and 30s on radio programs.
By the 1950s, country music had become a significant force in pop music. Regular appearances on the radio show made stars of many performers. The singer-songwriter Hank Williams wrote four million-seller songs in 1950, seven in 1951, and four more in 1953.
By the 1970s, "some country musicians began combining country music with electric instruments, creating a country rock sound.
What does "Both styles" in Line 3, Paragraph 1 refer to？
A．Country music style. and the musical style. of the Southeastern states.
B．The musical styles of the Southwestern states and the Southeastern states.
C．The Southwestern musical style. and Texas musical style.
D．The styles of blues and the black rural dance music.
cancer. originally,because of a lawsuit that alleged such a link Network news programs ran their own tests of cell phones,reporting to the public that some cell phones exceed the maximum level of emitted radio frequency energy allowed by the US Federal Communications Commission.
In 2000.it was estimated that there were 92 million cell phone users in the United States and this number was growing by 1 million every month. More recently,the Cellar Telecommunications & Internet Association estimated that there were almost 170 million US cell phone users, and the seriousness of brain tumours, this is clearly a topic of wide concern.This report summarizes what we now know about the carcinogenicity of using cell phones.
Cell phones operate with radio frequencies.a form. of energy located on the electromagnetic spectrum between F M radio waves and the waves used in microwave ovens,radar;and satellite stations.Cell phones do not emit ionizing radiation,the type that damages DNA and is known to have the ability to cause cancer.
Cell phone technology works on a system of geographically separated zones called "cells" Each cell has its own "base station" that both receives and emits radio waves.When a call is placed from a cell phone,a signal is sent from the cell phone antenna to that cell's base station antenna.The base station responds to the cell phone signal by assigning the phone an available RF channel.When the RF channel is assigned,radio signals are simultaneously received and transmitted, allowing voice information to be carried between the cell phone and the base.The base station transfers the call to a switching centre.where the call can be transferred to a local telephone carrier or another cell phone.
6.There has existed argument about the link between cell phone and brain tumour.()
7.The rapid growing number of cell phone users has been a great concern in the US.()
8.The 3rd paragraph tries to prove that cell phones do not cause brain cancer.()
9.A switching centre is needed when we make a call through cell phone.()
10.The topic of the passage is about cell phone and cancer.()
Bm, the cable losses 3 dB, and the antenna gain 14 dBd？()
A.43dBm
B.26dBm
C.32dBm
D.60dBm
E.54dBm
requency re.use in the network)？()
A.It increases the sensitivity of the mobile
B.It increases the number of mobiles with high C/I
C.The power consumption in the radio base station is reduced
D.It reduces the risk of MS receiver saturation
E.It reduces the number of mobiles with low C/I
A.f◦f
B.f◦g
C.g◦g
D.g◦f
