ETEKETEK-1500-MOD-03

 ____    1.   Electromagnetic waves travel freely through space in all directions at the speed of light, or approximately ____ per second.

____    2.   Which of the following is an electromagnetic wave?

____    3.   Which of the following types of wave is imperceptible?

____    4.   When a digital signal needs to be transmitted over an analog medium, such as when a computer needs to send digital signals over an analog telephone line or TV cable, a device known as a(n) ____ is used.

____    5.   Which of the following units is used to measure frequency?

____    6.   The term ____ describes the rate of electrical flow.

____    7.   ____ modulation changes the number of waves representing one cycle.

____    8.   Television uses three types of modulation.  The video portion uses ____.

____    9.   Which digital modulation technique is similar to frequency modulation?

____   10.   ____ can occur intentionally from an external power source that amplifies the signal, or unintentionally when an RF signal bounces off an object and combines with the original signal to amplify it.

____   11.   When an RF signal moves from one medium to another of a different density the signal actually bends instead of traveling in a straight line.  This is known as ____.

____   12.   Which type of RF loss is caused by the equipment transmitting the signal?

____   13.   What is a problem with measuring RF loss using a linear scale?

____   14.   A loss of 10 decibels means that ____ percent of the power has been lost in mW.

____   15.   The maximum EIRP for IEEE 802.11b WLANs is ____ mW.

____   16.   The length of an antenna should be about ____ the wavelength.

____   17.   ____ polarization is typically used in wireless LANs with the dual antennas of access points pointing upward.

____   18.   What is the shape of a Fresnel zone?

____   19.   What is the free space loss (in dB) for IEEE 802.11b and 802.11g WLANs when the distance in meters is 100?

____   20.   A ____ dipole antenna produces a flatter signal than a standard dipole antenna.

____   21.   ____ antennas are used for long distance, point-to-point wireless links, such as connecting buildings that are up to 42 kilometers (25 miles) apart.

Matching

Match each term with the correct statement below.

____   22.   voltage multiplied by the current

____   23.   up-and-down wave

____   24.   orientation of the radio waves as they leave the antenna

____   25.   rate at which an event occurs

____   26.   bending caused by an object in the path of the transmission

____   27.   changes to a signal that can be made to enable it to carry information

____   28.   equal to current times resistance

____   29.   negative difference in amplitude between signals

____   30.   occurs when the RF signal comes in contact with elements in the air, such as rain or heavy dust particles

Short Answer

           31.   Why is it important to understand how wireless technology works?

           32.   What is the difference between an analog and digital signal?  Provide an example of each signal type.

           33.   What is amplitude modulation?

           34.   There are several advantages of digital modulation over analog modulation.  What are they?

           35.   There are several factors that may result in RF loss.  List and describe three of them.

           36.   How is RF power measured?

           37.   How does an antenna work?

           38.   What is polarization?

           39.   What is antenna diversity?

           40.   What is the most common type of antenna for a WLAN?