Communications Engineering Coaching Materials: Section 5 Module 22

This is the Section 5 Module 22 of the compiled Communications Coaching Materials taken from different sources including but not limited to Communications books, past Board Exams Questions, Journals and the Internet.

Communications Coaching Materials: Section  5 Module 22

This is the Section 5 Module 22 of the compiled Communications Coaching Materials taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies (EST), Communications Books, Journals and other Communications References. This particular Coaching Notes in Communications Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.

Communications Engineering Coaching: Section 5 Module 22



121. Corresponds to a resonant transmission line, and the dipole antennas describe so far have been resonant

Resonant antenna

122. Which of the following is referred to as true 3G


123. Bis means


124. Which of the following causes great damage to the cornea of the eye

Longer wavelength

125. Which of the following causes great damage to the retina of the eye

shorter wavelength

126. Variation delay form in ATM

Cell jitter

127. Embedded overhead bit


128. Commonly used in electro-optic crystal for polarization modulation

Lithium Niobate

129. Combination of circular and elliptical orbit


130. _______ ratio measures accuracy of cell transmission

Cell error

131. A coupler consist of series of lenses and partly reflective surfaces

Beam Splitting Coupler

132. Major difference of SONET and SDH

Data rate

133. Coherence of laser light is important to _______.


134. An optical detector for high sensitivity and bandwidth


135. Same information with dynamic range

Optical input power

136. Spectral width of laser in fiber optic


137. Spectral width of LED in fiber optic


138. Typical spectral width of laser ranges from 1nm to ____


139. Different packet types in X.25 switching


140. A single mode fiber optic cable has a diameter of


141. A step index multimode fiber optic cable has a diameter of


142. Packet switching

Layer 3

143. Thickness of optical disk


144. Used in 3D,.form depth video signal

Anti-logarithmic amplifier

145. Which of the following is not a fiber optic loss


146. Diameter of VSAT is between 0.3m to _______


147. Morning primetime block for AM in Metro Manila

5am to 9am

148. Parameter determines the range or the spectral length

Spectral response

149. Refers to variety of value added features

Control Information

150. Refers to mobile station identifier sent over on the air interface

Temporary Mobile Station Identifier

151. White streak


152. 16 bit network number (IP Addressing)

Class B

153. Illuminates only small portion of the fiber core

Effective Modal Bandwidth

154. National Building Code

PD 1096

155. Completely fills the core and the cladding of the front end of the fiber.

Overfilled launched bandwidth

156. Helium laser was discovered by A. Javen in


157. Ratio of the speed of air and the speed of another substance

Index of refraction

158. Number of electrons emitted per second times the electron charge


159. Integration of video, data in high speed

Fast Packet Concept

160. Laser light is bright mainly because it is


161. Angle separation of 8PSK


162. Wavelength dependence index of refraction

Modal Dispersion

163. An episode used to give sample of the style of a writer?


164. The Bandwidth of a fiber is limited to


165. The loudness of a sound depends upon the energy of motion imparted to ____________ molecules of the medium transmitting the sound.


166. What alloy is formed using Iron, aluminum and silicon used as videoheads in video recording tapes


167. A technique used in transmitting multiple copies of information over the network to avoid deep fade


168. In KBP television broadcasting, the commercial payload for a station should not exceed ________ minutes in Metro Manila


169. In KBP television broadcasting, each station should allot ____ minutes of newscast (local or foreign) from Monday to Friday


170. In acoustics, it is a sequential musical note


171. The harmonically related carrier (HRC) shifts all cable channels 2 to 125 down to frequency -1.25 MHz are done to what channel pairs?

3-4, 5-6, 4-6

172. The OSI layer responsible for network availability, data storage and process capacity

Session Layer

173. A type of error of which two or more data units have changed

Burst Error

174. Which of the following is/are true about Spectrum Management?

It performs forward error correction; It provides automatic congestion control in the upstream direction; It performs upstream frequency agility to avoid igress in noise

175. The time it takes for the intensity of sound energy in the room to drop to one millionth of its initial value

Reverberation time

176. The persistence of sound even after a sound reflection occurred


177. Which of the following is true about Consumer DSL

It has a data rate of 176 kbps in the upward direction; It has a data rate of 1Mbps in the downward direction; It has lower speech communication capability

178. In an empty GSM timeslot or certain timeslot, data service is sent to the direction of packet switch data over what GSM network


179. There are _________ primary unshielded twisted pair cables as classified by EIA/TIA 568 standard


Dead Zone

181. Is a modulation / multiplexing technique wherein the information and sidebands are distributed over very wide bandwidth

Spread Spectrum

182. Which of the following is true about UMTS?

The ITU-T named it IMT2000; Has packet data service; Has initial speed of 28.8 kbps

183. What modulation technique is used by GSM?

Frequency Hopping

184. A system which has access to all individual users of the entire network


185. A system which contains shared files to all individual users


186. A single transmission path from transmitter to receiver in the direction of line of sight range


187. A fixed cell length is how many bytes

53 bytes

188. Which of the following materials is sensitive to light?


189. A loss incurred of an electromagnetic wave travelling in a straight direction in a vacuum without absorption or reflection of medium of nearby objects

Free Space Path loss

190. An executive order regulating the operation of cable antenna television systems in the Philippines, and for other purposes

EO 205

191. An executive order which grants the NTC jurisdiction, control and regulation over the Philippine Commercial Satellite Corporation.

EO 196

192. A type of fiber optic cable which is always tightly buffered.

Plastic Clad Silica

193. It states that light wave behaves as if it is consists of many tiny particles

Quantum Theory

194. The highest central office in the DDD network

Regional Center

195. When a photodiode is used as fiber optic detector, it must be

Reversed bias

196. A diode used as an optical transmitter in fiber optics communication system


197. From mobile station to base station

Reverse Link

198. Refers to the number of electrons emitted per second, times the electron charge


199. A portion of the geosynchronous orbit where optimum coverage of a country is known as __________ location

Arc of Good

200. A geosynchronous satellite must be positioned at _______

0 degrees latitude

201. How many polar satellites are needed to complete one revolution


202. A licensed ECE is needed if a station transmit power exceeds?



204. For a music lover concert “A” is 440 Hz, if a musical note one octave higher were played, it would be ____ that frequency


205. In a 220 Hz tone, an octave lower will result to ________?


206. The digital signal level __ uses binary line coding scheme


207. Voice channels are also known as

Traffic channel

208. Connects to other offices and does not go directly to subscribers

Tandem Office

209. In a telephone channel bandwidth of 300 to 3000 Hz, the highest theoretical bandwidth rate is

5400 bps

210. With 8-bit processing, how many elements are contained in the channel?

2048 ports

211. What happens to the frequency and wavelength of a material if it enters from one medium to another type of medium with a change in speed?

The frequency remains the same but the wavelength changes

212. The main benefit of light-wave communications over microwaves or any other communications media

Wider bandwidth

213. Microwave communications is used in frequencies above?


214. Waveguide becomes compulsory above what frequencies?


215. It refers to an electromagnetic wave of which it is contained in a conduit

Guided Transmission Medium

216. What is the average loss in fiber splice?

0.15 dB

217. Is the sound energy per unit area at right angles of the propagation direction per unit time

Sound Intensity

218. Octave A ratio of two frequencies at


219. Pin 21 in the RS 232 Interface D connection

Signal Quality detector

220. An additional noise attributed to wind and environmental noise


221. Refers to the direction of the electric field vector in space


222. Is an antenna array which is highly directional at right angles to the plane of the array

Broadside Array

223. The transmission of information from multiple sources occurring on the same facility but not at the same time


224. The most widely used fax standard

Group III

63, 535 octets

226. The highest layer in the ISO protocol Hierarchy

Application Layer

227. Is a non-coherent light source fo optical communications system


228. Which of the following is used as an optical receiver in fiber optics communications


229. Is the result of photons of light that are absorbed by the atoms of the glass core molecules

Infrared Absorption

230. What parameter of light detector determines the range or system length that can be achieved for a given wavelength?

Spectral Response

231. Dark current in light detectors is caused by?

Thermally generated carriers in the diode

232. What is the typical wavelength of light emitted from epitaxially grown LEDs?

940 nm

233. Which is not a possible cause of fiber optic loss?

Stepped Index Operation

234. When light strikes a flat polished end of a fiber, it produces a loss of?


235. An increase in light intensity produces fast optic switching due to?

Amplification of optical signal

236. Optical fibers for telecommunications are typically about ___ mils thick and consist of a glass core, a glass cladding of lower index of refraction, and a protective coating


237. Material dispersion is caused by the?

Wavelength dependence of the index of refraction

238. One of the following is not a solid state optical detector?


239. Which optical detector is used when high sensitivity and bandwidth are required?


240. A radio station has a _ years of legal operation and shall renew for the same duration of operation


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