COACHING APRIL 07 (COMM1) Impedance matching ratio of coax balun.

4:1 A continuous tone generated by the combination of frequencies 350Hz to 440Hz used in telephone sets.

Call waiting tone A component in the telephone set that has the primary function of interfacing the handset to the local loop.

Induction coil A telephone wire that connects 2 central offices.

Trunk line A component in the telephone set that has the primary function of compensating for the local loop length.

Varistor A special service circuit connecting 2 private branch exchanges (PBX).

Tie trunk When was the 1

st Strowger step-by-step switch used?

1897 Coaxial cable impedance is usually __________

50 and 75 Commonly used telephone wire

AWG #19 Distortion enhances intelligibility when an __________ is added.

Exciter Consists of a rapid succession of noticeable echoes.

Flutter echo The average absorption for a person is __________

4.7 units The type of emission that suffer most from selective fading.

FM and double sideband AM Which component is used to produce AM at very high freqz?

PIN diode What theorem set a limit on the maximum capacity of a channel w/ a given noise level? Shannon-Hartley theorem ____________is measured on a circuit when it is correctly terminated but does not have any traffic.

White noise Which standard recommends crosstalk limits?

CCITT G. 151 Which standard is utilized in intermodulation noise rates on PCM audio channels?

CCITT Rec. G. 172 What is the reference frequency of CCITT phosphometric noise measurement?

800 Hz nif stands for

Noise improvement factor A large emission of hydrogen from the sun that effects communications.

Solar flare The solar cycle repeats the period of great electrical disturbance approximately every

11 years Who profounded electromagnetic radiation theory?

James Clerk Maxwell A range of microwave frequencies more easily passed by the atmosphere than are the others is called a

Window Tropospheric scatter is used with frequencies in the following range

UHF The ground wave eventually disappears as one moves away from the transmitter, because of

Tilting The quality in sound that corresponds to color in light is

Pitch The brightness of light source is called its luminous intensity, whose unit is

Candela The minimum illumination recommended for reading is

8000lx Each point on a spherical waveform maybe a source of a secondary spherical wavefront.

Huygens principle In testing transmitter to prevent interfering with other stations, which type of antenna must be used?

Dummy antenna Typical speech power

10 to 1000 uW Cellular phones transmit in the band from

825 to 845 MHz Cell phone receives in the band from

870 to 890 MHz The range (in miles) of a cellular CDMA system.

13 SYN character of EBCDIC code.

32 H What are the steps to follow to produce a PCM signal?

Sampling, quantizing and coding A transmission where data are inputted directly on the cable.

Baseband A network operating system within several building in compound.

Novell Netware Defined as a figure of merit used to express the degree of modulation achieved in an FSK modulator.

H Factor Which is considered as the fastest LAN topology?

Bus What is the other name for parity?

VRC What ferrite device can be used instead of duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna?

Circulator Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction?

Isolator Which of the following is used as a high-power microwave oscillator?

Magnetron The smallest beam of a satellite antenna radiation pattern.

Spot beam A satellite beam that covers almost 42.4% of the earths surface.

Global beam Founded the wave theory of light.

Christian Huygens Fiber optic cables operate at frequencies near

800 THz What is the lifetime of LEDs?

200,000 hours

What is the lifetime of ILDs? 50,000 hours

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.

5 A mechanism or device which enables the TV camera to move in lateral and tilting motion.

Pan/tilt device The aspect ration of HDTV is

16.9 The time duration for one horizontal trace.

52 us A law prescribing the functions of the National Telecommunications Commission.

E.O. 546 An order providing for a national policy on the operation and use of international satellite communications in the country.

E.O. 467 Policy to improve the provision of local exchange carrier service.

E.O. 109 The first symbol of emission is

The type of modulation of main carrier The second symbol of emission is

The nature of signals modulating the main carrier

The third symbol of emission is

The type of information to be transmitted The maximum ground resistance in an equipment installation as required by Volume 1 of the Philippine Electronic Code (Safety Code) is

5 ohms COMM2 One of the reasons why FDM is being replaced by TDM is

Noise is amplified w/ voice when an FDM is used

What kind of receiver is used in conventional telephone handset?

Electromagnetic Low-power radar uses

IMPATT

A source code whose average word length approaches the fundamental limit set by the entropy of a discrete memoryless source.

Huffman code The allowable deviation ratio of commercial FM broadcast

5 What freqz does oxygen causes excessive attenuation?

60 GHz What is the signal-to-noise ratio required for satisfactory telephone service?

50 dB The use of telecommunication for automatic indicating or recording measurement at the distance from the measuring instrument.

Telemetry What consists the front-end circuit of a VHF TV superhet receiver?

Local oscillator, mixer and RF amp What satellite subsystem monitors onboard conditions such as temperature and battery voltage and transmits this data to a ground station for analysis

TTC What is the typical center freqz spacing between adjacent channels in satellites?

40 MHz What material is most often used for the outer covering of coaxial cables?

PVC What is the dielectric constant of PE insulator?

2.27 What is the typical velocity factor of open-wire line?

0.9 twin-lead?

0.8 What info is related to mental process of knowledge, reasoning, memory, judgment and perception?

Cognitive What sound characteristic relates to sonic time pattern?

Rhythm What do you call the perceptible sound repetition?

Echo What is the amount of sound reduction provided by barrier wall, floor, or ceiling called?

Transmission loss What is the velocity of sound in wood?

3300 m/s Which of the ff is NOT an acoustical defect to be avoided in acoustical designs?

Reverberation What is the term used to describe a spread spectrum communications system where the center freqz of a conventional carrier is altered many times per second in accordance w/ a pseudo-random list of channels?

Frequency hopping Tropospheric scatter is a method of sky wave propagation for w/c of the ff freqz bands?

300 MHz to 3 GHz The antenna effective height is _________ of the actual height.

- What is the end impedance of a half wave dipole?

2500 What devices measures the angle between 2 radio freqz and also the direction of propagation of a wave?

Goniometer In cellular system, the average lead time to install a new base station is approximately

6 mos to 1 year At one atmospheric pressure, what is the approx speed of sound in steel?

5150 m/s Atmospheric attenuation is due to

Water vapor and oxygen Satellite orbits around the earth are __________ orbits.

Elliptical or circular The American concert pitch A is equivalent to

440 Hz international pitch A?

435 Hz What is affected by the distance between the listener and the source of the sound because the intensity varies inversely w, the square of the distance?

Loudness Comparing the capacities of a DVD and an ordinary CD, DVD is ________ times bigger than CD.

5 times What causes MUF to vary?

The amount of radiation received from the sun

COMMUNICATIONS Topic: Communications (All)

1. The effective refraction index of the ionosphere for radio waves is: ? less than unity (Correct Answer) 2. If a fiber optic system has a rise time of 16ns, the source rise time is 1.5ns and the detector rise time is 2ns, what is the cable rise time? ? 14 ns (Correct Answer) 3. Earth station uses what type of antenna. ? Cassegrain antenna (Correct Answer) 4. The minimum number of turns a helix antenna must have. ? 3 (Your Correct Answer) 5. A local area network in which, rather than all users sharing the media, a central switch routes traffic between only those parts that require it: ? Switched LAN (Correct Answer) 6. A method of snooping through the internet for files and retrieving them. ? Gopher (Correct Answer) 7. A tag based ASCII programming language that is used to specify and links to other documents on the World Wide Web servers on the Internet (HTML for short). ? Hypertext markup language (Your Correct Answer) 8. A passive circuit, usually consisting of capacitance and/or inductance, that is inserted in series with the a-c power cord of an electronic device which will allow the 60 - Hz current to pass and suppressed high-frequency noise components. ? noise filter (Your Correct Answer) 9. Transmission for the cell site to receive calls from the users: ? Reverse Link (Correct Answer) 10. Which of the following network access methods sends a signal indicating its intent to transmit data on the wire? [Choose the best answer] ? CSMA/CA (Correct Answer) 11. Frequencies in the UHF range propagate by means of which of the following?

Ans: Space waves 12. Digital modulation scheme that represents a bit pattern by a change in phase from the previous state. Ans: DPSK 13. How much does the radiated power of an antenna increases if its current increases by 3.3 times? Ans: 10.89 times 14. A process using uudecode to decode a file encoded for network transmission by uuencode, a UNIX utility program. Ans: extraction 15. Which statement is true? Ans: changing the length of the wire will have no effect on the SWR 16. What is the ratio of the power radiated by the antenna to the total input power? Ans: antenna efficiency 17. For proper operation, a magnetron must be accompanied by a Ans: permanent magnet 18. Parabolic and lens are extremely used for Ans: microwaves 19. A GSM criterion that is measured as the number of simultaneous conversations per MHz per km2. Ans: Spectral Efficiency 20. In the _____ layer, translation from one character code to another occur. Ans: presentation 21. ______ detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. Ans: LNA 22. Quantizing noise is present in ______ system. Ans: PCM 23. What is the function of a redirector? Ans: Forwards requests to local or remote resource hosts

24. Data services that provide the capacity necessary to transmit appropriate data signals between two access points. Ans: Bearer Services 25. A feature of PCS that notifies users that they have voice mail messages. Ans: Message Waiting Indicator (MWI) 26. The center of a network which is based on a star TOPOLOGY. Ans: Hub 27. ____ is the central office for mobile switching. Ans: MTSO 28. It is fictitious resistance that dissipates as much power as an antenna is radiating if it were connected to the same transmission line. Ans: radiation resistance 29. The published rates, regulations, and descriptions governing the provision of communications service for public use. Ans: Tariff 30. Provide post equalization to the received analog signal. Ans: Adaptive equalizers 31. One of the reasons why FDM is being replaced by TDM Ans: Noise is amplified with voice when an FDM system is used 32. ______ is the measurement of unilateral antenna properties of directivity. Ans: beamwidth 33. In a klystron amplifier, velocity modulation of the electron beam is produced by the Ans: catcher cavity 34. Refers to a type of beam antenna that uses two or more straight elements arranged in line with each other. Ans: Yagi antenna 35. A type of array antenna which consists of one half-wave driven dipole, one reflector and one director. Ans: Yagi-Uda

36. What is the modulation rate of the CCITT V.26 modem? Ans: 1200 bauds 37. The distance between the two antennas of a geostationary satellite system is 22,300 miles and is operating at a downlink frequency of 12.2 GHz, what is the free space loss in dB? Ans: 205 dB 38. It covers links between satellites and fixed earth stations. Ans: Fixed Satellite service (FSS) 39. Maximum Ethernet segment length for thick wire. Ans: 500 m 40. You are measuring noise in a voice channel at a-4 dB test point level, the meter reads -73 dBm, convert the reading into dBrnCO. Ans: 21 41. AMPS is the short for ____, an analog cellular standard developed in the USA and primarily employed there and in Asia-Pacific. Ans: Advanced Mobile Phone System 42. Antenna that is not properly terminated Ans: Non-resonant 43. Noise that is generated from our galaxy. Ans: galactic noise 44. Electrical noise inherent to a particular device, circuit, or system that remains when no other signal is present. Ans: background noise 45. Which is not a method of data compression? Ans: Winzip 46. Typical ac signal drive for a 19-in. picture tube. Ans: 140 Vp-p 47. This is a requirement for linearity: ? homogeneity ? additivity ? shift invariance ? all of these (Correct Answer)

48. If the bandwidth is 3000 Hz and the S/N ratio of 1024, the expected channel capacity of the line according to Shannon's theorem is about: Ans: 30,000 bps 49. When an antenna is loaded, its physical length remains unchanged but increases the effectiveness of the electrical length. What is (are) the technique(s) used in loading ? Ans: Loading coil 50. Known as the Cellular Mobile Telecommunication System Policy, issued last November 11, 1992. Ans: DOTC Mem. Cir. No. 92-269 COACHING COMMUNICATIONS I SYNCHRONOUS DATA TRANSMISSION Uses the principle of handshaking BIT RATE OF V.22 1200 kbps BIT RATE OF V.90 56 kbps BIT RATE OF V.34 33.6 kbps BIT RATE OF V.32 9.6 kbps BIT RATE OF GPRS 172.22 kbps IS-95 CDMA - bit rate of 1.23 Mbps BLUETOOTH - has data rate of 72 kbps - has ISM freq range of 2.402 2.480 Ghz 802.11b IEEE standard for Wi Fi 525 HORIZONTAL SCANNING LINES number of scanning lines in the raster of the picture tube for NTSC It takes 1.56 microseconds to scan 12.5 pixels It takes 0.125 microseconds to scan 1 pixel

The interfering beat freq 920 Khz is b/w the 3.58 Mhz chroma subcarrier and 4.5 Mhz sound carrier IS-95 CDMA - Has a data rate of 1.23Mbps - uses QPSK (DSSS) N CONNECTOR The connector w/c has the lowest attenuation at UHF START/STOP MODE A mode of transmission used in public data network wherein the data transferred from the source to the network then to the destination using asynchronous data protocol MODAL DISPERSION Is not a cause of coupling mismatch ABSORPTION AND RAYLEIGH SCATTERING Dominant loss mechanism for silica fiber MERIDIANAL Light rays w/c pass through the longitudinal axis of a fiber core CELOTEX Has the highest absorption coefficient for sound waves GLASS Has the best optical characteristics and least loss Rigid metal conduits shall have at least every 3m A shadow mask of a picture tube has 3 cathodes Signals received from satellites exhibit fairly rapid pulse fading effect because the satellite is rotating Reducing the aperture of the camera iris diameter to 1/ (2)1/2 reduces the light to In analog CMTS (AMPS), the narrow band control channel w/c uses 395 duplex voice channels is channel 21 The diagonal screen measurement of 17CPU picture tube is 17in Wireless 3G system can increase its network capacity by 70 percent compared to a lower wireless system 3.5 MHz typical frequency for FM signal in VCR recording PHASE SHIFT KEYING Type of angle modulation wherein the input signal voltage is in digital binary form PRE-EMPHASIS

Limits noise distortion by converting PM to FM LOCAL OSCILLATOR Tunes the channels in the receiver DISCRIMINATOR Used as the 2nd detector of a Doppler radar 2ND ANODE the most positive element in the tv picture tube RADIATION RESISTENCE Equal to radiated power / current2 RADIATION FIELD Field surrounding the antenna w/c does not collapse back into the antenna rather is radiated into space DIRECTIVITY GAIN Direction of gain in one of the major lobes of the radiation pattern NOISE MARGIN Measurement of comparison for amplitude noise characteristics BELL SYSTEMS SELECTIVE CALLING Is an example of asynchronous data protocol EYES AND SKIN Parts of the body w/c are most sensitive to laser PHOSPHORUS Coating in the picture tube that . when struck by an electron beam OSCILLOSCOPE Device used to make a modulated envelope visible CABLE SPLICING AND SIMPLICITY Not an advantage of fiber optics OPTIMUM WORKING FREQUENCY Freq commonly used in sky propagation because of its low loss problem The PCMs biggest disadvantage is its large bandwidth requirement For an SSB transmitter, the average power is 1/4 to 1/3 of the peak envelope power When the distance b/w the source and listener triples, the sound intensity is reduced to 1/9 For a 128 bits Hamming code, n = 8 VLP Uses laser light for playback TYPE 2

A type of cassette type also known as the chrome type VOIP Is a value added service ENHANCED SERVICES Improve the quality and/or functionality of services ordinarily offered by local exchange and inter exchange operators SOLAR CYCLE Repeats every 11 yrs BURST NOISE Another name for pop corn noise HECTOMETRIC WAVES Wavelength of the MF band NYQUIST SAMPLING THEOREM Fs >= 2Famax VOR/DME A ground based navigation system w/c has a center freq of 108 118 MHz BAND STOP FILTER Attenuates a certain freq band but passes frequencies below and above that band 525 HORIZONTAL LINES are developed in the raster of a TV screen in the NTSC standard COMMUNICATIONS II Whenever a conduit enters a box or any enclosure, bashing, shall be provided to protect the wire from abrasion An SSB transmitter has 2 mixers A black and white TV has 2 oscillators Filter method of generating SSB uses 1 balanced modulator HELMHOLTZ RESONATOR A resonant acoustic device consisting of air cavity connected to a larger space by a small opening or neck SOUND PRESSURE FSK A constant amplitude angle modulation wherein the modulating signal is a binary signal that varies b/w two discrete voltage levels rather than a continuously changing analog waveform DIFFERENTIAL PSK

The binary input information is contained in the difference b/w two successive signaling elements rather than the absolute phase DIATONIC An acoustic scale wherein all intervals are constant GENETICS Term in rf radiation w/c refers to damage of cells LOUDNESS Dependent upon the distance b/w the listener and the source PL 259 A UHF connector ERLANG C Traffic model based on the assumption, that calls not immediately satisfied at the first attempt are held in the system until it is satisfied NADIR NUMBER OF LINES ON THE SCREEN Determines the maximum number of vertical picture elements AWG # 19 Commonly used telephone wire WiMAX IEEE 802.16 CONVERTER Divides the character code into several channels CHARACTER SYNCHRONIZATION Type of synchronization wherein the beginning and the end of a character is identified L- BAND Used in navigation, marine communications and aeronautics MPEG-3 Motion Picture Experts Group 1, audio layer 3 An MPEG-4 based video compression uses DiVX A TV picture tube has 2.2 gamma T in 10BASET, refers to the type of cable used When a loop of the PLL is locked, the frequency difference detected by the phase detector is 00 Equalizing pulses pf TV are sent during the vertical blanking

The fundamental frequency of a binary square is 1/2 VHF Freq range used in LOS propagation Q AND I AMPLITUDE Determines the purity of the color HELICAL ANTENNA Can transmit/ receive TEM wave polarized in any direction MODULATION FREQUENCY Determine the rate of freq swing of an FM broadcast transmitter FLUTTER ECHO Consists of a rapid succession of noticeable echoes RIBBON a microphone w/c uses a magnet 50 average maximum data rate of fiber optics 2G BYTES digital communication achievable w/a step index single mode fiber 120 OHMS not a common transmission line impedance JAMES CLERK MAXWELL Electromagnetic radiation QUAM Transmission of 2 separate info signals using 2 AM carriers that have the same freq but are 900 out of phase METAL FILM A resistor w/a flicker noise voltage range of .02 to .2 microvolts RADOME A structure made from a plastic like material that encloses the complete antenna assembly RADIO TELEGRAPHY Uses FSK as its modulation technique FREQUENCY INSTABILITY Disadvantage of a single tube transmitter ANECHOIC ROOM Room wherein the boundaries absorbed effectively the incident sound INFRARED Within the visible freq range GYRO FREQUENCY

The period of the wave freq is equal to the time reqd for one complete revolution about the earths magnetic field axis MICROSTRIP A microwave transmission line that is used with printed circuits What is the frequency of pure tone of sound being used as standard in testing - 1000Hz Another term for BW efficiency - Information Density What is the reference standard test tone normally used when it is indicated as zero dBm When sound wave is converted to electric wave by a microphone, what is the frequency of electric wave - 25-8000Hz Transmission that uses connecting medium as multichannel device - Broadband transmission What formula is used to calculate the overall noise performance of amplifier - Friis Formula A single sideband reduced carrier emission type - R3E Period of single time slot of GSM - TDMA lot structure - 577 Microseconds Perceptible repetition of sound echo Component used to produce AM at very high frequencies Diode Reference Noise temperature in degree Celsius 17 Super frequency high range - 3-30GHz Frequency of color burst - 3.58MHz In Biased function, how many significant sidebands are there in FM if its modulation index is 1.0 3 The time when FET is ON is called acquisition Characteristic of sound related to sonic time pattern Rhythm Period of a visible H race - 53.5 microseconds Does not fall under the optical spectrum - Gamma Rays Advantage of a high level modulated AM transmitter - Higher Value of operating power A cable that uses 100-1000 Mbps ethernet installation uses ____ cable ISTP A double sideband full carrier emission type - A3E

The only Layer existing at night - F2 The normally available chracteristic impedance of coaxial cable are 75 ohms and _____ - 50 Ohms Average absorption for a person - 4.7 sabines In telephony, the M88 loading coil is place with interval of ____ ft - 900 Color subcarrier of channel 5 - 80.83 MHz Microphone that has a Z output Crystal Textcode that uses 16 bit long coded words Unicode Letters and numbers designation of a carrier and a SB - H3E Percentage of primary color of color TV needed to produce the biggest white - 30%red, 59%green, 11%blue In data communications, for FSK, bit rate is _____ to its baud rate equal High Frequencies are - affected by the solar cycle Transmitter power output is single sideband is expressed in terms of PEP Component in Telephone systems whose primary function is to interface the handset to local loop - Induction coil What type of secondary detector is used in AM Diode Ground waves eventually disappears as one moves away from the transmitter, because of ____ = Tilting What refers to the direction of the electric field vectors in space polarization When was the first stowager step by step switched used 1897 What is the fluctuation in signal frequency in the receiver Fading Diffraction of electromagnetic waves - occurs around edges of sharp obstacles Typical PBX configuration is - star topology Antenna which uses the ground as port of its resonant circuit Marconi Most people receive unconscious in sound level of ____ dB - 6-10 The Frequency range of fiber optics system - 100-1000 THz

The wavelength of visible spectrum is in the range of - 0.4 -0.8 microns The signal varies in between 3 levels - bipolar code Stage in broadcast transmitter which is normally class C- modulated amplifier How many pins does a RS 232 have 25 Who first proposed the microwave telephone via satellite - Arthur Clarke Other term for MPEG - 7 - Multimedia Content Description Interface IEEE standard for bluetooth - 802.15 It can be used both recording and playback VHF Ground wave communications is more effective at what frequency range 300 to 3 MHz Any point on the spherical waveform may be a source of a secondary spherical wavefront Huygens Principle Term used for Jitter above 10Hz Wander Boolean function expressed as sum of min terms and product of ax terms are in what form Canonical At very high frequency, transmission lines act as Antenna How many voice channels are there in DS-2 digital signal hierarchy of TDM signals 96 Portions of the tv signal that is used to synchronize the video formation in the recorder tape Vertical Tape Noise measured from tip to ring terminals of a network shall be ____DBRNCO 15 Other term for optical density Radiant Flux Microwave antenna formed from circular waveguide Conical Horn Antenna What causes attenuation in waveguides Walls of the waveguide Measure of threshold of hearing Hearing Level What is a non continuous noise of irregular pulse Jitter Limit of maximum capacity of a channel given a noise level Shannon Hartley Theorem Speed of light in air compared to speed of light in glass is Higher

Modulated system employed by the European cordless telephone GPSK Device that displays state signal of many lines simultaneously Local Analyzer Grounding system of AM broadcast tower radiator can be improve by placing radial wire called Counterpoise In Data communications circuit, synchronous data format is used in _____ synchronization Bit The data signaling channel in cellular system that handles administrative overheads is known as ____ channel Paging How many groups are there in supermaster group 75 Global specification for wireless LAN 802.11b Primary specification of optical fiber cable expressed as loss in dB/Km Attenuation Width of V Blanking pulse 1333 sec Width of H Blanking pulse 10.2 sec Among visible lines of green, blue, yellow, orange, which have the longest wavelength Orange In FSK, the rate of change of frequency at the input of the modulator is _____ - Bit Rate Prevents aural RF from entering the video transmitter and vice versa Diplex Not an application of PLL Am Discriminator GPRS uplink data rate 14 Kbps COMMUNICATIONS 1meter approximate length of ?/2 radiating antenna at 150MHz 13 kbps speech coding rate of GSM 19 kHz pilot subcarrier freq of commercial stereo FM 52sec time duration of 1 horizontal trace in TV 75% - blanking level for negative transmission 800nm wavelength of a light wave of 8000Angstrom AFC purpose help maintain steady LO frequency Noise immunity advantage of digital over analog transmission Will not produce sound in headset connecting directly across the tuner in a simple am radio receiver --- Aspect ratio ratio of screen width with height Ambiphony in acoustics, a method of adjusting reverberation by means of loudspeaker feedback system

B channel an ISDN channel that is projected to carry electronic mails at a transmission rate of 4.8 64kbps Around the tube face makikita ang degaussing coil TDMA most used multiple access system sa Satellite Comms Insufficient picture width effect pag may weak horizontal amplifier Refraction bending of radio wave from high density to low density Refraction - bending of light wave due to change in velocity as a result of traveling from one medium to the other Information capacity no. of independent sidebands that can be carried out through the comm. System Presentation layer that access and structures messages for the application layer Trellis coding use convolutional coding technique Discrete code bar codes are omnipresent black and white striped stickers. Code 39 is an example of --- type of bar code Equal to the Zo of the line if the transmitted power is absorbed by the load, characteristic impedance is --- 0.01micron equal sa 1Angstrom Twice no. of times per second magsend ang mobile station ng requirement report sa BSC 3.58MHz second IF value of color for TV 640 x 480 pixels progressive ibig sabihin ng 480pixel format 5 times as much info ng present NTSC TV ang High definition TV picture Increase of 50% - sa transmitted power pag ang modulation index ay nag vary from 0 to 1 Rest frequency frequency of unmodulated carrier Balanced detector detector na hindi ginagamit sa mobile Resonant frequency of tuner determines the channel 93O to avoid reflection, the load impedance used to terminate RG62 is compared as --- ?/2 vertical antenna antenna used for radiating AM broadcast band Antenna height the recommended 120 radial of AM broadcasting tower and to improve ground conductivity should be equal to --- RF amplifier major element na hindi laging nakikita sa lahat ng superheterodyne FM pre modulation system most noise resistant Midday most ionized ang E region Independent Sideband Emission B8E form of modulation Troposcatter beyond horizon propagation Twice it is 100% modulation, if --- the maximum unmodulated carrier 4 no. of facsimile divisions set by ITU

Luminescence radiation of light in TV picture as it is excited Space division multiplexing oldest and simplest kind of multiplexing Carrier is transmitted if a balance system is not properly balanced, Faradays effect reason why helical antenna are often used for vhf tracking Firewire bus that connects peripheral devices to microcomputer Packet smallest block of data that is transmitted over the network 4MHz guardband between transponder channels for commercial C-band in satellite comms 0.04micron wavelength of violet ray of light 3100 carrier frequency of super group 10 in L600 master group Adding undoped or intrinsic layer between P and N semiconductor to increase sensitivity and response time of photodiode Newton second per cubic meter unit of characteristic impedance Branch circuit capacitors capacitors that are after final overcurrent device and before load served 10-30km maximum distance between repeaters 28dB in catv, the minimum terminals isolation per subscriber 16dB in catv, RF output terminal match in fm 460m Loran position accuracy Bit-oriented protocol achieves code transparency with frequency Sync analyzer not a major component of cooler tv receiver Low pass filter filter used to demodulate PAM signal Ampere per meter SI unit of magnetic field intensity Numerical aperture figure of merit used to measure light gathering or light colleting ability of optical fiber Interface reduction a sound of separation distance between two co-channels and cell radius is known as co-channel --- Lower index of refraction of glass to water is --- Dipole technical equivalent of ?/4 which is open- circuited Attract electrons in the picture tube purpose of large picture tube voltage Nothing in a TV broadcast station that is transmitting but not modulating, a receiver tuned to its frequency hears --- Glass fiber core optical fiber with smallest bandwidth Carrier oscillator BPF of SSB receiver 1 mV maximum output voltage of magnetic microphone 30 GHz largest frequency that can be generated By IMPATT microwave diode oscillator 96 kHz suppressed carrier freq of channel 4 of a group using FDM telephony

F-7 type among connectors and transmission lines for coax, it is the least expensive and widely used for tv, vcrs and catv Two no. of transistors in cmos inverter 16 16kHz audible freq detected by human ear 16:9 aspect ratio of hdtv 70MHz most common IF carrier freq 300 3400 freq range used for telephony 200,000 hours lifetime of LED Distortion and splatter Equal to zero if no power to transmission system, VSWR is --- Phasing method and filter method used for suppressing sideband Cosine MPEG 2 video compression used discrete --- transform algorithm D layer layer that is present in morning only Poke through system where cable and or wires are placed with in ceiling space and poke up through the fire- resistant floor to the next room of office above Bandwidth of tuner determined by the highest frequency component of the modulated signal Greater power gain- advantage of series modulation White noise achieved when correctly terminated but without traffic Knife- edge diffraction when skywave passes over a mountain ridge, a small part of the signal is diffracted down the far end of the mountain Vinton Cerf father of internet 1000 meters optical fiber cable length with lowest attenuation 300,000 holes shadow mask for color tv Limiter in fm, it eliminates variation in amplitude Header raceway of cross section with or first below the floor and transmitter Two - in cmts, the interfering signal strength is approximately --- percent of the desired signal strength to ensure negligible interference 12W maximum instantaneous peak power if pep=6W Four minimum no. of sections of communication systems 290K reference temperature for noise analysis Sabine unit for sound absorption 6.3 heater voltage for tv Celotex highest absorption coefficient for sound wave Foster-Seeley, Quadrature and PLL types of fm demodulators 56 degrees A solid microwave parabolic antenna / reflector maximum axial or thrust force to the wind load occur at a wind angle of --- for normal 600 mV maximum power of Class I telephone system 4.5 MHz frequency separation of positive and negative transmission Velocity factor of transmission lines - 0.9

The most used light source for fiber optic communications injection laser diode Which one is used for optic fiber communications semiconductor laser Which circuit connects the Private branch exchange (PBX) tie trunk In delta modulation which causes the most error in output slope overload What is the figure of merit or modulation degree of FSK h-factor In satellite communications frequency hopping is the same as - CDMA What is multi accessing technique which is transmitted on the same freq and is not limited to any order time using encryption CDMA Which system uses checksum error detection XMODEM An SNA is ____ - Hierarchy topology An OS system in a group of buildings NOVELL system A rapid succession of echos flutter echos Instrument used to measure the height of the ionosphere - ionosonde 1A- 10-10m Light intensity candela Voice channel of mastergroup 600 Pipelining fetching another instruction as soon as the instruction is sent A small distribution - SMATV A system in april 2002 which is for low power consumption low data rates, security called IEEE 802.15.4 - Zigbee Color of combination of weak green weak blue and weak red gray When an overmodulation or distortion occurs and additional sidebands are produced splatter When you pass into a too narrow filter amplifier filter ringing When too load sound weakens or cancels a sound masking Made up of Pb or lead oxide Plumbicon

Persistence effect in which decay is less than __ percent of the maximum value 1 Synchronous modems are more expensive than asynchronous modem because it requires a clock recovery synchronization A transmitted receive clock free running at same speed asynchronous Mpeg 4 is a DIVX Which is the least lagging Plumbicon What is the dark current of Vidicon 0.2 ua What is the decay time of TV picture tube 5ms Anode capacitance of TV picture glass envelope 2000pf Data rate of 3G in a moving vehicle 144kbps GPRS 172.2kbps Data rate of 3G in slow pedestrian 284kbps WiFi data rate 11-56Mbps Wimax theoretical maximum distance 50 km Wimax practical distance 2-5mi Wimax data rate 500kbps 8mbps Antenna in itself self oscillation Hertz Hertz antenna operate above ___ - 2mhz Phase difference of 1/8? antenna 135 degrees Antenna dish that is elliptical in form Gregorian Fed A ribbon microphone is a pressurized granule Out of control oscillation singing What is the voltage drop. To the load 5% Noise generated when signal passes to filter when coefficient or other parameters changes to adapt Zipper noise Links the two host receives and process information session layer Transmission in 10 mbps 100 mbps ISDN Class II cellular power ratings 1.6 watts

WISP wireless internet service provider is used to provide internet access to cafes, hotels, motels operates in 11mbps CDPD (Cellular Digital Packet Data) is the oldest analog cellulartransmission over analog voice channel has a rate 19.2mbps Flicker noise pink noise Flicker noise inversely proportional to frequency In digital system ____ is used in PAM Low pass filter Standard terrestial digital tv transmission 8-V.58 Data rate for terrestial digital tv transmission to provide with sufficient sychronization and error correction - 32.28mbps In telephony, wire used for local loop with 170ohms/100miles AW #22 What single digital network for processing and transmitting SDH Area directly above the vertical antenna curve of silence Used in modem - PSK Maximum current in marconi base Sound heard in a room from another room through the wall flanking Absorption of a man 4.7 sabines Speed of bluetooth technology 72kbps Bit transparency by frequency bisinc Biphase coding coding used for satellite telemetry Protocol which allows for PC pheripherals or other electronic devices to communicate or interoperate SWAP (Standard Wireless access protocol) 108-114mhz- not used by tv has highest directivity with same size parabolic Clarke use of microwave satellite for tv Data rate of SMSI fiber optic- 2GBPS Divx mpeg 4 compression technique Noise on transistors- shot noise CDMA wide bandwidth spread sprectrum using crypted codes

Random spikes of voltages that appear as noise jitter Jitter above 10hz - wander Actual minimum wavelength of antenna one quarter wavelength Characters which are more frequently used have lesser bits Huffman coding Physical and date ling Bridge What is transferring Universal Transverse Acceleration - UTC Optical fiber 800thz 10gbps Ethernet CSMA/CD 10mbps RG-11 is used in thick Ethernet TDM 8kbps IS-95 CDMA 1.23mbps v.22 1200kbps v.90 56kbps 8000 Ix - minimum illumination recommended for reading. scatter angle - in tropospheric scatter propagation, attenuation depends on ___. call lost of 5% - the grade of service is P = 0.05 shading of rf signal by hills and trees - a mobile phone is experiencing a 'dead' area reception due to ___. light is emitted in many directions - not an advantage of planar heterojunction LED over planar diffuse LED. induction field - portion of field energy that does not collapse back to the antenna ans id therefore limited to the zone immediately surrounding the antenna. discriminator - demodulation of sound signal in TV is accomplished by ___. ARQ - error control of high frequency radio data transmission. transmission loss - aka signal reduction index. scanning line - horizontal sync pulse occurs every ___.

X.75 - protocol used to connect after the packet switching network. internet protocol - software that prepares a packet of data yellow - with highest luminance. 10Gbps - data rate in fiber optics. 8kbps - bit rate of TDMA. class X - not a class of laser radiation. 500kpbs to 8Mbps - data rate of WiMax. 2500 ohms - impedance of half-wave antenna at open ends. marconi - antenna used in cars for mobile phones. compressibility - the propagation velocity of longitudinal waves depends on the ___ of the medium. 1.6 - the ERP of class II cellular mobile phone normally used to GSM system is ___ watts. 32 - the electronic serial number (ESN) assigned at the factory of cellular mobile phone has ___ bits. 10 pulse/sec - rate of pulse dialling. local oscillator - circuit that accompanies the mixer. 10.2 microsec - time alloted for horizontal retrace in tv. 300 to 3400 Hz - standard analog tv channel bandwidth. hierarchical topology - typical SNA topology. green - beam that passes straight through (CRT). modulated - 400Hz is transmitted on an AM station operationg at 590Hz; 400Hz is not the ___ freq. 1.3 micron - fiber optic wavelength used because of its attenuation null. product of bit rate and distance - fiber optic performance (is measured as). bandwidth - no sideband - AM transmitter without modulating signal. no noise discrimination - disadvantage of slope detection in FM.

better image rejection - dichroic - mirror that reflects only one light and passes all others. DNI - isothermal - constant temperature system. matrix - combining circuit in TV. IS-95 - uses CDMA. travelling wave tube - microwave tube, linear. peak envelope - output power of SSB is expressed? as ___ power. phon - measure of loudness of time compared to 1kHz tone. crystal radio receiver - first radio receiver. CDMA - in satellite comms, frequency hopping. heterodyning - process of product detection. gray - weak red, weak green, weak blue. flicker - device noise where intensity decreases with frequency. PCM - not a continuous wave modulation. 45.75MHz - IF, TV NTSC standard. notch antenna - open-end slot antenna. intelligibility - measure of info content of speech signal that can be understood correctly. hydrophone - underwater acoustic pressure sensor. mu-law - US standard 1544kbps 24-channel PCS. network layer - layer for end-to-end accountability through network. yellow-green - part of visible spectrum where the camera pickup has the greatest output. radiation pattern - indication of radiated field strength around the antenna. acoustic intensity - acoustic energy flowing per unit (?) measured per unit of time.

concave - must be avoided because this results to undesired focusing of sound. keyed AGC is AGC used in tv receivers. COACHING ELECTRONICS SYSTEMS AND TECHNOLOGIES Shape factor is a measure of _______. SKIRT STEEPNESS Ducts are often formed over ______. BODIES OF WATER A class of bias that produces the least harmonics. CLASS A To raise the power level of AM signals, the class used is ______. CLASS A SSB modulation is classified as. AM What will a normal AM receiver detect in an unmodulated RF AC wave? NOTHING New access for 3G mobile telephony. WCDMA In a single-gun color CRT, what electron beam travels straight through the tube? GREEN The person who laid out the theory of acoustics for buildings. W.C. SABINE The number of scanned lines per frame in the raster on the picture tube. 525 The time the FET in on. ACQUISITION The advantage of a high level AM modulator is. HIGHER LEVEL OF OPERATING POWER The letter and number designation of a carrier and a single side band. H3E Uses the principle of handshaking. SYNCHRONOUS DATA TRANSMISSION The bit rate of V.22. 1200 Kbps The bit rate of V.90. 56 Kbps The bit rate of V.34. 33.6 Kbps The bit rate of V.32. 9.6 Kbps The bit rate of GPRS. 172.22 Kbps IS-95 CDMA has a bit rate of. 1.23 Mbps

The date rate of Bluetooth is ______. 72 Kbps Bluetooth has an ISM frequency range of ______. 2.402 2.480 GHz IEEE standard for Wi-Fi. 802.11b It takes ______ to scan 12.5 pixels. 1.56 MICROSECONDS It takes ______ to scan 1 pixel. 0.125 s The interfering beat frequency 920 KHz is between the 3.58 MHz chroma subcarrier and 4.5 MHz sound carrier The average absorption of a person is ______. 4.7 SABINES MEDIAN The most common light generator in fiber optics. INJECTION LASER DIODE The brightness of light source is called its luminous intensity, whose unit is. CANDELA An instrument for measuring the layer in the ionosphere used for wave propagation. IONOSONDE Instrument that normally measures the virtual height of ionosphere. IONOSONDE The cause of attenuation in microwave guides. GUIDE WALLS Typical IF frequency. 70MHz Not a typical line impedance. 120 O The most common and most affordable cable connector. F-7 Filter used for demodulating PAM. LPF Made of plastic and is used to protect the antenna assembly from wind and snow loading. RADOME What does MP3 mean? MOTION PICTURE EXPERTS GROUP 1, AUDIO LAYER 3 Number of mixers in a SSB receiver. 2 High frequency transmission lines act as a ______. ANTENNA Measure of loudness; equal to 40 phons. SONE A room which absorbs efficiently all incident sound wave. ANECHOIC ROOM

An ______ chamber is often used to test microwave antennas. ANECHOIC CHAMBER Commonly used for subscriber loop design. AWG # 19 UHF connector PL-259 Who profounded electromagnetic radiation theory? JAMES CLERK MAXWELL The aspect ratio of HDTV is. 16:9 The unit of magnetic field intensity. AMPERE / METER Uses checksum as an error detection system. XMODEM Unit of sound absorption. SABINES KNIFE EDGE DIFFRACTION A device that prevents aural RF to mix with the video. DIPLEXER What is the lifetime of LEDs? 200,000 HOURS What is the lifetime of ILDs? 50,000 HOURS The characteristic impedance of coaxial cables are usually available in 75O and 50 ? The minimum illumination recommended for reading is ______. 800 lx The quality in sound that corresponds to color in light. PITCH It is not a continuous wave modulation. PULSE CODE MODULATION (PCM) Who founded the wave theory of light? CHRISTIAN HUYGEN A large emission of hydrogen from the sun that effects communications. SOLAR FLARES The solar cycle repeats the period of great electrical disturbance approximately every ______. 11 YEARS What sound characteristic relates to sonic time pattern? RHYTHM What do you call the perceptible sound repetition? ECHO What theorem set a limit on the maximum capacity of a channel w/ a given noise level? SHANNON-HARTLEY THEOREM What does NIF stand for? NOISE IMPROVEMENT FACTOR The third symbol of emission is ______.

THE TYPE OF INFORMATION TO BE TRANSMITTED Single Sideband Reduced Carrier. R3E The ITU designation for Double Sideband Full Carrier. A3E The ideal time for trans-equatorial signal propagation. AFTERNOON AND EARLY EVENING Each point on a spherical waveform maybe a source of a secondary spherical wavefront. HUYGENS PRINCIPLE A component in the telephone set that has the primary function of compensating for the local loop length. VARISTOR Shadow mask for TV has approximately ______ holes. 300,000 The type of core used in PCS fiber. GLASS Which of the following is used as a high-power microwave oscillator? MAGNETRON Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction? ISOLATOR The smallest beam of a satellite antenna radiation pattern. SPOT BEAM A satellite beam that covers almost 42.4% of the earths surface. GLOBAL BEAM Fiber optic cables operate at frequencies near ______. 800 THz Distortion enhances intelligibility when an __________ is added. EXCITER Consists of a rapid succession of noticeable echoes. FLUTTER ECHO The type of emission that suffer most from selective fading. FM AND DOUBLE SIDEBAND AM Which component is used to produce AM at very high frequencies? PIN DIODE ______ is measured on a circuit when it is correctly terminated but does not have any traffic. WHITE NOISE What is the amount of sound reduction provided by barriers, wall, floor, or ceiling, called? TRANSMISSION LOSS What is the velocity of sound in wood? 3300 m / s Which of the following is NOT an acoustical defect to be avoided in acoustical designs? REVERBERATION

What is the term used to describe a spread spectrum communications system where the center frequencies of a conventional carrier is altered many times per second in accordance w/ a pseudo-random list of channels? FREQUENCY HOPPING In cellular system, the average lead time to install a new base station is approximately? 6 MONTHS TO 1 YEAR At one atmospheric pressure, what is the approx speed of sound in steel? 5150 m / s Atmospheric attenuation is due to ______. WATER VAPOR AND OXYGEN Satellite orbits around the earth are ______ orbits. ELLIPTICAL OR CIRCULAR What is affected by the distance between the listener and the source of the sound because the intensity varies inversely with the square of the distance? LOUDNESS Comparing the capacities of a DVD and an ordinary CD, DVD is ______ times bigger than CD. 5 TIMES What causes MUF to vary? THE AMOUNT OF RADIATION RECEIVED FROM THE SUN Impedance matching ratio of coaxial balun. 4:1 A continuous tone generated by the combination of frequencies 350Hz to 440Hz used in telephone sets. CALL WAITING TONE A component in the telephone set that has the primary function of interfacing the handset to the local loop. INDUCTION COIL A telephone wire that connects 2 central offices. TRUNK LINE A special service circuit connecting 2 private branch exchanges (PBX). TIE TRUNK When was the 1st Strowger step-by-step switch used? 1897 The first symbol of emission is. THE TYPE OF MODULATION OF THE MAIN CARRIER The second symbol of emission is. THE NATURE OF SIGNALS MODULATING THE MAIN CARRIER The maximum ground resistance in an equipment installation as required by Volume 1 of the Philippine Electronic Code (Safety Code) is ______. 5 O One of the reasons why FDM is being replaced by TDM is ______. NOISE IS AMPLIFIED WITH VOICE WHEN FDM IS USED

What kind of receiver is used in conventional telephone handset? ELECTROMAGNETIC Low-power radar uses ______. IMPATT Code widely used for compression in which the most commonly used characters contain the fewest bits and the less commonly used characters contain the most bits. It is a source code whose average word length approaches the fundamental limit set by the entropy of a discrete memoryless source. HUFFMAN CODE OR CODING The allowable deviation ratio of commercial FM broadcast. 5 What frequencies do oxygen cause excessive attenuation? 60 GHz What is the signal-to-noise ratio required for satisfactory telephone service? 50 dB The use of telecommunication for automatic indicating or recording measurement at the distance from the measuring instrument. TELEMETRY What consists the front-end circuit of a VHF TV superheterodyne receiver? LOCAL OSCILLATOR, MIXER AND RF AMPLIFIER What satellite subsystem monitors onboard conditions such as temperature and battery voltage and transmits this data to a ground station for analysis? TTC What is the typical center frequency spacing between adjacent channels in satellites? 40 MHz What material is most often used for the outer covering of coaxial cables? PVC Defined as a figure of merit used to express the degree of modulation achieved in an FSK modulator. H FACTOR Which is considered as the fastest LAN topology? BUS What is the other name for parity? VRC What ferrite device can be used instead of duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna? CIRCULATOR 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. 5 MILS A mechanism or device which enables the TV camera to move in lateral and tilting motion. PAN / TILT DEVICE The time duration for one horizontal trace. 52 s

Tropospheric scatter is a method of sky wave propagation for which of the following frequency bands? 300 MHz TO 3 GHz The antenna effective height is ______ of the actual height. - What is the end impedance of a half wave dipole? 2500 ? Impedance of the half wave dipole. 73 ohms What device measures the angle between 2 radio frequencies and also the direction of propagation of a wave? GONIOMETER The american concert pitch A is equivalent to _____. 440 Hz The international pitch A is equivalent to ______. 435 Hz Which standard recommends crosstalk limits? CCITT G. 151 Which standard is utilized in intermodulation noise rates on PCM audio channels? CCITT REC. G. 172 What is the reference frequency of CCITT phosphometric noise measurement? 800 Hz A range of microwave frequencies more easily passed by the atmosphere than are the others is called a ______. WINDOW Tropospheric scatter is used with frequencies in the following range. UHF The ground wave eventually disappears as one moves away from the transmitter, because of ______. TILTING In testing a transmitter, to prevent interfering with other stations, which type of antenna must be used? DUMMY ANTENNA Typical speech power. 10 TO 1000 MICROWATTS Cellular phones transmit in the band from ______. 825 TO 845 MHz Cellular phones receive in the band from ______. 870 TO 890 MHz The range of a cellular CDMA system in miles. 13 MILES SYN character of EBCDIC code. 32 H What are the steps to follow to produce a PCM signal? SAMPLING, QUANTIZING AND CODING A type of transmission wherein data are inputted directly on the cable. BASEBAND TRANSMISSION

A network operating system within several building in compound. NOVELL NETWARE What is the dielectric constant of PE insulator? 2.27 What is the typical velocity factor of an open-wire transmission line? 0.9 What is the typical velocity factor of a twin-lead line? 0.8 Which does not fall under the optical spectrum? GAMMA RAYS In telephony, if the grade of service of your telephone connection indicates 0.05, what does that mean? 5% LOST CALLS The unit of pitch. MEL Which major component cannot be found in all superheterodyne receivers? RF AMPLIFIERS Used to solve overall noise figure. FRIIS FORMULA Reference noise temperature. 17oC or 290 K Propagation beyond the horizon. TROPOSCATTER Instrument used to view the envelope of an AM wave. OSCILLOSCOPE Used to make a modulated envelope visible. OSCILLOSCOPE Component in FM receiver that removes amplitude variations or rids FM noise. LIMITER Frequency band used for transmission by submarines. ELF The current in a Marconi antenna is maximum at the ______. BASE Caused by transverse nature of electromagnetic waves. POLARIZATION Layer where the transmission of bits or data happens & provides no detection error. PHYSICAL LAYER Pre-modulation system most immune to noise. FM Another name for popcorn noise. BURST NOISE Another name for pink noise. FLICKER NOISE Example or consists of parasitic arrays. YAGI-UDA Consists of arrays of dipoles in same phase from the source. BROADSIDE ARRAY

A 3G wireless system can increase its network capacity by ____ as compared to lower generation wireless system. 70% The ability to work properly in presence of strong signal outside the band of interest. BLOCKING DYNAMIC RANGE A voice band of 400 Hz is to be transmitted in an AM transmitter operating at 590 KHz. The 400 Hz voice band is not the ______ signal. MODULATING The ability to retain the original number and services when moving to new location. LOCAL NUMBER PORTABILITY An open-ended slot antenna. NOTCH Not an advantage of planar heterojunction LED over planar diffusion LED. TEMPERATURE DEPENDENT Transequatorial propagation is best propagated during ____. AFTERNOON or EARLY EVENING E-LAYER The 2nd detector of AM. DIODE Doppler radar uses _____ as 2nd detector. DISCRIMINATOR Proposed the use of microwave phone by satellite. ARTHUR CLARKE All power is absorbed when load impedance is equal to ______. ZL 120 radials equal to. ANTENNA HEIGHT Test tone signal. 1000Hz Reference tone level for dBa of F1A noise unit. -85 dBm 1000 Hz at ____ above listeners threshold of hearing in loudness. 40 dB A voice operated device that inserts a high loss in the opposite direction of transmission of the talking party. ECHO SUPRESSOR Uncontrolled echo. SINGING ?/2, 150 MHz = 1m LENGTH Max. critical value of incident angle which light propagates through the fiber. ACCEPTANCE ANGLE Microphone that produces z output. CRYSTAL MICROPHONE

Used to measure underwater sound pressure. HYDROPHONE Movement of light wave form lower density to higher density medium. REFRACTION Bending of light waves. REFRACTION Introduction of a parity bit for error detection does not necessarily mean. AUTOMATIC ERROR DETECTION Who is the father of internet? VINTON CERF Minimum number of sections required for communications receiver. 4 What is produced by weak red, weak blue and weak green in the CRT. GRAY Supports cables. CABLE TRAY IEEE global standard for wireless LAN. 802.11b Modulation technique used for European Cordless Telephone. GFSK Uplink data rate for GPRS. 14 kbps Not a function of PLL. AM DISCRIMINATOR Among the colors blue, yellow, green and orange, which has the longest wavelength? ORANGE In April 2002, IEEE published its 802.16 standard for Broadband Wireless Access also known as? Wi-MAX A figure of merit which refers to the light collecting or gathering ability of optical fibers. NUMERICAL APERTURE The ______ is the sine of the angle of acceptance. NUMERICAL APERTURE An effect that occurs in the ear where a louder sound can reduce or even stop the nerve voltage generated by a weaker sound. MASKING The signal where the receiver response of 2.4kHz in the IF circuitry is optimum? SSB VOICE Audible frequency of the human ear. 16 Hz 16 KHz How many mixers are there in a SSB receiver? 2 How many oscillators are there in a black and white TV receiver? 2 How many transistors are there in a CMOS inverter? 2 The sound channel spacing between two co-channel cells and the cell radius. INTERFACE REDUCTION

Difference between co-radial channels within the same radius INTERFACE REDUCTION SATELLITE CLOSET The modulation technique where the modulated wave is always present. CONTINUOUS MODULATION Frequency in the channel 4 group in FDM telephony. 96 KHz The width of a V blanking signal. 1333 s The width of a H blanking signal. 10.2 s The wavelength where there is attenuation null? 1.3 MICRONS Camera tube which uses Lead Oxide (PbO)? PLUMBICON An acoustic resonant cavity resonator where the air cavity is connected to a larger space by a relatively small opening or necking. HELMHOLTZ RESONATOR IS-95 In satellite communications, frequency hopping is a form of ______. CDMA The frequency range most effective for LOS propagation. VHF Mirror which reflects one color and passes all the other colors. DICHROIC Acoustic Interval where the intervals are exactly constant. DIATONIC IEEE 802.15.4 also known as. ZIGBEE The process required for product detection. HETERODYNING SERIES MODULATION Antenna with TEM radiated in all directions. HELICAL ANTENNA The ratio of the reflected voltage to the forward traveling voltage. REFLECTION COEFFICIENT MPEG-4 is also known as ____. DIVX Most common modulation technique used in radio telegraphy. FSK FEC Groundwave communications is used in what frequency range? 300 KHz 3 MHz

What layer of the ionosphere absorbs medium frequency and reflects high frequency? D LAYER A colloquial term for non-continuous noise of irregular pulses or spikes of short duration with high amplitudes. JITTER A colloquial term when there is overmodulation. SPLATTER Jitter above 10 Hz. WANDER They are caused by over modulation. DISTORTION AND SPLATTER When too high signals enter the modulator. DISTORTION AND SPLATTER Data signaling channel in cellular system that handles administrative overhead. PAGING Filter needed to demodulate PAM signals. LOW PASS FILTER The capacity of an optical fiber is often measured by. THE PRODUCT OF THE BIT RATE AND DISTANCE Wires.. pokes through.. POKE THROUGH To prevent the aural information from entering the video information and vice versa. DIPLEXER GPS has an orbit inclination of ___ with respect to equatorial plane. 55 A transmission line at very high frequencies act as an ______. ANTENNA Measures the relative height of an ionosphere layer. IONOSONDE Three most common demodulators. FOSTER-SEELEY, QUADRATURE, PLL Occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a receiver. FILTER RINGING What determines the selectivity of a receiver? BANDWIDTH OF THE TUNED CIRCUIT The color phasor has what place with respect to the I signal? 57 The maximum data rate of optical fibers. 50 MPEG2 video compression uses discrete ______ transform algorithm. COSINE Synchronization where the beginning and the end of characters are indicated.. CHARACTER SYNCHRONIZATION

The output of a SSB transmitter is usually given as ______ power. PEAK ENVELOPE POWER TV transmission designed for small communities. SMATV Small system that transmits direct to home TV signals. SMATV Microphone that uses a permanent magnet. RIBBON Uses handshaking. DELTA MODULATION Why is synchronous transfer mode more costly than asynchronous transfer mode? BECAUSE IT MAINTAINS A CLOCK RECOVERY CIRCUIT DIFFERENTIAL PHASE SHIFT KEYING GYRO Displays set of lines. LOCAL ANALYZER What is the advantage of the use of high IF? BETTER IMAGE FREQUENCY REJECTION Point between a point and the equator, where it is closer to the point than the equator. NADIR Most common IF. 70 MHz It is also known as optical density. RADIANT FLUX How many beams leave the electron gun in a single-gun CRT? 3 In synchronous (ATU) well ____ . source.. destination VIRTUAL CHANNEL IDENTIFIER What happens when an AM transmitter sends without modulating? NO SIDEBANDS Commonly given in dB / km. ATTENUATION Distance with lowest attenuation. 1000 Km PHON The AM detector performs two basic functions. RECTIFIES & FILTERS ... conduit BASHING Based on assumption that calls not immediately satisfied at first attempt are held in the system until satisfied. ERLANG C If no power, VSWR is equal to ____. ZERO Channel bandwidth of a standard analogue telephone system. 300-3400 Hz For marine & aeronautical communications. L BAND

A radial wire used for improving grounding tower of AM. COUNTERPOISE An antenna array with linear arrangement of diodes 90 out of phase. END-FIRE ARRAY IMPATT diode. 300,000 GHz Mostly used coax cable. F-7 TYPE n of glass is ___ than n of water. LOWER What can you hear from a radio transmitting station without modulation over radio receiver tuned to the same frequency? NOTHING Used in AM broadcast. ?/2 ANTENNA Why do we need a larger voltage in the picture tube? ATTRACTS ELECTRON ON THE FACE OF THE TUBE Uses CDMA. ISDN Rate of RS-232 C. 20kbps Rf-radiation on tissue or reproductive system. GENETIC 1st radio receiver. CRYSTAL BFO. CARRIER OSCILLATOR Output voltage of magnetic microphone. 1 mV Antenna formed from circular waveguide. CONICAL HORN ANTENNA Heater voltage of picture tube. 6.3V Divides characters into several channels & in a slower rate. CONVERTER Standard IF of NTSC TV. 45.75 MHz Most reliable error checking. CRC Layer that is only present during daytime. D-LAYER An antenna with ?/4 when open circuited. DIPOLE Has the highest absorption. CELOTEX Most common cause of distortion in Delta modulation. SLOPE OVERLOAD Noise in resistors & transistors in a circuit. SHOT NOISE Decreases with decrease in frequency. FLICKER NOISE A resistor with flicker noise voltage between 0.02 to 0.20uV. METAL FILM Isolates the oscillator from the load. BUFFER

Has the lowest beamwidth. GLASS CORE . is ___ percent of the max value known as screen persistence. ONE DS-2. 92 Master group. 600 Speed of light in air is ___ than in glass. HIGHER Rate of digital communication that is achievable by Single Mode Step Index. 2 Gbytes SNA topology is also known as ____. HIERARCHY TOPOLOGY PLL locked. 0 HARMONIC RADIATOR SEMICONDUCTOR LASER CRYOGENIC QUAM DNI Formula. 2n = f2 /f1 ; where n= no. of octaves and f1= lower frequency Formula. T=(360TD)/T; where TD=1.016(v?r)(length) & T=1/f Formula. Max. Data rate = 1 / 5Dd where D=distance in km & d=dissipation factor Formula. (S+N)/N in dB =10 log (higher dB/ lower dB) Formula for half power beamwidth. ?=142/vG Formula. f=fo + fo k(T1-To) Output of sideband power. PEP 395 duplex voice channels. CHANNEL 21 Time period for visible lines (H). 53.5us Part of the parabolic that rotates constantly. CAPSTAN Uses the ground as part of the resonant circuit. MARCONI ANTENNA Connector that has the lowest attenuation at UHF. N-TYPE CONNECTOR Most luminescent. YELLOW Radiated power divided by square of current equals ____. RADIATION RESISTANCE

Assuming same size, antenna that has the highest or best gain. PARABOLIC ANTENNA A parabolic antenna is fed by an isotropic source BACKLOBE RADIATION Makes packet of data. INTERNET PROTOCOL FM pilot carrier. 19 kHz Layer where the sending and receiving/interhosting happens. SESSION LAYER Uses bridge. PHYSICAL & DATA LINK Accepts and makes the structure of the data. PRESENTATION LAYER Transmission of sound to an adjacent room through common walls, ceilings, floors. FLANKING TRANSMISSION Most commonly used today. TDM Start of use of GPS. 1978 The area directly above the vertical antenna. CURVE OF SILENCE Meaning of DSSS. DIRECT or DISCRETE SEQUENCE SPREAD SPECTRUM Meaning of CDPD. CELLULAR DIGITAL PACKET DATA Rate or speed of CDPD in kbps. 19.2 Picture tube which has the minimum lag. PLUMBICON Rate of Fiber optic. 10 GHz Rate of Fiber optic. 100-1000THz Convolutional code. TRELLIS TECHNIQUE Is an example of pressure-gradient microphone? RIBBON MICROPHONE Study of walls. AMBIPHONY Movement of signal from one frequency to another by use of mixer-oscillator combination. FREQUENCY TRANSLATION Incoming light is partially absorbed and partially transmitted equally in all direction. LAMBERTIAN REFLECTION AFC used in radio transmitter. KEYED-AFC RG-11 is used in___. THICK ETHERNET Most dense layer. F2 LAYER Layer E is most ionized during___. MIDDAY

Why is companding used in PCM? TO PROTECT SMALL SIGNALS FROM QUANTIZED DISTORTION. SHARED WIRED ACCESS PROTOCOL Another name for MPEG-7. MULTIMEDIA CONTENT DESCRIPTION INTERFACE Universal Transverse Acceleration. UTC Field which does not collapse back to the antenna and is limited to the zone immediately surrounding the antenna. INDUCTION FIELD RADIATION FIELD 1/10? antenna. ELEMENTARY DOUBLET Max. anode capacitance of a TV receiver CRT or picture tube. 2000pF No. of cathodes in a shadow. 3 Antenna in itself that uses ground as part of the resonant circuit and provides self-oscillation. HERTZ ANTENNA Hertz antenna is best used above ____. 2MHz 3G bit rate for slowly moving pedestrian. 384 kbps 3G bit rate for fast-moving vehicles. 144kbps 3G bit rate for mobile or stationary. 2Mbps Disadvantage of plastic fiber over glass fiber. HIGH ATTENUATION In ATM (Asynchronous Transfer Mode), a byte is called ____. OCTET The resolution of a picture is determined in a TV receiver by _____. THE FREQUENCY RESPONSE OF THE VIDEO SIGNAL Complex value which is a ratio of pressure amplitude to the amplitude of the volume velocity. ACOUSTIC IMPEDANCE Has the lowest reflection and is the best compared to other cores. GLASS CORE Theoretical distance of WiMax. 50 km? Max. theoretical distance of wifi. 500 km? Distance of wifi? or WiMax?. 3-5 mi. Bit rate of wifi. 11-54 Mbps Insertion due to path of flow energy. INSERTION LOSS U600 FDM bandwidth. 2520kHz

M88 (88mH) is spaced ___ apart. 9000 ft Wifi or high speed wireless Ethernet IEEE. 801.11 or 802.11b IEEE standard for bluetooth. 802.15 Electronic Serial No. 32 bits Most in camera. YELLOW GREEN Ratio of screen width to its length. ASPECT RATIO Connected after mixer. LOCAL OSCILLATOR Used for playback & recording. VHF Exposed wiring. OPEN WIRE INSULATION Rays that passes through the longitudinal axis. MERIDIANAL Most common configuration of PBX. STAR TOPOLOGY L600. 3100? Operates 108-118 MHz. DME/VOR What is the position accuracy of Loran CD navigation system? 460 m Single sideband full carrier. H3E Independent sideband. B8E Single sideband suppressed carrier. J3E Minimum actual antenna height required for communication. QUARTER WAVELENGTH In antenna reception pattern it is a point with very low signal strength. NULL Color subcarrier for channel 5. 80.83 MHz Used to convert PM to FM. PRE-EMPAHSIS The interfering beat frequency of 820 kHz is between 3.58 MHz color sub carrier and ____. 4.5 MHz INTER CARRIER SOUND Modulation in digital data. QPSK (DSS) Lowest attenuation & highest optical property. GLASS Not included in TV spectrum or range of frequencies. 88-114 or 88-174 MHz? Measure of the half power points of the antennas radiation patterns. BEAMWIDTH

Rotating the plane of polarization of a wavefront by passing it through a ferrite device. FARADAY ROTATION Helical antennas are often used for satellite tracking at VHF because of the FARADAY EFFECT What unit of characteristic impedance is used in acoustics. NEWTON-SECOND PER CUBIC METER Facsimile standard is set by ITU and divided into how many basic groups? 4 In analog CMTS, the interfering signal strength remains approximately less than _____ percent of the desired signal strength to ensure negligible interference. 2 The actual data rate for terrestrial digital TV transmission, to allow for the addition of synchronizing & error-correction. 64 Mbps Oldest and simplest form of multiplexing. SPACE-DIVISION MULTIPLEXING Reflection of sound even after the source is stopped. REVERBERATION Surface that should be avoided because it tends to scatter the sounds. CONCAVE cavity that FREQUENCY METER Which is the most positive element in electron gun of television? 2nd ANODE Probable cause of fading. SHADOW BY HILLS & MOUNTAINS? Can happen near the edge of sharp surfaces. FADING Class C. MODULATED AMPLIFIER Range of industrial noise frequency. 15 to 160MHz Number of pins of RS-232-C. 25 Cellular CDMA BW. 1.23MHz Discrete code. CODE 39 Modem uses ___. PSK Antenna section that is a complete antenna. BAY A word in telegraphy consists of ____ character. 7 dBa above ____. 1uV/m Reference for 0 level. dBm When the distance is tripled the sound intensity is reduced by ___. 1/9

Lowest layer of the atmosphere in HF propagation. C LAYER What are the two main characteristics of sound waves? PITCH AND LOUNDNESS Which is not an advantage of fiber optics? CABLE SPLICING and SIMPLICITY Disadvantage of PCM. REQUIRES LARGER BANDWIDTH Operating frequency of LMDS. 27-31 GHz Responsible for end-to-end transmission. TRANSPORT LAYER Used in Thin Ethernet. RG-58 Violet light wavelength. 0.4-0.8 microns Recurrent PERIODIC DUTY Anode dark current of the CRT. 2uA Where people experience unconscious hearing. 6-10dB Has 3600 voice channels. JUMBO GROUP Has no bottlenecks. MESH TOPOLOGY Transmission from sound to network to destination. START/STOP MODE Sound energy level measured per unit per time. ACOUSTIC INTENSITY carrier of 64B CHANNEL Combination of transmitter and receiver in a rotating satellite. DESPUN As the light goes from air to the ionosphere, its index of refraction. INCREASES ??? is also called____ & is the total amount of information that can be transmitted. INFORMATION DENSITY Electromagnetic waves in travelling ion free space. TEM FM. REST FREQUENCY Device in receiver to reduce impulse noise. NOISE BLANKER Reduction of receiver gain caused by the signal of a nearby station transmitter in the same frequency band. DESENSITIZING Block calls condition specified the held probability at a time period equal to an average holding time. POISSON

Circuit that performs inverse mapping & delivers to the user destination, a reproduction of the original digital source input. SOURCE CODING Protocol used to connect the other packet switching network. X.75 Negative in TV. 25% Error control used in high frequency radio data transmission. ARQ A switching system that lets a large number of telephone or data processing subscribers use a lesser number of transmission lines or a narrower bandwidth. CONCENTRATOR A transmission where data are inputted directly on the cable. BASEBAND Radiation of light from the screen of a TV picture tube as it is evicted. LUMINISCENCE What is the typical frequency for the FM luminance signal in VCR recording? 1.5 MHz What is the guardband between transponder channels in the commercial C-band for satellite communications? 4 MHz What happens to balance modulation if it is not properly balanced? THE CARRIER IS TRANSMITTED What is the firm for a bus that contains peripheral devices such as wireless modems and high speed digital video cameras in a microcomputer? FIREWIRE White. 30% red 59%green 11% blue NOISE FIGURE DECREASED BY 3DB NEAR-END REGION INTELLIGIBILITY 15% less than the Maximum Usable Frequency. OPTIMUM WORKING FREQUENCY AWG #22 1V/secondary PROBABILITY OF ERROR STACK 577us DIRECTIVITY GAIN ENHANCED SERVICE GREGORIAN-FED

BIT LEVEL CODE BIT-ORIENTED PROTOCOL UNICODE AQUADAG 1 Angstrom=. 10-10 m Degaussing coil in TV set is located _____. AROUND THE PICTURE TUBE It is 100% modulated if _____ the maximum unmodulated carrier. TWICE In cellular system, what brief control messages instruct the mobile telephone to tune to a new channel? HANDOFF MESSAGES In CATV system, what is the RF output ??? ??? ? 16 dB In cable TV system, what is the maximum ??? ??? provided each subscriber? 24 dB What determines the station that will be selected by the tuner? RESONANT FREQUENCY OF TUNER The ratio between the energy absorbed by a surface to the total energy absorbed by the surface. ABSORPTION COEFFICIENT A fiber optic light electron PIN diode is lightly doped in _____ material. INTRINSIC Which parts of the body are most sensitive to laser? EYES AND SKIN What is the dominant loss ??? in silicon fiber cable in fiber optics? ABSORPTION AND RAYLEIGH SCATTERING What filter attenuates signals, passes below and above that band? BAND STOP FILTER Bell Systems ???, ??? system is an example of ____. ASYNCHRONOUS DATA PROTOCOL Form of angle modulation constant envelope, digital modulation, wherein the input voltage used is binary digital signal. PHASE SHIFT KEYING Making the aperture of a camera lens smaller by stopping down the iris to diameter of v2 reduces light by ____. HALF