Comms Coaching•

ISDN basic rateAns: 2B+2D

Access B data rateAns: 64 kbps

Maximum diameter of fiberAns: rmax = 0.383λ NA

V numberAns: V = πdNA λo

Neutralization isAns: Elimination of RF signals

An IC of differential amplifier and on-chipAns: NE602

Distance of microwave repeater of fiber opticAns: 6.215 – 18.65 mi

IF up and down converterAns: 70 MHz

Height of GLONASSAns: 19100 km

Accuracy of GPSAns: 2 nautical miles

Phase shiftAns: β = √(ωδu/2)

Negative transmission, medium grayAns: 40%

Negative transmission, tip of syncAns: 100%

1

Comms Coaching•

Negative transmission, blanking levelAns: 75%

Negative transmission, blackAns: 67.5%

Negative transmission, maximum whiteAns: 12.5%

Time for horizontal retraceAns: 10.2 us

Path of telephone line crossing a private property and entering a buildingAns: Service entrance

Cable within a building of series of buildingsAns: Building cable

Circular passage of cableAns: Pipe sleeve

Marine radar communicationsAns: X-band

Civil aircraftAns: 30-100 MHz

Aircraft long range communicationsAns: 2 – 30 MHz

Wireless telegraphAns: 1895v

TelegraphAns: 1844

TelephoneAns: 1876

RadioAns: 1887

2

Comms Coaching•

Average splice of fiber opticAns: 0.15 dB

Pilot subcarrier frequencyAns: 19 kHz

A subcarrier set by musicAns: 67 kHz

Travelling wave antennaAns: Rhombic antenna

Brightness or illuminationAns: contrast

Amplitude of the signalAns: Contrast

Out of controlAns: Singing

Frequency above 300 GHzAns: millimeter waves

Micrwave operatesAns: above 1 GHz

Emits heat energyAns: Infrared

A regulatory body whose sole purpose is allocating spectrum space, issuing licenses, setting standards and policing the airwaves.Ans: FCC

Government and military communications are coordinated by ___Ans: NTIA

The electromagnetic spectrum is managed byAns: ITU

Characteristic impedance of coaxial cable3

Comms Coaching•

Ans: 75 Ω

TDM usedAns: PCM

Telemetry dataAns: PCM

Frequency difference of color subcarrier and soundAns: 0.92 MHz

Chroma signalAns: 3.58 MHz

LORAN C frequencyAns: 100 kHz

Which cannot be used for range and bearing?Ans: LORAN C

Ceramic resonator at frequency of 200 – 500 kHzAns: Ceramic filter

Multiple resonant diskAns: Mechanical bandpass filter

Doubley balanced modulators and GaAs filters are best mixers forAns: VHF, UHF and microwave

Layer of ionosphere for nighttime communicationsAns: F layer

Which of the following is true?Ans: Negative polarity has an amplitude decreases when white.

Third letterAns: Type of information to be transmitted

Lock rangeAns: PLL

Critical part of FM receiver4

Comms Coaching•

Ans: Front end

Advantage of superheterodyne receiverAns: excellent sensitivity and stability

Disadvantage of TRFAns: Tuning and selectivity

Ch.4 downlink frequencyAns: 3.84 MHz

λ/4 vertical λ/4 spaced and 90 degrees out of phaseAns: Unidirectional Cardioid

Discone antenna usesAns: Vertical polarization

No gain antennaAns: Isotropic

Token passing Ans: IEEE 804.2

PLL consists ofAns: FM synthesizer and FM demodulator

Simplest AM receiverAns: TRF

MF rangeAns: 300 kHz- 3 MHz

1 pixelAns: 0.125 us

Folded dipole is ___ the feedpoint of a dipole.Ans: 4

Resonant frequency tuned to the resonant circuit tuned to the multiple input of the signalAns: Frequency multiplier

5

Comms Coaching•

Time constant for pre-emphasis and de-emphasis networkAns: 75 us

To compress voice signal dynamic rangeAns: Companding

Amplifier for PCMAns: Sample and Hold circuit

Cut offAns: Class B

90 degrees to 150 degreesAns: Class C

Benefits of multiplexingAns: Economy

TV picture tube Ans: kinescope

Phase angle in TVAns: hue

Linear amplifierAns: Class A

Transmission rangeAns: TR = (2h)/(tan β)

Frequency of reverberation chamber Ans: f = 125 3√(180/V)

Advantage of FM over AMAns: Noise immunity

Disadvantage of FMAns: Wider bandwidth

Floor area within a building that is usable and rentable6

Comms Coaching•

Ans: Rentable Floor Area

Code for touch tone dialingAns: two-to-seven

Increasing the amplitude level of higher frequency on modulating frequencyAns: Pre-emphasis network

Cable that is entering the buildingAns: Entrance Cable

Comprises of telephone equipment; transmitter/receiver, etc.Ans: Station.

A telephone line that do not serve exchangeAns: Private Line

It is used to connect private branch exchange and central officeAns: Trunk Line

Most widely used fiber optic cableAns: Single mode step index.

Most widely used RF transformerAns: Toroid

Advantages of toroidal coreAns: Fewer turns, Higher Q, and no shielding

Refers to the general (whole) telephone company that serves communicationsAns: Plant

It is used to increase the power level of AM and other sidebandsAns: Class A or B

It does not affect by the RF carrierAns: Phase modulated emission

Time required for the horizontal scanning lineAns: 63.6 us

It must be on during horizontal flyback time7

Comms Coaching•

Ans: Burst separator

Controls the phase angle of modulated color signal in TVAns: Tint

Non-resonant antennaAns: V-antenna

Information on altitude, etc. of an aircraftAns: Air data

End line of communicationAns: Station wiring

Holds wires, they are conduitsAns: Raceway

It contains PBXAns: Equipment room

Line of sight frequencyAns: VHF and UHF

An antenna used for VHF and higher frequencyAns: Omnidirectional antenna

Frequency conversion and translation Ans: Heterodyning

Cable connected to a cross connect terminal and not directly connected to the local exchangeAns: Home cable

Maximum propagation delay of GEOAns: 278 us

Velocity factor of open-wire lineAns: 0.9

Velecoity factor of coaxial lineAns: 0.8

8

Comms Coaching•

Most widely used modulator Ans: Balanced modulator

Multielement system for controlAns: Key system

Narrowband still pictureAns: Slow scan TV

Average power emitted by laserAns: pulse energy x repetition rate

PCM system used in telephone network and uses TDM techniqueAns: Bell T1

Sampling interval of T1 system Ans: 25 us

Widely used TV modulatorAns: Quadrature detector

Cut-off audio output to prevent annoying noiseAns: Squelch

Permits selective signalingAns: CTCS – continuous tone control squelch

Cut-off frequency of pre-emphasis and de-emphasis networkAns: 2122 Hz

Feedback system used to correct the frequency drift of VHF, UHF and microwave frequency receiversAns: AFC (automatic frequency control)

Produces excellent deviation FM for frequencies below 1 MHzAns: IC VCO

Period of visible HAns: 12.5 us

Period of equalizing pulse9

Comms Coaching•

Ans: 2.29 us

Delay of geosynchronous satelliteAns: 278 us

A VCO in which frequency is varied in proportion to the amplitude of modulating DC or AC signalAns: Subcarrier oscillator

All plants which are “out of doors” not inside the buildingAns: Outside plant

All plants located inside the telephone public exchange buildingAns: Inside plant

Used to terminate telephone wire cableAns: Distrubution frame

It is used to terminate floor distribution cableAns: Floor Distribution Terminal

Portion of a floor service by the floor distribution terminalAns: Floor terminal distribution area

Branch cable of various floor used to connect floor distribution terminal to the riser cableAns: Floor distribution cable

Upstream signal frequency of two wire cableAns: 5- 30 MHz

It is found at the BPA of the TVAns: color level control

2 main barrier of communicationsAns: language and distance

Raceway of rectangular cross sectionAns: header or feeder duct

Terminate cables of telephone servicesAns: Satellite closet

10

Comms Coaching•

Station to private exchange Ans: Local station

Amplitude demodulatorAns: Diode detector

Maximum FM deviation audio modulation for TVAns: 25 kHz

Regulates the use of frequency spectrum and electronic communication in the PhilippinesAns: NTC

Largest category of electronicsAns: Computer

2nd largest category of electronicsAns: Communications

3rd largest category of electronicsAns: Control

Graphical transmission other than TVAns: videotext, teletex, facsimile

Difference of audio and sound for negative transmissionAns: 4.5 MHz

VSWR when terminated at ZoAns: 1

Wires that are in a fire proof ceilingAns: Poke through

Oldest form of modulationAns: AM

Simplest detectorAns: Diode detector

Most common cause of internal noise11

Comms Coaching•

Ans: Thermal agitation

Vary the DC voltage to vary the gainAns: Dual gate MOSFET

vary the collector current to vary the gainAns: BJT

Ceiling and visible area of VFO operating zoneAns: 3048-4827 mi

A feedback that is used to eliminate drift frequencyAns: frequency control oscillator

Rectangular hole on the floorAns: Slot

Increase gain Ans: decrease beamwidth

F connectorAns: RG58U

It is used as mixer (simplest)Ans: Resistor

Insertion loss of fiber opticsAns: 0.38 dB

A tap used in subscriber drop lineAns: high tap loss

Cladding of graded index multimode fiberAns: 0.05 nm

No claddingAns: Laser

Wide beam of missile guidance radarAns: Wide beam

SSB generation12

Comms Coaching•

Ans: filter method

It is used in filter methodAns: Quartz crystal

Suppressed carrier Ans: balanced modulator

Cheap filter methodAns: Ceramic filter

Highest Sound absorptionAns: Celotex

PBXAns: Star topology

Hierarchal topologyAns: SNA

Generator code of CDMAAns: PSN generator

Open ended slot antennaAns: Notch antenna

1544 kbps and 24 VB chAns: u-law

Decay of TV receiverAns: 5 ms

Most positive TVAns: 2nd anode

Common dispersion in fiber opticAns: Absorption and Rayleigh scattering

Popcorn noiseAns: Burst noise

13

Comms Coaching•

Theoretical distance of WiMaxAns: 50 km

Practical distance of WiMaxAns: 3 – 5 mi

Bit rate of BluetoothAns: 2.402 – 2.480 Mbps

CDPDAns: Cellular Digital Packet Data

Data rate of CDPDAns: 19.2 Mbps

Modulation technique of CDPDAns: GMSK

MPEG7Ans: Multimedia Content Description Interface

MPEG3Ans: Motion Pictures Experts Group 1, Audio Layer 3

Ribbon microphone is ___ microphoneAns: Pressure-gradient

Time for V scan lineAns: 1333 us

Under water pressure level sensorAns: Hydrophone

Used for error detectionAns: XMODEM

Discriminator on secondary detectorAns: Doppler radar

Father of internetAns: Vinton Cerf

14

Comms Coaching•

Weak RGBAns: Gray

Strongest signal colorAns: Yellow-green

I signal phaseAns: 57°

GPSAns: 1978

Angle of trust wind parabolic antennaAns: 56°

GPS inclination angleAns: 55°

H scan lineAns: 10.2 us

Fiber optic frequency near ___Ans: 800 THz

Demodulate PCM useAns: low pass filter

Diode detector usesAns: Rectification and filtering

Bandpass filterAns: IF amplifier

Turnstile antenna to feed 2 signals in 1 antennaAns: Circulator

Code 39Ans: Discrete Code

Types of Deiscriminator15

Comms Coaching•

Ans: PLL, Foster Seeley, Quadrature

Not primary superheterodyne receiverAns: RF amplifier

2 oscillatorAns: Black and White

Shadow maskAns: 300,000 holes

CRT capacitanceAns: 2000 pF

Noise margin of Optical fiberAns: 5 to 10 dB

Margin of safetyAns: Power margin

Bluetooth standardAns: IEEE 802.15

IEEE 802.15.4Ans: Zigbee

Data rate of WiMaxAns: 11-54 Mbps

Under the influence of inductance fieldAns: near field

Most dense at nightAns: F layer

Sound corresponds to color of lightAns: Pitch

All waves absorbed and reflectedAns: Labertian reflection

Reflects one color and rejects other16

Comms Coaching•

Ans: dichroic

MatrixAns: Combination circuit TV

FM luminance frequency for VCR recordingAns: 3.5 MHz

Control frequency of VCR1Ans: 30 Hz

Lowest layer for HF propagationAns: C layer

λ/2 150 MHZ at ___Ans: 1 meter

UHF connector to coaxAns: PL259

RS232C hasAns: 25 pins

3G slowAns: 384 kbps

3G fastAns: 144 kbps

3G stationaryAns: 2 Mbps

ILD disadvantageAns: temperature dependent

Reference noise temperatureAns: 290 K

10BASET cable, T meansAns: type of cable used

Convolution 17

Comms Coaching•

Ans: Trellis coding

MPEG 2 usesAns: Cosine transform

Disadvantage of fiber optic cableAns: Cable splicing and simplicity

Flutter echoAns: Successive echo

Telegraph consists of ___ characters plus word spaceAns: 7 ½

Above 10 Hz jitterAns: wander

Telephone wireAns: AWG 19

InterhostAns: Session layer

Measurement of height of ionosphereAns: Ionosonde

PEPAns: 1/3 to ¼

IF Sound carrier cableAns: 45.75 MHz

Connector TV at VCR lowest costAns: F-7 connector

EllipticalAns: Gregorian fed

Resonant antennaAns: Marconi

18

Comms Coaching•

When the main lobe of the array pattern is perpendicular to the array axis, the uniform linear array elements is known asAns: Broadside array

When the main lobe of the array pattern lies along the array axis, the uniform linear array elements is known asAns: end-fire array

What is non-continuous noise of irregular pulses or spikes of short duration with high amplitudes?Ans: Jitter

Strowger switchAns: 1897

Cause of attenuationAns: Walls of waveguide

480 pixel progressive formatAns: 640 x 480

HDTV has ___ more informationAns: 5

Video specification used for video compressionAns: MPEG4

Formula for S/N above 240 channelsAns: S = 4.47 d ( -15 + 10 log N ) N 20 Where: d = 200 kHz

Formula for S/N below 240 channelsAns: S = 4.47 d ( -1 + 4 log N ) N 20 Where: d = 35 kHz

pWpAns: pWp = 0.56 log-1 (90 – S/N)

( 10 )

Flat pWp19

Comms Coaching•

Ans: pWp = log-1 (90 – S/N) ( 10 )

Kr TE10

Ans: kr = 3.83

Kr TE11

Ans: kr = 1.84

Klystron factorAns: k = ____fo______

2(n+1)(1+2Vo)

ModeAns: mode = n +(3/4)

FormulaAns: 10 log (ng+ni)2

(ng-ni)

Relative permittivity of PVCAns: 3.3

Relative permittivity of polyethyleneAns: 2.27

NTSC Ans: 0.7 NL

PALAns: 0.8NL

Effective noise bandwidthAns: BWeff = (π/2)(BW3dB)

Parabolic antenna gain with respect to beamwidth Ans: G (dB) = 10 log (203/φ)2

BeamwidthAns: φ = 203

(√10)G(dB)/10

20

Comms Coaching•

Five wire lineAns: Zo = 173 log __D__

√ξr 0.933 d

Balanced line between grounded parallel planes Ans: Zo = 173 log _4h tanh (πD/2h)_

√ξr πd

Number of modes fiber opticAns: M = 0.5 (πD NA/λ)2

Q of SSBAns: Q = fo (log -1 dB/20) 1/2

4Δfi

Reliability based on propagationAns: Undp = abfGHz

1.5 dmi3 (1.25 x 10-6)10-FM/10

R = (1- Undp) x 100%

Reliability based on equipment failuresAns: U = Outage time in hours/year

8760 hours

Earth’s curvatureAns: EC = d1d2

1.5k

Absorption coefficientAns: α = δa/S

δa = (55.3 V/v)(1/t1 – 1/t2)

Effective noise BW parallel tuned circuitAns: BWeff = 1/(4RpC)

Reject a single color and allow other colorsAns: Dichroic

Hertz antenna used above Ans: 2MHz

21

Comms Coaching•

Elliptical reflectorAns: Gregorian Fed

Used in LOS transmissionAns: VHF

Used in submarine applicationsAns: ELF

Used in marine and aeronautical communicationsAns: L-band

Lowest attenuation fiber optic lengthAns: 1000 ft

Longest wavelengthAns: Orange

Results from the combination of weak blue, red and greenAns: Gray

Electron gun goes straight to the picture tubeAns: Green

Protocol which uses checksum as error detection schemeAns: XMODEM

Video specification used for video compressionAns: MPEG4

Used in European Cordless TelephoneAns: GFSK

Microwave telephone via satelliteAns: Arthur Clarke

Foundation of acoustic theory in buildingsAns: Wallace Sabine

22

Comms Coaching•

Father of InternetAns: Vinton Cerf

Chrome type cassette tapeAns: Type 2

Protection from snow and windAns: Radome

Daytime ; reflect low frequencies, absorb medium frequenciesAns: Layer

Most denseAns: F2 layer

transequatorial propagation Ans: best in afternoon and early evening

Aspect ratio of HDTVAns: 16:9

Without bottle necksAns: Mesh

480 pixel format Ans: 640 x 480 pixel progressive

Lifetime of LEDAns: 200,000 hrs

Number of holes in shadow maskAns: 300,000

Lead oxide camera tube Ans: Plumbicon

Acts as an antenna at high frequenciesAns: Transmission line

Reference in dbaAns: -85 dBm

23

Comms Coaching•

Reference temp in noise analysisAns: 290 K

Audible frequency rangeAns: 16 Hz – 16 kHz

RG62 to avoid reflection use Ans: 93 Ω

Used in thick EthernetAns: RG11

RS232C Ans: has 25 pins / 20 kbps

1 supergroupAns: 75 groups

Heating voltage of TV picture tubeAns: 6.3 V

Wi-FiAns: 11-54 Mbps

WiMax theoretical rangeAns: 50 km

WiMax practical rangeAns: 3 to 5 miles

1 jumbogroupAns: 3600 VC

BluetoothAns: IEEE 802.15

WiMaxAns: IEEE 802.16

Zigbee24

Comms Coaching•

Ans: IEEE 802.15.4

Angular separation between half-power pointsAns: Beamwidth

Prevent FM from enteringAns: Diplexer

Not temperature dependentAns: ILD

Color subcarrierAns: 3.58 MHz

Highest absorbent coefficient materialAns: Celotex

Glass Ans: highest optical characteristics ; lowest attenuation

PCS fiber optic Ans: glass core

Glass Ans: lower velocity than air

Glass Ans: has lower index of refraction than water

Sound is absorb on wallsAns: Anechoic

Cause of attenuationAns: Walls of waveguide

Bending of light from high density to low densityAns: Refraction

Adjustment used by means of loudspeaker feedback systemAns: Ambiophony

25

Comms Coaching•

Uses convolutional coding Ans: Trellis Coding

Inverter CMOS Ans: has two transistors

SSB Ans: AM

Uses CSMA/CD ; 10 MbpsAns: Ethernet

Structure which supports cablesAns: Cable Tray

GPRS uplink rateAns: 14 kbps

Tunes to a radio frequencyAns: Local oscillator

Two PBXAns: Tie Trunk

Hierarchical topologyAns: SNA

Types of demodulator : Ans: PLL, Quadrature and Foster – Selley

Violet ray Ans: 4000 Angstrom = 0.4 micron

PopcornAns: Burst noise

Used to view the envelop of a modulated signalAns: Oscilloscope

Power output of sideband envelopeAns: Peak Envelop power

26

Comms Coaching•

Disadvantage in using FOCAns: Splicing

Causes distortion on the demodulated signal (delta modulation)Ans: Slope overload

Spread spectrumAns: DSSS

Mostly used in satellite communicationsAns: TDMA

High internal resistanceAns: Nickel Iron

Protection against snow and wind loadingAns: Radome

Fiber optic performance Ans: bit rate

Attenuation expressed in Ans: dB/um

UHF connector Ans: PL259

CDMA Ans: no limitation in BW

Interface reduction Ans: co-channel

2 diff amplitudes, 2-phaseAns: QAM

Fgure of merit with FSKAns: h factor

OSI layer – buildings

27

Comms Coaching•

Ans: Novell Network

FluctuationsAns: Fading

Most common light generatorAns: ILD

Lifetime of LCDAns: 200,000 years

BFO of SSBAns: Carrier oscillator

Freq hopping, assign diff carrier freqAns: CDMA

Antenna complete in itself and self-oscillatingAns: Hertz Antenna

Unique binary code for CDMA satelliteAns: Chip code

Output of magnetic microphoneAns: 1 mV

350-440 HzAns: call-waiting tone

Connect telephoneAns: Induction coil

Conduit, reduce abreactionAns: Bashing

Most reliable for error detectionAns: CRC

Use 2 mixers, filter & phase-shiftAns: Balanced modulator

28

Comms Coaching•

1% left in the TVAns: Screen persistence

Unconscious level heard by human earAns: 6-10 dB

Microwave range of freqAns: Window

Marginal safety for microwaveAns: 5 – 10 dB

Luminance FM for VCRAns: 2.5 MHz

Non-directional horizontally polarizedAns: VHF & UHF

Stereo pilot carrier Ans: 19 kHz

Dipole resistanceAns: 73 ohms

RG-65 Ans: 93 Ω

Complex pressure amplitude over complex amplitude volumeAns: Acoustic impedance

Optical densityAns: Radiant flux

HDTV Ans: 16:9

Calls not satisfiedAns: Erlang C

PBXAns: Star topology

29

Comms Coaching•

Blanking pulse of negativeAns: 75%

Beginning & end of the char codeAns: Character Synchronization

Improve AM broadcast timerAns: Counterpoise

Visible signalAns: Infrared

Variations in signal strength by atmospheric conditionsAns: Fading

For abrasionAns: Abrasion

Known for power amplificationAns: Class A

Injection laser diode Ans: APD

1st radio receiverAns: Crystal

Communication for vehicle, groundAns: Marconi

Visible wavelengthAns: 0.4 to 0.8 micron

Radiation directionAns: End fire array

IMPATTAns: 30 GHz

Logic network in form of an array30

Comms Coaching•

Ans: Matrix

Across resistorAns: Shot noise

Information capacity Ans: Shannon Hartley theorem

Divide digital dataAns: Converter

Sum of minterm & product of maxtermAns: Canonical

Handset local loopAns: Induction coil

Figure of merit in lightAns: Numerical aperture

All constantAns: Diatonic

Purity of colorAns: Q & I amplitude

Maximum brightnessAns: 50% Red 59% Green and 11% Blue

Handshaking principleAns: Delta modulation

Handshaking principleAns: Synchronous

Error correction at high frequencyAns: ARQ

UnicodeAns: 16 bit long

High frequency AM31

Comms Coaching•

Ans: PIN diode

ModemAns: PSK

Absorption of impedance TubeAns: α = 4A1A2

(A1+A2)2

Impedance acousticsAns: Newton seconds per cubic meter

WiMax data rateAns: 500 kbps – 8 Mbps

FormulaAns: ft = fo + kfoΔT

Blind velocityAns: Vb = PRF(nλ/2)

Spacing of transmission lineAns: S = λL/360

Transfer of one adjacent walls to anotherAns: Flanking transmission

Range that accepts signal interferenceAns: Blocking range

Sound deduction indexAns: Transmission loss

Internet cable 6 MHzAns: 27 Mbps

Not terrestrial TVAns: 8-V.58

Lowest attenuation UHFAns: N-type

32

Comms Coaching•

HFAns: affected by the solar cycle

Pag tinanong linear bit PCM codeAns: n-1

PhotonAns: E = hf/c h=6.634 x 10-34

SSBAns: HF

High ZAns: Crystal

U600 bandwidthAns: 2520 MHz

Standard VBAns: 300 – 3400 Hz

Voice gradeAns: 0 – 4 kHz

170 Ω/km Customer loopAns: AWG22

Determine attenuation to troposcatterAns: Scatter angle

CompressionAns: SSB = 20 log cot(φ/2)

KlystronAns: n +3/4

TimeAns: TD = 1.016 √ξr (length) ns/ft

0 = 360 TD

T33

Comms Coaching•

One tenth of the wavelengthAns: Elementary doublet

FOC data rate Ans: data rate = 1/5Dd

Minimum heightAns: λ/4

Theoretical heightAns: λ/2 vertical antenna

LORAN C/D accuracyAns: 460 m

COR/DME ground navigationAns: 108 – 118 MHz

Repeater fiber optic cableAns: 10 – 30 km

dBaAns: 1 uV/m

Bridge Ans: Physical and data link

Transmission and reception of informationAns: Session

Transmission of bitsAns: Physical

Start bitAns: 0

Stop bitAns: 1

Noise temperature34

Comms Coaching•

Ans: 17°C

AC cableAns: All of the above

Not specification of 3GAns: IMT2000

BW efficiencyAns: Information density

ResolutionAns: Resolution = Vmax/DR

Quantization errorAns: Q = (1/2)Res

Isolation CATVAns: 28 dB

Output terminal match CATVAns: 16 dB

Disadvantage of plastic over glassAns: High attenuation

Mnimum illumination for readingAns: 8000 Ix

Impedance at open end of half wave antennaAns: 2500 ohms

Max data rate of fiber optic systemAns: 10 Gbps

Data rate of TDMAAns: 8 kbps

WiMaxAns: 500 kbps to 8 Mbps

35

Comms Coaching•

H21 broadband ISDNAns: 32.786 Mbps

Data rate of terrestrial digital TVAns: 32.28 Mbps

V.34Ans: 33.6 kbps

GPRSAns: 172.2 kbps

BluetoothAns: 72 kbps

V.22Ans: 1200 kbps

V.90Ans: 56 kbps

V.32Ans: 9.6 kbps

Speed of IS-95 CDMAAns: 1.23 Mbps

WiFi / wireless internet service providerAns: 11 Mbps

WiFi specAns: IEEE 802.11b

Spacing between M88 loading coilsAns: 9000 ft

Area above the vertical antennaAns: curve of silence

under the influence of the induction fieldAns: near field

36

Comms Coaching•

FM luminance frequency for VCR recordingAns: 3.5 MHz

Measure of comparison of sound intensity with another Ans: decibel

Used in optical system and satellite telemetry linksAns: biphase codes

Divide into 4 by ITUAns: Facsimile groups

Code transparency with frequencyAns: bit oriented protocol

ERP of class 2 cellular mobileAns: 1.6 W

Max power for class I analog mobileAns: 600 mV

Appears at nightAns: F2 layer

High frequency daytime propagationAns: E layer

MF range wavelengthAns: Hectometric waves

Protocol for packet switching networksAns: X.75

Electronic serial numberAns: 32 bits

Most luminanceAns: Yellow

Used by Marconi antenna37

Comms Coaching•

Ans: below 2 MHz

Mogul-Dellinger fadeout Ans: sudden ionospheric disturbance frequency

Most commonly used characters are represented in fewer bitsAns: Huffman encoding

On time of FETsAns: Acquisition time

Term for byte in ATMAns: Octet

Used in 10/100 Mbps EthernetAns: ISTP cable

Not used in TVAns: 108 MHz – 114 MHz

Does not use error checkingAns: Physical layer

Demodulates audio signal in TVAns: Discriminator

Together with mixerAns: local oscillator

Not used in mobile tel.Ans: balanced detector

Guardband of C-band satellite comm.Ans: 4 MHz

Minimum quality circuit available in PTNAns: basic voice grade

Multichannel network Ans: broadband

38

Comms Coaching•

Standard test toneAns: 1000 Hz

Average human absorptionAns: 4.7 units or sabines

Max. critical angleAns: Acceptance angle

Software used in preparing packetsAns: internet protocol

No modulationAns: Rest frequency

CMTS(AMPS)Ans: Less than 2%

Speed of longitudinal waves Ans: is proportional to the compressibility of the medium

EIRP Class II Cellular Ans: 1.6 watts

Pulse dialingAns: 10 pulses/sec or 600 pulses/minutes

Single-sideband full-carrierAns: H3E

Retain local number to access (migration)Ans: Local number portability

‘raceway’Ans: Header

Fastest multimedia peripheralsAns: Firewire

Output Class I mobile output minimumAns: 600 mV

39

Comms Coaching•

Smallest unit data for networkAns: Packet

UTC Ans: UTA

Mod used for IS-95Ans: QPSK (DSSS)

Propagation delay for TDM periodAns: 577 us

Difference freq for forward and backward transmissionAns: 45 MHz

Gain at the direction of the major lobeAns: Directivity Gain

Code transparencyAns: Bit-oriented protocol

AM broadcast antenna heightAns: λ/2 vertical antenna

Synchronization 1 VAns: Scanning line

Can be eliminated using helical antennaAns: Faraday rotation

Companding Ans: protect small signals from quantizing distortion

Current Maximum for ¼ wavelength Marconi AntennaAns: at the base

Synchronous data transferAns: CMT

Electrical signals converted for microphoneAns: 25 – 8000 Hz

40

Comms Coaching•

Reference sound levelAns: 0 dBm

Bessel 1.0 modulation indexAns: 3 pairs of sidebands

Common coaxial characteristic impedanceAns: 50Ω and 75Ω

Dead space Ans: due to shading of hills and trees

Formulas: θ=

360 ° T DT

(phase shift)

T=1f

TD=1.016√∈d ns/ft (d in ft)

Illuminated reflector

θ=142 °√G

(beamwidth), (G = in gain ratio)

f=f o+k f o∆T

8 kHz1MHz

→Hartley

1ppm → 1Hz1MHz →crystal

BER = (bit error rate)

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Comms Coaching•

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