# Communications Engineering Coaching Materials: Section 3 Module 4

This is the Section 3 Module 4 of the compiled Communications Coaching Materials taken from different sources including but not limited to Communications books, past Board Exams Questions, Journals and the Internet.

This is the Section 3 Module 4 of the compiled Communications Coaching Materials taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies (EST), Communications Books, Journals and other Communications References. This particular Coaching Notes in Communications Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.

### Communications Engineering Coaching: Section 3 Module 4

· Modem

Ans: PSK

· Absorption of impedance Tube

Ans: Î± = 4A1A2 / (A1+A2)2

· Impedance acoustics

Ans: Newton seconds per cubic meter

· WiMax data rate

Ans: 500 kbps – 8 Mbps

· Formula

Ans: ft = fo + kfoÎ”T

· Blind velocity

Ans: Vb = PRF(nÎ»/2)

· Spacing of transmission line

Ans: S = Î»L/360

· Transfer of one adjacent walls to another

Ans: Flanking transmission

· Range that accepts signal interference

Ans: Blocking range

· Sound deduction index

Ans: Transmission loss

· Internet cable 6 MHz

Ans: 27 Mbps

· Not terrestrial TV

Ans: 8-V.58

· Lowest attenuation UHF

Ans: N-type

· HF

Ans: affected by the solar cycle

· Pag tinanong linear bit PCM code

Ans: n-1

· Photon

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

· SSB

Ans: HF

· High Z

Ans: Crystal

· U600 bandwidth

Ans: 2520 MHz

· Standard VB

Ans: 300 – 3400 Hz

Ans: 0 – 4 kHz

Ans: AWG22

· Determine attenuation to troposcatter

Ans: Scatter angle

· Compression

Ans: SSB = 20 log cot(Ï†/2)

· Klystron

Ans: n +3/4

· Time

Ans: TD = 1.016 √Î¾r (length) ns/ft

0 = 360 TD / T

· One tenth of the wavelength

Ans: Elementary doublet

· FOC data rate

Ans: data rate = 1/5Dd

· Minimum height

Ans: Î»/4

· Theoretical height

Ans: Î»/2 vertical antenna

· LORAN C/D accuracy

Ans: 460 m

Ans: 108 – 118 MHz

· Repeater fiber optic cable

Ans: 10 – 30 km

· dBa

Ans: 1 uV/m

· Bridge

· Transmission and reception of information

Ans: Session

· Transmission of bits

Ans: Physical

· Start bit

Ans: 0

· Stop bit

Ans: 1

· Noise temperature

Ans: 17°C

· AC cable

Ans: All of the above

· Not specification of 3G

Ans: IMT2000

· BW efficiency

Ans: Information density

· Resolution

Ans: Resolution = Vmax / DR

· Quantization error

Ans: Q = (1/2)Res

· Isolation CATV

Ans: 28 dB

· Output terminal match CATV

Ans: 16 dB

· Disadvantage of plastic over glass

Ans: High attenuation

Ans: 8000 Ix

· Impedance at open end of half wave antenna

Ans: 2500 ohms

· Max data rate of fiber optic system

Ans: 10 Gbps

· Data rate of TDMA

Ans: 8 kbps

· WiMax

Ans: 500 kbps to 8 Mbps

Ans: 32.786 Mbps

· Data rate of terrestrial digital TV

Ans: 32.28 Mbps

· V.34

Ans: 33.6 kbps

· GPRS

Ans: 172.2 kbps

· Bluetooth

Ans: 72 kbps

· V.22

Ans: 1200 kbps

· V.90

Ans: 56 kbps

· V.32

Ans: 9.6 kbps

· Speed of IS-95 CDMA

Ans: 1.23 Mbps

· WiFi / wireless internet service provider

Ans: 11 Mbps

· WiFi spec

Ans: IEEE 802.11b

Ans: 9000 ft

· Area above the vertical antenna

Ans: curve of silence

· under the influence of the induction field

Ans: near field

· FM luminance frequency for VCR recording

Ans: 3.5 MHz

· Measure of comparison of sound intensity with another

Ans: decibel

· Used in optical system and satellite telemetry links

Ans: biphase codes

· Divide into 4 by ITU

Ans: Facsimile groups

· Code transparency with frequency

Ans: bit oriented protocol

· ERP of class 2 cellular mobile

Ans: 1.6 W

· Max power for class I analog mobile

Ans: 600 mV

· Appears at night

Ans: F2 layer

· High frequency daytime propagation

Ans: E layer

· MF range wavelength

Ans: Hectometric waves

· Protocol for packet switching networks

Ans: X.75

· Electronic serial number

Ans: 32 bits

· Most luminance

Ans: Yellow

· Used by Marconi antenna

Ans: below 2 MHz

Ans: sudden ionospheric disturbance frequency

· Most commonly used characters are represented in fewer bits

Ans: Huffman encoding

· On time of FETs

Ans: Acquisition time

· Term for byte in ATM

Ans: Octet

· Used in 10/100 Mbps Ethernet

Ans: ISTP cable

· Not used in TV

Ans: 108 MHz – 114 MHz

· Does not use error checking

Ans: Physical layer

· Demodulates audio signal in TV

Ans: Discriminator

· Together with mixer

Ans: local oscillator

· Not used in mobile tel.

Ans: balanced detector

· Guardband of C-band satellite comm.

Ans: 4 MHz

· Minimum quality circuit available in PTN

· Multichannel network

· Standard test tone

Ans: 1000 Hz

· Average human absorption

Ans: 4.7 units or sabines

· Max. critical angle

Ans: Acceptance angle

· Software used in preparing packets

Ans: internet protocol

· No modulation

Ans: 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 dialing

Ans: 10 pulses/sec or 600 pulses/minutes

· Single-sideband full-carrier

Ans: H3E

· Retain local number to access (migration)

Ans: Local number portability

· ‘raceway’

· Fastest multimedia peripherals

Ans: Firewire

· Output Class I mobile output minimum

Ans: 600 mV

· Smallest unit data for network

Ans: Packet

· UTC

Ans: UTA

· Mod used for IS-95

Ans: QPSK (DSSS)

· Propagation delay for TDM period

Ans: 577 us

· Difference freq for forward and backward transmission

Ans: 45 MHz

· Gain at the direction of the major lobe

Ans: Directivity Gain

· Code transparency

Ans: Bit-oriented protocol

Ans: Î»/2 vertical antenna

· Synchronization 1 V

Ans: Scanning line

· Can be eliminated using helical antenna

· Companding

Ans: protect small signals from quantizing distortion

· Current Maximum for ¼ wavelength Marconi Antenna

Ans: at the base

· Synchronous data transfer

Ans: CMT

· Electrical signals converted for microphone

Ans: 25 – 8000 Hz

· Reference sound level

Ans: 0 dBm

· Bessel 1.0 modulation index

Ans: 3 pairs of sidebands

· Common coaxial characteristic impedance

Ans: 50â„¦ and 75â„¦

Ans: due to shading of hills and trees

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