Communications Engineering Coaching Materials: Section 1 Module 4

This is the Section 1 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 1 Module 4

QUESTIONS	ANSWERS
What is the maximum VF tone that may be fed to a voice signal	+6 dB
What is the maximum power of the Class 1 analog mobile phone	600 mW
The average voltage value of the 3.58MHz modulated chrominance signal in TV receivers is___________	The brightness of the color
How many lines does a standard NTSC has?	525
F3 emission means carrier frequency is modulated by _______	Voice
The aeronautical radio navigation land station that provides direct bearing on that station from an aircraft is known as _____________	Omni-directional range station
What is the frequency tolerance for aircraft station employing SSB transmission?	20 ppm
The range of the human hearing can form how many octaves	10
What results in the luminance components interfering in the color signal, it occurs whenever there is diagonal detail on that picture and gets worse with motion	Cross luminance
How many horizontal lines are blanked out in the frame of TV receivers by V blanking	42
What would be the bandwidth of an AF filter for CW	500 to 1000 Hz
A superjumbo group has how many voice band channel	10800
A characteristic of the modulating signal that is proportional with the amount of frequency deviation from the carrier center frequency in FM	Amplitude
“?” requires that the amplitude of each sample be converted into ______	Binary number
In the single tube class C amplifier why is the “?” modulated envelop that made up of varying amplitude dc pulses	Because of flywheel
What is the data transmission rate of the North American AMPS	10 kbps
The split pair is used by IBM token ring network that operates at either	4 or 16 Mbps
In acoustics, what do you call the present combination of interval	Consonant interval
What is a system where cables and wires are placed within the ceiling and poked up in the resistance floor structured to office or the room above	Poke probe
3G wireless system was introduced in what year	2001
In telephone system, what traffic model is based on the assumption that calls are not immediately satisfied that the first attempt are held in the system until it is satisfied	Poisson
What is the maximum VF tone that may be fed in the telephone line	0 VU
What type of modulation is produced by sampling an analog signal	PAM
What is the number of lines scan per frame in the raster on the picture tube	525
What is the velocity of the geostationary satellite in orbit	6879 statute mph
Which navigation does not have global range	MLS
What refers to the system where an aircraft’s navigation aid measures the time interval between an interrogatory pulse and the reply from the radar from a radar beacon	DME (Distance Measuring Equipment)
What is the accuracy of LORAN C long range hyperbolic radio navigation system	¼ of a mile absolute & >100ft
What is the main advantage of GPRS	It doesn’t require a connection
How many TV fields are recorded on one slant track of tape	1
What frequency sharing technique uses highly directional spot beam antennas to prevent interference between stations of the same frequency.	Spatial isolation
What is used to produce low power microwave oscillators	Tunnel diode
What is the variation of the discriminator which greatly reduces sensitivity to amplitude variations and causes a 50% reduction in output voltage	Radio detector
Under the revised regulation governing cable TV systems in the Philippines regular duplicated by the network programming by one or more station in a week during the hours of 6 to 11 PM local time to a total of how many hours or more?	14 hours
What is the minimum rejection of a CATV system	60 dB
In CATV system what is sound section isolation	40 dB
In CATV system what is the RF output terminal match	16 dB
In the NTSC regulation, how much is the fine for the MPSC operating without valid NTC permit	Php5000
What is the term for the ratio for the luminous power to the radiant power in the sample of light and expressed in lumens per watt of gradient energy	Luminosity
What do you call a special microwave coaxial cable which is made of hard tubing rather that wire with an insulating cover that can be used on the lower microwave band	Hard line
Which of the following are antennas made with micro strip on PCBs	Patch antenna
Which coaxial connector is of more complex and expensive that do a better job in maintaining the electrical char of the cable through interconnection	n-type connector
What is the dielectric constant of polyethylene insulator	2.27
How is tapped single button microphone cleared?	Jarred
What helps protect fiber against degradation cause by moisture	Cabling
For an angle of incidence = to the critical angle the light will be refracted	Along the normal
How much more feed point Z does a folded dipole have than normal dipole	4 times
What filter may be connected between a CB transmitter and its antenna	Low pass filter
When real time communication is required the only way to address the second fragment is to use a ____ containing more that 1 satellite	Constellation
What is the common usage of single button microphones	In telephones
What is the advantage of using hub over direct interconnection to all the terminals	Its easy to move computers
A broadcast station is transmitting but not modulating, what is heard in a receiver tuned to its frequency	Nothing
A network using microwave for two way transmission of telephony and in high speed data	Local Multipoint Distribution System (LMDS)
In TV system, if the 3.58MHz C amp in the receiver does not operate, the result will be __________?	No color
What refers to the emphasizing low level signals and compressing high level signals	Companding
A system that allows user to access documents from widely separated sources of the internet using a common interface	WWW
What is the max efficiency of class C amp?	100%
What is the max recommended cable length of RS232C cable?	50 feet
What is the typical value of line turn around?	1.5 ms
Which pulse in the V blanking corresponds to 3H lines wide?	V sync
What refers to the nonlinear effect that occurs at low power as low as 3mw in single mode fiber and takes the form of a light shifter slightly in frequency from the original light wave	Bruilloin scattering
In wide area networks what routing technique requires each node to take the incoming packet and retransmit it onto every outgoing line?	Flooding
For analog dram scanners what type of modulation is used after the receive light has been converted into electrical energy?	FM
What is the most commonly used transmission line?	Coax cable or line
In what 2 systems in the voice transmitter can speech processing be used?	AF and RF
What can be determined about a transformer by an ohmmeter?	Winding continuity, shorts to case and interwinding shorts
Why is a matched line indistinguishable from an infinitely long line as seen from the source?	Since no energy is reflected from the match load, so for the source it appears as if energy is put into the line continuous to move down the line forever
What type of circuit produces even order harmonics?	Push-pull
What is the designation of SSB with full carrier?	H3E
What is the achievable data rate of the 3G cellular system?	More than 2Mbps
What is the time period for a single time slot in GSM TDMA structure?	8
What packets switch data technique is used with the GSM systems?	GPRS
What do you call the process by analog signal are transmitted by converting them into a series of pulses whose amplitude is approximately the shape of the analog signal	PAM
In Ethernet LAN, what situation arises when two or more terminals try to transmit in the network at the same time?	Contention
What do you call the interval which it’s an integer or whole fraction ratio	Octave interval
What is defined as the ratio of frequency of two pure tones?	Interval
What do you call the first note of the musical scale?	Root note
In what year will the FCC face the analog broadcasting?	2006
Which of the following is or are parts of the network interface card?	Both BNC and RJ49 connectors
Which of the ff wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonance in the water vapor molecule	1.35cm and 1.7mm
What class of mobile phone has a maximum power level specified as ERP of -2dBW or 600mW	Class III (mobile phone)
What refers to a series of tones that sounds good when used in combination	Musical scale
An MPD shop properly identifies its business and location by posting conspicuously at the entrance of its premises a sign board, what are the dimensions of the sign board?	50cm x 100cm
Electronic technician as defined by the MPSCP implementing guidelines should be a graduate of an electronic technician course and should have completed a formal training course in the repairs, servicing and maintenance of mobile phones conducted by mobile phone manufacturers and or training service center duly accredited by _________	TESDA
Under RA 9292, one qualification to be a member of the board is being a citizen and resident in the Philippines for at least how many years?	5 years
What technique is employed by the transmitter to avoid accidental flags	Bit stuffing
If two signal are in quadrature, what tie the phase relation	90 degrees
What do you call a type of communications by propagation is primarily by the direct or space wave which travels in straight line at frequency above 30Mhz	LOS communication
What feature of SONET allows data spin with different paths to be sync	Payload pointer
What is a specialized transformer that allows telephone voice signals to travel in both directions simultaneously in a single twisted pair loop	Hybrid coil
Cable TV companies collect signals and programs from many sources in a facility called ____________	Head end
Refers to the transmission of multiple TV signals which are frequency multiplexed on a single cable to be used in lieu of over the air signal trans	Cable TV
What is the other name of super refraction	Ducting
What is the reason why tropospheric ducting not used very much in practical communication systems?	Because it is not reliable
What is the function of a hybrid in the telephone handset	Decrease mic signal in phones
When the called telephone is ringing, the CO sends a pulse AC voltage to the calling telephone. What is that signal called?	Ringback signal
What unit refers to radiation other than x-rays which will have an absorption equal to 1 roentgens	Rep - roentgen equivalent physical
Different sources of radiation have different effect which are related to x-rays by a number which is referred to as the ______	Rbe – roentgen biological effectiveness

Complete List of Communications Engineering Coaching Materials

Communications Engineering Coaching Materials

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