Communications Engineering Coaching Materials: Section 5 Module 11

This is the Section 5 Module 11 of the compiled Communications Coaching Materials taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies (EST), Communications Books, Journals and other Communications References. This particular Coaching Notes in Communications Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.

Communications Engineering Coaching: Section 5 Module 11

#	Questions	Answers
1	Number of turns of a helix antenna	3
2	Highest layer of the ionosphere during night time	F layer
3	Oxygen causes what attenuation at what frequency	60 GHz
4	One sideband	H3E
5	Thickest layer of the ionosphere	F2
6	F1 and F2 layer combines at night time at what distance	300km
7	Class of Amplifier used at the last stage of AM receiver	class C
8	Front-end “components” of the superheterodyne receiver	local oscillator, mixer, RF amplifier
9	Fiber optic used for electronic communication	semi-graded Fiber Optic
10	Carrier swing at 80% modulation	120 kHz
11	H designates what kind of modulation	single sideband / DSB
12	Used for testing to avoid interference	dummy antenna
13	How to prevent interference with the frequency of other stations during testing	use a dummy antenna
14	data switching is used to	increase rate of data transfer
15	Periscope antenna	shorten waveguide link
16	one hop, full-duplex uses how many receivers	2
17	full duplex multiplexer	two way simultaneous transmission
18	a room with great sound absorption and less reverberation time	dead room
19	measures speech volume	volume unit meter
20	luminance	30% red, 59% green, 11% blue
21	unit of noise power in posphometer	pWp
22	group 1 frequency assignment for color black	2300-2400 Hz
23	group 1 frequency assignment for white	1500 Hz
24	quarter wavelength crystalline calcite device that reverses polarity of the fiber optic communication	retarder
25	Distortion caused by simultaneous frequency and amplitude modulation and carrier frequency	dynamic instability
26	Size of a mini dvd	8cm
27	Size of a standard dvd	12cm
28	Antenna height is _____ of the actual height	½ to 2/3
29	Reference noise power of test tone	1mW
30	Unit of white noise voltage testing measurement	NPR
31	SSB uses ___ of the bandwidth of the DSBSC	½
32	Indicated the maximum channel capacity	Shannon-hartley theory
33	not an advantage of series modulation	suppresses white noise
34	asynchronous protocol is ___ oriented	character
35	V-designation for 4.8 kbps modes	V.27
36	For video 3.4 Mbps	J.81
37	Rid of FM noise	Limiter
38	Advantage of side tone	assure that the telephone is working
39	At what power level does a 1kHz tone cause zero interference (144 weighted)	90 dB
40	Reference frequency of CCITT phosphometer noise measurement	800 Hz
41	device that modulates an analog carrier signal to encode digital information in a telephone line	MODEM
42	Number of ships area assigned by the global maritime distress	4
43	Not required on board by the maritime distress	radio operator telegraphy on board
44	Efficiency of Class 4 MODEM	120%
45	frequency at which fiber optics operates	800THz
46	industrial noise frequency	15-160 MHz
47	what is optic window?	range of wavelength at which Fiber Optics operates
48	transmission lines are balance or unbalanced with respect to	ground
49	at 41.000 MHz to 41. 005 MHz and a channel capacity of 12.5kHz, what is the first center frequency	41.00625 MHz
50	wind loading of standard for Philippine antenna tower	200kph
51	energy that neither radiated into space nor completely transmitted	standing waves
52	Identifies the address of the webpage	uniform resource locator
53	electromagnetic radiation	James Clerk Maxwell
54	highest frequency wherein the signal is able to return back to earth	MUF
55	ISDN basic access line configuration	2B + D
56	FM and PM difference	lies in the different definitions of modulation index
57	1 erlang	1 TU
58	The minimum value of the occupied bandwidth sufficient to ensure the transmission of information at the rate and with the quality required for the system employed, under specified conditions	Necessary bandwidth
59	Electric field is perpendicular	TE
60	Electromagnetic wave having circular polarization means	electric field rotates
61	Reverberation time for large organs is ____ seconds	2
62	Camera output with no sync	noncomposite video
63	Bandwidth of AM	based on the highest component of the modulating signal
64	Advantage of PTM over PAM	much better noise immunity
65	In phase shift method, how many circuits is/are balanced	2
66	Frequency range of an aircraft’s VHF communications	118.000 MHz to 136.975 MHz (worldwide up to 151.975 MHz)
67	Detect signals that is both vertically and horizontally polarized simultaneously	Orthomode transducer
68	the reason why companding is employed in PCM is	protect small signals in PCM from quantizing distortion
69	the process that uses the orthogonality of sines and cosines that makes possible to transmit and receive to different signals simultaneously on the same carrier frequency	Quadrature multiplexing
70	unit of magnetic field strength	ampere/meter
71	the standard that specifies a balanced interference cable that will operate bit rates up to 10Mbps with a span distance of up to 1200m	RS-422A
72	when light strikes a flat polished end of a fiber, the fiber loss produced can be reduced by	antireflection coating
73	Total elapsed time for the instant of initial transmission to the reception of the echo in radar communication system	12.36microseconds
74	Used to collect RF signal in the receiver	antenna
75	Paging channel of a mobile communication network system	9.6, 4.8 kbps
76	Difference between synchronous and asynchronous transmission	the clocking is with the data of the synchronous transmission
77	local loop	two-wire or four-wire communication system that connects residences to central office premises
78	not describe a TV signal	“spreading” of color is not always white (note: spreading is not the real term in the answer. sorry)
79	transfer rate when 101001 data is transferred at 6ms	1kbps
80	binary communication is better because	simpler, less costly, reliable
81	consideration of new entrant	technical, financial, legal
82	gain of 4 identically polarized antenna stacked one above the other	6dB over the gain of one antenna
83	when played in piano or other instruments, note similar to the pitch of 440 Hz is	note A above middle C
84	slow drift in frequency for self-excited transmitter oscillator circuit resulting to poor frequency stability	DC and RF heating of resistors then changes its values
85	slow drift in frequency for self-excited transmitter oscillator circuit resulting to poor frequency stability	Heating of capacitor in the oscillator
86	abrupt frequency variation of self-excited transmitter oscillator circuit resulting to poor frequency stability which changes frequency oscillation	loose connection of oscillator, amplifier and antenna
87	Electromagnetic wave below 5000 GHz being transmitted without artificial guide	hertzian wave
88	Propagation condition usually indicated when VHF signal is received from a station over 500 miles away	tropospheric ducting
89	Used to connect data link	bridging function
90	a fiber optic communication device consist of receiver transmitter used to clean up and amplify digital data moving from one place to another at opposite direction	optic regenerator
91	in sound energy, dominance of the first sound wave in any point of location has ____ effect	precedence
92	ratio of the level of modulated signal under the conditions of test modulated signal to the level of unmodulated signal without modulation	residual noise level
93	an entity, relying transmission, switching and local distribution facilities of local exchange and inter exchange carrier and overseas carriers providing enhanced services beyond provided by such carriers	value-added service provider
94	not a common application of microwave communication	mobile radio
95	___ is a character signifies the start of the test for Bisync	STX
96	Oscillator “leak through” of neutralized amplifier	back wave
97	In Ethernet, an 8-bit frame similar to that of a preamble which last two bits are 1s	start of frame delimiter
98	In data communications, the maximum variable-length transmission packet is 4096 bytes and the default is _____ bytes	128
99	Type of emission used for radio telegraph and sidebands on the carrier	Spark emission
100	Average power of a radio transmitter supplied at the transmission antenna	mean power
101		ionospheric scatter

Complete List of Communications Engineering Coaching Materials

Communications Engineering Coaching Materials

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