Communications Engineering Coaching Materials: Section 5 Module 4

This is the Section 5 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 5 Module 4

#	Questions	Answers
1	To connect coaxial to a parallel wire	balun
2	Gain of an isotropic antenna	0 dB
3	What is the term used for an equivalent resistance that would dissipate the same amount?	radiation resistance
4	Resulting from obstruction losses	log normal fading
5	Radiation pattern of a discone	omnidirectional
6	Band of light waves	ultraviolet
7	Which of the following antennas receives signals from all direction in horizontal plane?	vertical marconni antenna
8	What happens to beamwidth?	the beamwdith increases as the gain is increased
9	3:00 PM is a standard time	2100 UTC
10	What is the total resistance of an antenna system?	radiation resistance + ohmic resistance
11	In which crosstalk dBx ????????	1pW
12	How can be antenna efficiency ????????????	by installing a good ground radar system
13	What optical source radiates light in all directions?	lambertian source
14	What is the protocol that is used in transferring files?	X modem
15	What signal to noise ratio for satisfactory TV?	40 dB
87	cable consists of twisted pairs of conductors, each separately insulated	Quad
88	stereophonic FM	30 -53 KHz
89	signal to noise ratio required for satisfactory TV reception	40 dB
90	Start of test for BISYNC	STX
91	Short bit sequence 128 bits	hash
92	rules and description binary	V.1
93	affected by the distance	loudness
94	information about satellite send to earth	TTC
95	if away from source	plane wave
96	measures speed	doppler’s effect
97	measures virtual height of ionosphere	ionosonde
98	sound travels fastest at	solid
16	What is the GPS ???????????????	100meters ,95% of the time
17	According to the nyquist theory the sampling rate is _____	twice the highest frequency
18	It consists of a number of dipoles	broadside array
19	Line of sight mode of propagation	space or direct wave
20	What causes a maximum frequency Vary ???????????????	the amount of radiation received from the sun
21	The low power short range wireless technology	bluetooth
22	What is the insertion loss of connector splices?	0.38dB
23	Which of the following frequency is normally used in safety communication?	2174.5 kHz
24	What determine the ability of a radar?	antenna directivity
25	What is the meaning of velocity factor?	the velocity of the wave divided by the velocity of light
26	For T carrier system, T3 has a bit rate of _____	44.736Mbps
27	A half wave antenna operates at very high efficiency ____	because the conductor resistance is low compared to the radiation resistance
28	Process of a signing pcm codes absolute magnitudes	quantizing
29	What distortion is does not cause by TL characteristics?	spacing bias distortion
30	After IF stages	local oscillator
31	Spot in the visible surface of the sun	sun spot
32	What is the number pins of R232 C?	25
33	What for the ratio of radiation resistance to the total resistance?	antenna efficiency
34	What is the reference tone level for dbm?	-90dBm
35	What is the quantization signal to noise ratio if an 8 bit PCM is used?	50dB
36	Which is space diversity?	two or more antennas operating in the same frequency
37	The lowest layer in the ionosphere	D
38	What causes a interference?	poor front end selectivity
39	Cross modulation in the receiver is eliminated at the ____	detector stage
40	Which of the ff antennas require good grounding?	marconni antenna
41	In an FM receiver which circuit is used amplitude variations	limiter
42	What deviation is measured for an angle?	horizontal
43	What is the minimum propagation delay for stationary satellites?	230 milliseconds
44	A unique character is transmitted at the beginning of each message	asynchronous
45	Ku band	14/11 GHz
46	tv receiver that separates sound	radio detector
47	the TACAN is a nav aid providing ___	bearing and distance indication
48	What is the spectrum of FM signal?	30-50kHz
49	What is the emission designation of single sound reduced carrier signal?	R3E
50	the mid-range frequency range of sound is	256-2048Hz
51	the standard deviation of in transmission loss should not exceed	1dB
52	modem are required to connect	the telephone network will pass DC
53	What kind of impedance 1/8 wavelength TL present to a generator?	an inducting reactance
54	What noise is short duration?	impulse noise
55	What is the channel spacing of ???????????	500Hz
56	How is antenna efficiency computed?	efficiency = radiation resistance divided by total resistance X 100%
57	an absorption loss caused by valence electron	ultraviolet absorption
58	is a device in data transmission to interface a data to analogue	modem
59	What is the most commonly used IF of radar receivers?	30MHz
60	layer that exist only during daylight	F1 layer
61	Frequency spectrum ??????	30-53kHz
62	Attenuates signals that passes frequency below	bandstop
63	skip zone	zone of silence
64	Station in the mobile service not intended to use	land station
65	The letter number designation B8E	independent sideband
66	What is the typical separation between two conductors?	0.635 – 15cm
67	Which of the following pulse modulation is ???????????	EWX ??????????
68	Connecting an antenna electrically add a	coil
69	An ITU-T that deals with the telephone circuits	V series
70	Cause some frequency to be delayed with respect to other frequency	phase shift
71	Occurs when a microwave beam is at point	diffraction
72	The input signal of a TWT	cathode end of a helix
73	An equipment used to measure SWR	reflectometer
74	Is a standard where mobile phone can access to specially tailored internet websites	WAP
75	In what region of the world is sporadic E	equatorial regions
76	A radio communication service used for aeronautical safety navigation	aeronautical fixed service
77	What kind of impedance ¼ wavelength?	a very low impedance
78	Propagation mode microwave	TE
79	How far is the visual carrier of monochrome TV channel?	1.25MHz
80	A helical antenna is used for satellite tracking	circular polarization
81	What is ascending pass for a LEO?	from south to north
82	A properly connected Transmission Line has a ____	SWR as near as 1:1 as possible
83	What is the primary advantage of ?????????????	no transmitted power is wasted in the carrier
84	What device is used in diverting electromagnetic?	waveguide switch
85	A type of underground antenna	hertz antenna
86	A type of array which contains of 1 half wave dipole, 1 reflector and 1 director	Yagi uda
87	What happens to a path wave as it is shorted through the use of loading coils?	decreased
88	What do you call the incident light that have different refractive indeces?	reflection
89	What is the standard test tone used for audio measurements?	1000 Hz
90	Capture effect is most pronounced in what type of emission	FM
91	What is the GPRS uplink rate?	14kbps
92	What is the advantage of Doherty linear?	high efficiency
93	Frequency of VCR control signal	30 Hz
94	A type of microphone which has a permanent magnet	ribbon
95	Block calls delays	Erlang C
96	On a telephone system, the loop is open during ___	on hook condition
97	A telephone line connecting two central offices	trunk
98	The SPL in dB of an auditorium with contemporary music is ___	95 -100

Complete List of Communications Engineering Coaching Materials

Communications Engineering Coaching Materials

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