Description : Signals with a frequency between 2 MHz and 30 MHz use ______ propagation. A) ground B) sky C) line-of-sight D) none of the above
Last Answer : sky
Description : Signals with a frequency below 2 MHz use _______ propagation. A) ground B) sky C) line-of-sight D) none of the above
Last Answer : ground
Description : ECE Board Exam March 1996 When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ________ wave. A. space or direct B. ground C. surface D. sky
Last Answer : A. space or direct
Description : The VLF and LF bauds use .............. propagation for communication. (A) Ground (B) Sky (C) Line of sight (D) Space
Last Answer : Answer: A Explanation: VLF (Very Low Frequency) LF (Low Frequency) In general there are three type of propagation.1.Ground Propagation 2.Sky propagation 3.Line-of-sight propagation ... portion of the atmosphere. These low-frequency signals travel in all directions from the transmitting antenna.
Description : Tropospheric scatter is a method of sky wave propagation for which of the following frequency bands? A. 300 kHz to 3 MHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 300 MHz to 3 GHz
Last Answer : D. 300 MHz to 3 GHz
Description : Which of the following frequency bands is best suited for sky wave propagation? A. 30 to 300 kHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 3 GHz to 30 GHz
Last Answer : B. 3 MHz to 30 MHz
Description : Frequency of sky waves is A. less then 3 MHzB. more than 3 MHz C. less than 2 MHz D. exactly 2 MHz
Last Answer : . more than 3 MHz
Description : What frequency range is used for FM radio transmission? A. Very Low Frequency : 3 kHz to 30. kHz B. Low Frequency :30 kHz to 300 kHz C. High Frequency :3 MHz to 30 MHz D. Very High Frequency : 30 MHz to 300 MHz E. None of the above
Last Answer : Very High Frequency : 30 MHz to 300 MHz
Description : Thegroundwave eventuallydisappears, as onemoves awayfromthetransmitter, because of a. interference from the sky wave b. loss of line-of-sight conditions c. maximumsingle-hop distance limitation d. tilting
Last Answer : d. tilting
Description : Which of the following frequency bands is best suited for ground wave propagation? A. 30 to 300 kHz B. 300 kHz to 3 MHz C. 3 MHz to 30 MHz D. 30 MHz to 300 MHz
Last Answer : A. 30 to 300 kHz
Description : A satellite receives an uplink frequency of _______ MHz from a ground station of 3700 MHz. A. 8150 MHz B. 1475 MHz C. 2225 MHz D. 5925 MHz
Last Answer : D. 5925 MHz
Description : ___ cable can carry signals ofhigher frequency ranges than_____ cable. A) Twisted-pair; fiber-optic B) Coaxial; fiber-optic C) Coaxial; twisted-pair D) none of the abov
Last Answer : Coaxial; twisted-pair
Description : Before data can be transmitted, they must be transformed to________. A) periodic signals B) electromagnetic signals C) aperiodic signals D) low-frequency sine waves
Last Answer : electromagnetic signals
Description : Demodulation is the process of A. converting digital signals toanalog signals B. converting analogsignals todigital signals C. combining many low speed channels into onehigh speed channel D. dividing the high-speed signals into frequency bands E. None of the above
Last Answer : converting analogsignals todigital signals
Description : The absolute value of a signal's highest intensity is called………. A. Peak Amplitude B. Frequency C. Phase D. Both a and c
Last Answer : A. Peak Amplitude
Description : What is the name of the new color laptop computer which is powered by a 386 processor at 33 MHz and is built by Epson? a. AX3/33 b. NEC-20 c. Magnum 2000 d. HCL-3000
Last Answer : AX3/33
Description : What is the bandwidth ofa signal that ranges from 1 MHz to4 MHz? A) 4 MHz B) 1 KHz C) 3 MHz D) none of the above
Last Answer : 3 MHz
Description : A periodic signal completes onecycle in 0.001 s. What is thefrequency? A) 1 Hz B) 100 Hz C) 1 KHz D) 1 MHz
Last Answer : 1 KHz
Description : In ________, we combine signals from different sources to fit into a larger bandwidth. A) spread spectrum B) line coding C) block coding D) none of the above
Last Answer : spread spectrum
Description : Modulation is theprocessof A. converting analogsignals todigital signals B. converting digital signals toanalog signals C. Multiplexing various signals intohigh speed line signals D. performing data encryption
Last Answer : converting digital signals toanalog signals
Description : Demodulation is aprocessof A. converting analog to digital signals B. converting digital to analogsignals C. multiplexing various signals intoone high speed line signals D. performing data description
Last Answer : converting analog to digital signals
Description : What is the optimum length for a half-wave aerial that requires to transmit and receive 1 MHz signals?
Last Answer : An aerial length of 750 metres is required
Description : How many voice signals (4 kHz max.) would fit into a 5 MHz spectrum? A. 1250 B. 500 C. 1000 D. 1500
Last Answer : A. 1250
Description : Which one of the following statements is correct regarding the GPS satellites? (A) The nominal altitude is about 20,200 km (B) The inclination of axis satellite is 55° (C) The satellite transmits two L band signals (L1 with 1575.42 MHz and L2 with 1276.6 MHz) (D) All of these
Last Answer : Answer: Option D
Description : When making a blind transmission you should: a. Transmit the message twice b. Transmit each word twice c. Repeat the message on 121.5 MHz d. Wait for visual signals
Last Answer : a. Transmit the message twice
Description : What is the maximum line-of-sight distance between a paging antenna 250 ft high and a pager receiver 3.5ft of the ground? A. 25 km B.25mi C. 70.73 km D. 70.73 mi
Last Answer : B.25mi
Description : The line of sight is kept as high above ground surface as possible to minimise the error in the observed angles due to (A) Shimmering (B) Horizontal refraction (C) Vertical refraction (D) Both shimmering and horizontal refraction
Last Answer : (D) Both shimmering and horizontal refraction
Description : What is the phase coefficient in radians per unit length of a transmission line at the frequency of 10 MHz if the velocity of propagation is 2.5x108 m/s? A. 0.25 B. 2.5 C. 0.35 D. 3.5
Last Answer : A. 0.25
Description : Assume a frequency of 4 MHz, determine the phase shift offered by the line in the above problem. A. 108.5˚ B. 106.5˚ C. 115.5˚ D. 166.5˚
Last Answer : D. 166.5˚
Description : If the operating frequency is 450 MHz what length of a pair of conductors is considered to be a transmission line? A. 2.19 ft B. 2.19 m C. 0.219 ft D. 0.219 m
Last Answer : C. 0.219 ft
Description : Which of the following statements is not true with respect to microwaves? (A) Electromagnetic waves with frequencies from 300 GHz to 400 THz. (B) Propagation is line-of-sight. (C) Very ... waves cannot penetrate walls. (D) Use of certain portions of the band requires permission from authorities.
Last Answer : (A) Electromagnetic waves with frequencies from 300 GHz to 400 THz.
Description : In one-point perspective what is the line called that separates the ground and sky?
Last Answer : The Horizon.
Description : Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus
Last Answer : EPROM
Description : The process of converting analog signals into digital signals so they can be processed by a receiving computer is referred to as: a. modulation b. demodulation c. synchronizing d. digitising
Last Answer : digitising
Description : In astar-topology Ethernet LAN, _______ is just a point where the signals coming from different stations collide; it is thecollision point. A) An activehub B) A passivehub C) either (a)or (b) D) neither (a) nor (b)
Last Answer : A passivehub
Description : A traditional cable TV network transmits signals ______. A) upstream B) downstream C) upstream and downstream D) none of the above
Last Answer : downstream
Description : Data from a computer are_______; the local loop handles _______ signals. A) analog; analog B) analog; digital C) digital; digital D) digital; analog
Last Answer : digital; analog
Description : ______ cables carry data signals in the form of light. A) Coaxial B) Fiber-optic C) Twisted-pair D) none of the above
Last Answer : Fiber-opti
Description : _____ isan analog multiplexing technique to combine optical signals. A) FDM B) TDM C) WDM D) None of the above
Last Answer : WDM
Description : ______ can be applied whenthe bandwidth of a link (in hertz) is greater than the combined bandwidths of the signals to be transmitted. A) TDM B) FDM C) Both (a)or (b) D) Neither (a) or (b)
Last Answer : FDM
Description : Which multiplexing technique involves signals composed of light beams? A) FDM B) TDM C) WDM D) none of the above
Description : Which multiplexing technique transmits digital signals? A) FDM B) TDM C) WDM D) None of the above
Last Answer : TDM
Description : Which multiplexing technique transmits analog signals? A) FDM B) TDM C) WDM D) (a) and (c)
Last Answer : (a) and (c)
Description : _______ signals canhave only alimited number of values. A) Analog B) Digital C) (a) or (b) D) None of the above
Last Answer : Digital
Description : _____ signals can have an infinite number of values ina range. A) Analog B) Digital C) (a) or (b) D) None of the above
Last Answer : Analog
Description : Signals can be ________. A) analog B) digital C) either (a)or (b) D) neither (a) nor (b)
Last Answer : either (a)or (b)
Description : _______ allow insertion and extraction of signals. A) regenerators B) ADMs C) STS multiplexer/demultiplexers D) none of the above
Last Answer : regenerators
Description : SDH hasdefined ahierarchy of signals called ________. A) STSs B) STMs C) either (a) or (b) D) neither (a) nor (b)
Last Answer : STSs
Description : Compared to analog signals, digital signals A. allow faster transmission B. are moreaccurate C. both (a)and (b) D. All of theabove E. None of the above
Last Answer : both (a)and (b)