Description : Best choice of transmission line component to couple a coaxial line to a parallel-wire line A. Shorting B. Balun C. Slotted line D. Directional coupler
Last Answer : B. Balun
Description : Referred to as a ferrite device that can be used in lieu of a duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna. A. Isolator B. Circulator C. Coupler D. Diode.
Last Answer : B. Circulator
Description : Curl cannot be employed in which one of the following? a) Directional coupler b) Magic Tee c) Isolator and Terminator d) Waveguides
Last Answer : d) Waveguides
Description : To couple a coaxial line to parallel line, it is better to use a ______. A. Slotted line B. Quarter-wave transformer C. Directional Coupler D. Balun
Last Answer : D. Balun
Description : To connect coaxial line to a parallel-wire _________ is the best to use. A. directional coupler B. quarter-wave transformer C. balun D. slotted line
Last Answer : C. balun
Description : When is it useful to refer to an isotropic radiator? A. When comparing the gains of directional antennas B. When testing a transmission line for standing wave ratio C. When (in the northern ... ) directing the transmission in a southerly direction D. When using a dummy load to tune a transmitter
Last Answer : A. When comparing the gains of directional antennas
Description : Radio wave concentration in the direction of the signal emitted by a directional antenna. A. Back lobe radiation B. Side lobe radiation C. Major lobe radiation D. Transmitted signal
Last Answer : C. Major lobe radiation
Description : Circuit used to amplify the optical signal in fiber optics communications links. A. Attenuator B. Optical repeater C. Optical amplifier D. Generator
Last Answer : B. Optical repeater
Description : It is useful to refer to an isotropic radiator. A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio C. when (in the northern hemisphere) directing the transmission D. when using a dummy load to tune a transmitter
Last Answer : A. when comparing the gains of directional antennas
Description : What is the device used in fiber optic communication which consist of a receiver transmitter use to clean up and amplify digital data moving in one direction and another in the opposite direction? A. Optic compressors B. Optic retarders C. Optic isolator D. Optic regenerators
Last Answer : D. Optic regenerators
Description : What is meant by antenna gain? A. The final amplifier gain minus the transmission line losses (including any phasing lines present) B. The ratio of the amount of power produced by the antenna ... D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Last Answer : D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Description : Write working of opto coupler as an isolator.
Last Answer : Optocoupler is as shown in fig. it consist of LED as an light source and phototransistor act as light detector. When input pulse is applied LED turns ON.Light emitted by LED focused on CB ... starts flowing.As input pulse reduces to zero LED turns OFF collector current becomes zero.
Description : To couple a coaxialline toa parallel-wire line,itisbesttouse a a. slotted line b.balun c. directional coupler d. quarter-wave transformer
Last Answer : b.balun
Description : Fortransmission-line loadmatchingover a range offrequencies,itisbesttouse a a. balun b. broadband directional coupler c. double stub d. single stub of adjustable position
Last Answer : c. double stub
Description : What circuit is responsible in activating and deactivating adjacent antenna elements in a mobile satellite array? A. Radial divider B. Divider/combiner C. Radial combiner D. Radial multiplexer
Last Answer : A. Radial divider
Description : How can intermodulation interference between two transmitters in close proximity reduced or eliminated? A. Through installing a band-pass filter in the antenna feed line B. Through installing terminated circulator ... high driving power D. By installing a low-pass filter in the antenna feed line
Last Answer : A. Through installing a band-pass filter in the antenna feed line
Description : A means of beyond the line-of-sight propagation of microwave signal. A. Space wave B. Microwave link C. Troposcatter D. Point-to-point
Last Answer : C. Troposcatter
Description : A device that reduces the intensity of light in fiber optics communication systems. A. Reducer B. Quality factor C. Optical attenuator D. Compressor
Last Answer : C. Optical attenuator
Description : ECE Board Exam November 1996 What is the applied power if a thermal RF wattmeter is connected to a transmitter through a variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation is used. A. 4.656 watts B. 2.656 watts C. 3.656 watts D. 2.856 watts
Last Answer : B. 2.656 watts
Last Answer : A. PAM
Description : What happens to reflected energy that enters a directional coupler that is designed to sample incident energy?
Last Answer : . The reflected energy adds at the absorbent material and is absorbed.
Description : in a directional coupler that is designed to sample the incident energy, what happens to the two portions of the wavefront when they arrive at the pickup probe?
Last Answer : The wavefront portions add.
Description : What is the purpose of the absorbent material in a directional coupler?
Last Answer : Absorb the energy not directed at the pick-up probe and a portion of the overall energy
Description : How far apart are the two holes in a simple directional coupler?
Last Answer : 1/4 wavelength.
Description : What is the primary purpose of a directional coupler?
Last Answer : Sampling energy within a waveguide.
Description : Describe a directional coupler.
Last Answer : A fiber optic coupler that prevents the transfer of power between input fibers.
Description : Describe the working of directional coupler with neat diagram.
Last Answer : Directional couplers are devices that will pass signal across one path while passing a much smaller signal along another path. One of the most common uses of the directional coupler is to ... . The frequency determines the separation of the two holes as a fraction of the wavelength.
Description : In a directional coupler: (1) Isolation (dB) equals coupling plus directivity (2) Coupling (dB) equals isolation plus directivity (3) Directivity (dB) equals isolation plus coupling (4) Isolation (dB) equals (coupling) (directivity)
Last Answer : In a directional coupler: Isolation (dB) equals coupling plus directivity.
Description : The input signal of a travelling wave tube is introduced at A. Cathode B. Anode C. Cathode end of the helix D. Collector end of the helix
Last Answer : C. Cathode end of the helix
Description : The earth's gravitational force field is said to be conservative force field because a.The work acted by the earth's gravitational field on a particle is independent on the path traced out by ... directional component always acting normal to a body e.The value of gravitational force rise is fixed
Last Answer : a. The work acted by the earth's gravitational field on a particle is independent on the path traced out by the particle
Description : A quarter wavelength devices made of crystalline calcite that changes polarization in the optic fiber communication. A. Isolator B. Retarder C. Polarizer D. Filters
Last Answer : B. Retarder
Description : What is the propagation velocity of a signal in a transmission line whose inductance and capacitance are 5μH/m and 20μF/m respectively? A. 100x103 m/s B. 100 m/s C. 10x103 m/s D. 100x106 m/s
Last Answer : A. 100x103 m/s
Description : A pair of current-carrying conductors is not considered a transmission line unless it is at least ___ λ long at the signal frequency. A. 0.1 B. 0.3 C. 0.2 D. 0.4
Last Answer : A. 0.1
Description : Determine the dB gain of a receiving antenna which delivers a microvolt signal to a transmission line over that of an antenna that delivers a 20 microvolt signal under identical circumstances. A. 10 dB B. 6 dB C. 3 dB D. 8 dB
Last Answer : B. 6 dB
Description : Which of the following is not a common microwave application? A. Radar B. Data transmission C. Space communications D. Mobile radio
Last Answer : D. Mobile radio
Description : This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km. A. Troposcatter B. Ionospheric scatter C. Ducting D. Microwave
Last Answer : B. Ionospheric scatter
Description : Type of transmission path that permits communication in the frequency range from 30 to 60 MHz and over distances form about 1000 to 2000 km. A. Ducting B. Ionospheric scatter C. Microwave D. Troposcatter
Description : It is a measure of the microwave power radiated from an antenna as a function of angular direction from the antenna axis. A. Antenna pattern B. Polarization C. Beamwidth D. Sidelobes
Last Answer : C. Beamwidth
Description : Which of the following devices will receive voltage surge first travelling on the transmission line ? (a) Lightning arresters (b) Relays (c) Step-down transformer (d) Switchgear
Last Answer : (a) Lightning arresters
Description : Which one is an antenna coupling unit? A. Coupler B. Diplexer C. Lecher wire D. Duplexer
Last Answer : B. Diplexer
Description : Not a reason for the use of an antenna coupler. A. To make the antenna look resistive B. To provide the output amplifier with the correct load impedance C. To discriminate against harmonics D. To prevent re-radiation of the local oscillator
Last Answer : D. To prevent re-radiation of the local oscillator
Description : A device that connects two dissimilar networks and performs the protocol conversion. A. Gateway B. Coupler C. Transformer D. Converter
Last Answer : A. Gateway
Description : What is an opto-coupler IC?
Last Answer : Opto-coupler IC is a combined package of a photo-emitting device and a photosensing device.Examples for opto-coupler circuit : LED and a photo diode, LED and photo transistor, LED and Darlington. Examples for opto-coupler IC : MCT 2F , MCT 2E .
Description : To measure incident power, you must rotate the coupler detector of the wattmeter so that the arrow indicating power flow points toward which end of the transmission line?
Last Answer : Load.
Description : Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. AF amplifier B. Antenna C. Detector D. Crystal
Last Answer : B. Antenna
Description : What is the common up-converter and down-converter IF for microwave communications? A. 60 MHz B. 80 MHz C. 120 MHz D. 70 MHz
Last Answer : D. 70 MHz
Description : A microwave link between the earth station and the down-town terminal. A. STL B. Uplink C. Downlink D. Terrestrial link
Last Answer : D. Terrestrial link
Description : The series of periodically recurrent pulses is modulated in amplitude by the corresponding instantaneous samples. A. PFM B. PWM C. PDM D. PAM
Last Answer : D. PAM
Description : A waveguide passive component that brings a smooth change in the direction of axis maintained perpendicular to the plane of polarization? A. L bend B. H bend C. T bend D. X bend
Last Answer : B. H bend
Description : A disadvantage of using a trap antenna. A. It will radiate harmonics B. It can only be used for single-bad operation C. It is too sharply directional at lower frequencies D. It must be neutralized
Last Answer : A. It will radiate harmonics