Description : What is the purpose of swept-frequency testing?
Last Answer : To determine various characteristics of a component, piece of equipment, or system over its operational frequency range
Description : Why is the physical length of a coaxial cable transmission line shorter than its electrical length? A. Skin effect is less pronounced in the coaxial cable B. RF energy moves slower along the ... higher in the parallel feed line D. The characteristic impedance is higher in the parallel feed line
Last Answer : B. RF energy moves slower along the coaxial cable
Description : Transmission lines when connected to antenna have A. capacitive load B. resistive load whose resistance is less than characteristics impedance C. resistive load at the resonant frequency D. resistive load whose resistance is greater than the characteristic impedance of the line
Last Answer : C. resistive load at the resonant frequency
Description : The beat frequency in a swept-frequency transmitter provides what contact information?
Last Answer : Range.
Description : What symbol is used to designate the characteristic impedance of a line, and what two variables does it compare?
Last Answer : Z0 and it is the ratio of E to I at every point along the line.
Description : A transmission line of unknown impedance is terminated with two different resistances, and an SWR is measured each time. With a 75 Ω termination, the SWR measures 1.5. With a 300 Ω termination, it measures 2.67. What is the impedance of the line? A. 100 Ω B. 212 Ω C. 300 Ω D. 112 Ω
Last Answer : D. 112 Ω
Description : Characteristics impedance of a transmission line is the impedance measured at the ___________ when its length is infinite. A. input B. shorted end of the line C. output D. midsection
Last Answer : A. input
Description : The actions of the tr and atr circuits depend on the impedance characteristics of what length of transmission line?
Last Answer : Quarter-wavelength section
Description : What is the result of an impedance mismatch between a receiver or transmitter and its transmission line or antenna?
Last Answer : High vswr, which equates to poor reception or a loss of power output.
Description : When a transmission line has a load impedance same as that of the characteristic impedance, the line is said to be a) Parallel b) Perpendicular c) Polarized d) Matched
Last Answer : Ans: D
Description : What is the input impedance of a transmission line if its characteristic impedance is 300 Ω and the load is 600 Ω? Assume a quarter wavelength section only. A. 150 kΩ B. 150 mΩ C. 150 Ω D. 2 Ω
Last Answer : C. 150 Ω
Description : What is the meaning of the term velocity factor of a transmission line? A. The ratio of the characteristic impedance of the line to the terminating impedance B. The index of shielding for coaxial ... The velocity of the wave on the transmission line divided by the velocity of light in a vacuum.
Last Answer : D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum.
Description : What is the meaning of the term velocity factor of a transmission line? A. The index of shielding for coaxial cable B. The velocity of the wave on the transmission line multiplied by the velocity of ... The velocity of the wave on the transmission line divided by the velocity of light in a vacuum
Last Answer : D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum
Description : Referred to the dielectric constant of a transmission line material. A. Inductance and capacitance B. Velocity factor C. Characteristic impedance D. Propagation velocity
Last Answer : B. Velocity factor
Description : If the terminating impedance is exactly equal to the characteristic impedance of the transmission line the return loss is ___________. A. zero B. one C. infinite D. None of these
Last Answer : C. infinite
Description : Short-circuited stubs are preferred to open-circuited stubs because thelatter are a. more difficult to make an connect b. made of a transmission line with a different characteristic impedance c. liable to radiate
Last Answer : c. liable to radiate
Description : A load of 200 ohm is used to match 300 ohm transmission line to achieve SWR=1. Find out the required characteristic impedance of a quarter of a quarter wave transformer connected directly to the load.
Last Answer : Solution :
Description : The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.
Last Answer : The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.
Description : The input impedance of a short circuited loss less transmission line of characteristic impedance 50 Ohm is
Last Answer : Capacitive
Description : A transmission line is terminated at its characteristic impedance. The reflection coefficient is (a) 1 (b) –1 (c) 0 (d) ∞
Last Answer : A transmission line is terminated at its characteristic impedance. The reflection coefficient is 0
Description : What is the range of the characteristic impedance of lines used in actual practice?
Last Answer : Between 50 and 600 ohms.
Description : The impedance Z offered by transmission line for a travelling wave which damps out the low frequency oscillation rapidly is also called
Last Answer : The impedance Z offered by transmission line for a travelling wave which damps out the low frequency oscillation rapidly is also called Both surge and natural impedances.
Description : Due to scan geometry of a satellite sensor: (A) The off-nadir resolution is degraded (B) The ground distance swept by the senor, IFOV is proportional to sec2 of scan measured from the nadir (C) The details towards the edge of the scan get compressed (D) All of these
Last Answer : Answer: Option D
Description : What characteristic is determined by the time required for a voltage wave to travel from the input end of an artificial transmission line to the output end and back again?
Last Answer : Pulse width
Last Answer : Pulse width.
Description : What happens when a frequency meter is adjusted to the frequency of the signal being measured?
Last Answer : Power is absorbed by the frequency meter cavity; and a pronounced dip in power, at the output, will be observed.
Description : What is the impedance of a crystal at its resonant frequency when it is used in the series mode?
Last Answer : Minimum.
Description : What is the impedance of a crystal at its resonant frequency when it is used in the parallel mode?
Last Answer : Maximum
Description : What happens to the impedance of interelectrode capacitance as frequency increases?
Last Answer : Impedance decreases.
Description : What electrical quantity is measured by a watt-hour meter?
Last Answer : Energy.
Description : What electrical quantity is measured by a wattmeter?
Last Answer : Power
Description : What electrical quantity is measured by an ohmmeter?
Last Answer : Resistance.
Description : What electrical quantity is measured by a voltmeter?
Last Answer : Voltage.
Description : When troubleshooting most electronic circuits, 'loading effect' can be minimized by using a voltmeter with a/an ___________________. A. input impedance much greater than the impedance across which the voltage ... sensitivity of less than 1000 ohms/volt D. sensitivity of more than 1000 volts/ohm
Last Answer : Answer: A
Description : What is the term for the ratio of actual velocity at which a signal travels through a line to the speed of light in a vacuum? A. Velocity factor B. Characteristic impedance C. Surge impedance D. Standing wave ratio
Last Answer : A. Velocity factor
Description : What is the characteristic impedance of a coaxial line with the following data: inner diameter = 0.2 in., center conductor diameter = 0.06 in., insulation = Teflon. A. 200Ω B. 75Ω C. 50Ω D. 150Ω
Last Answer : C. 50Ω
Description : What is the characteristic impedance of a two-wire line with the following data: diameter = 0.023in., spacing =0.5 in., insulation = PE.? A. 300Ω B. 250Ω C. 305Ω D. 301Ω
Last Answer : D. 301Ω
Description : A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is: (1) 4000 Ω (2) 400 Ω (3) 40 Ω (4) 4 Ω
Last Answer : A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is: 400 Ω
Description : A loss less line of characteristic impedance Z0 is terminated in pure reactance of –jZ0 value. VSWR is (1) 10 (2) 2 (3) 1 (4) Infinity
Last Answer : A loss less line of characteristic impedance Z0 is terminated in pure reactance of –jZ0 value. VSWR is Infinity.
Description : The transmission of still images over an electrical communications system is known as what?
Last Answer : Facsimile.
Description : The presence of standing waves on a transmission line is the result of A. a high level of attenuation on the line. B. terminating the line by a resistive load equal in value to the surge impedance ... input power to below its critical level. D. an impedance mismatch between the load and the line.
Last Answer : D. an impedance mismatch between the load and the line.
Description : Which of the following characterizes a properly terminated transmission line? A. The line loss is minimum. B. The standing wave ratio is minimum. C. The input impedance is twice the load impedance. D. The standing wave ratio is one.
Last Answer : D. The standing wave ratio is one.
Description : What determines the velocity factor in a transmission line? A. The termination impedance B. The line length C. Dielectrics in the line D. The center conductor resistivity
Last Answer : C. Dielectrics in the line
Description : What is included in the total resistance of an antenna system? A. Radiation resistance plus space impedance B. Radiation resistance plus transmission resistance C. Transmission line resistance plus radiation resistance D. Radiation resistance plus ohmic resistance
Last Answer : D. Radiation resistance plus ohmic resistance
Description : Which of the following is not common transmission line impedance? A. 50 ohms B. 120 ohms C. 75 ohms D. 650 ohms
Last Answer : B. 120 ohms
Description : What determines the velocity factor in transmission line? A. The center conductor resistivity B. Dielectrics in the line C. The termination impedance D. The line length
Last Answer : B. Dielectrics in the line
Description : Termination means A. result of disconnecting a line from a transmitter B. result of cutting both ends of a conductor C. looking back impedance of a line with no load D. load connected to the output end of a transmission line
Last Answer : D. load connected to the output end of a transmission line
Description : ECE Board Exam March 1996 The characteristics impedance of a transmission line does not depend upon its ________. A. conductor spacing B. conductor diameter C. length D. conductor radius
Last Answer : C. length
Description : The minimum impedance of a 75 ohm transmission line with a SWR of 2.5 is a) 100 b) 50 c) 25 d) 30
Last Answer : d) 30
Description : The maximum impedance of a 50 ohm transmission line with SWR of 3 is a) 50/3 b) 3/50 c) 150 d) 450
Last Answer : c) 150