A. Test 1
1) The ratio of the largest rms value to the smallest value of the voltage in the line is called
a) SWR
b) ISWR
c) VSWR
d) Coefficient of reflection
2) If the same subscriber loop above limits the voice attenuation to a maximum of 6 dB, what is the maximum allowable subscriber loop length, in feet, using the same gauge # 26 telephone wire? Assume a 2.7 dB loss per mile.
a) 20,000 ft
b) 13,900 ft
c) 15,280 ft
d) 11, 733 ft
3) The input is 0.1 W and the network gain is 13 dB, the output is
a) 2.0 W
b) 2.5 W
c) 1.5 W
d) 1.8 W
4) Known as one-tenth of a neper.
a) dB
b) dBm
c) dBp
d) dNp
5) The input impedance of a quarterwave short-circuited transmission line at its resonant frequency is
a) 0 W
b) infinite or an open circuit
c) W
d) 70 W
6) In the preceding problem, calculate the line current.
a) 1.7 A
b) 1.3 A
c) 1.5 A
d.) 1.0 A
7) Determine also the total attenuation of the line in the preceding problem.
a) 2.0 dB
b) 1.5 dB
c) 2.5 dB
d) 1.0 dB
8) What is the maximum subscriber loop length, in ft., of a telephone system if the signaling resistance is 1800 W using a telephone cable pair of gauge # 26 with a loop resistance of 83.5 W per 100 ft. Assume the telephone set resistance is equal to 200 W.
a) 1,516.17 feet
b) 1,916.16 feet
c) 15,300 feet
d) 20,000 feet
9) What is the opposition to the transfer of energy which is considered the dominant characteristics of a cable or circuit that emanates from its physical structure?a) Conductance
b) Resistance
c) Reactance
d) Impedance
10) When load impedance equals to Zo of the line, it means that the load _____ all the power.
a) reflects
b) absorbs
c) attenuates
d) radiates
11) Impedance matching ratio of a coax balun.
a) 1:4
b) 4:1
c) 2:1
d) 3:2
12) Which stands for dB relative level?
a) dBrm
b) dBa
c) dBr
d) dBx
13) Standard test tone used for audio measurement.
a) 800 Hz
b) 300 hz
c) 100 Hz
d) 1000 Hz
14) When VSWR is equal to zero, this means
a) that no power is applied
b) that the load is purely resistive
c) that the load is a pure reactance
d) that the load is opened
15) _________is the ratio of reflected voltage to the forward traveling voltage.
a) SWR
b) VSWR
c) Reflection coefficient
d) ISWR
16) Transmission line must be matched to the load to __________.
a) transfer maximum voltage to the load.
b) transfer maximum power to the load.
c) reduce the load current.
d) transfer maximum current to the load.
B. Test 2
1) Which indicates the relative energy loss in a capacitor?
a) Quality factor
b) Reactive factor
c) Dissipation factor
d) Power factor
2) What is the standard test tone ?
a) 0 dB
b) 0 dBW
c) 0 dBm
d) o dBrn
3) The energy that neither radiated into space nor completely transmitted.
a) Reflected waves
b) Captured waves
c) Incident waves
d) Standing waves
4) Micron is equal to _______ meter.
a) 10-10
b) 10-9
c) 10-6
d) 10-3
5) 1 Angstrom (A) is equal to ___________.
a) 10-3 micron
b) 10-10 m
c) 10-6 micron
d) 10-6 m
6) Why it is impossible to use a waveguide at low radio frequencies?
a) Because the size of the waveguide
b) Due to severe attenuation
c) Due to too much radiation
d) All of these
7) _________ is the transmission and reception of information.
a) Modulation
b) Communication
c) Radiation
d) Emission
8) What is the loss of the circuit in dB if the power ratio of output to input is 0.01?
a) 20
b) –20
c) 40
d) –40
9) Transmission lines are either balanced or unbalanced with respect to
a) negative terminal
b) reference
c) ground
d) positive terminal
10) The standing wave ratio is equal to ______ if the load is properly matched with the transmission line.
a) infinity
b) 0
c) –1
d) 1
11) ____________ is the advantage of the balanced transmission line compared to unbalanced line.
a) Low attenuation
b) Easy installation
c) Low radiation loss
d) Tensile strength
12) ____________ is the method of determining the bandwidth of any processing system.
a) Fourier Series
b) Spectral analysis
c) Frequency analysis
d) Bandwidth analysis
13) What causes the attenuation present in a waveguide?
a) The air dielectric filling the guide
b) The coating of silver inside
c) Losses in the conducting walls of the guide
d) Radiation loss
14) A device that converts a balanced line to an unbalanced line of a transmission line.
a) Hybrid
b) Stub
c) Directional coupler
d) Balun
15) What is the approximate line impedance of a parallel-strip line spaced 1 cm apart with the length of 50 cm?
a) 10 ohms
b) 15 ohms
c) 18 ohms
C. Test 3
1) What is the average power rating of RG-58 C/u?
a) 25 W
b) 50 W
c) 75 W
d) 200 W
2) A coaxial cable used for high temperatures.
a) RG-58C
b) RG-11A
c) RG 213
d) RG-211A
3) If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60 dB?
a) 2
b) 3
c) 4
d) 5
4) You are measuring noise in a voice channel at a –4 dB test point level, the meter reads –73 dBm, convert the reading into dBrnCO.
a) 12
b) 16
c) 18
d) 21
5) The velocity factor of a transmission line
a) deoends on the dielectric constant of the material used
b) increases the velocity along the transmission line
c) is governed by skin effect.
d) is higher for a solid dielectric than for air
6) Impedance inversion can be obtained by
a) a short –circuited stub
b) an open-circuited stub
c) a quarter-wave line
d) a half-wave line
7) Transmission lines when connected to antennas have
a) capacitive load
b) resistive load whose resistance is greater than the characteristic impedance of the line
c) resistive load whose resistance is less than characteristic impedance of the line
d) resistive load at the resonant frequency.
8) One of the following is not a bounded media.
a) Coaxial cable
b) Two-wire line
c) Waveguide
d) Ocean
9) The impedance measured at the input of the transmission line when its length is infinite.
a) Input impedance
b) Open circuit impedance
c) Characteristic impedance
d) Short circuit impedance
10) The following are considered primary line constants except
a) conductance
b) resistance
c) capacitance
d) complex propagation constant
11) The dielectric constant of materials commonly used in transmission lines range from about
a) 1.2 to 2.8
b) 2.8 to 3.5
c) 3.5 to 5.2
d) 1.0 to 1.2
12) Typically, the velocity factor (Vf) of the materials used in transmission lines range from
a) 0.6 to 0.9
b) 0.1 to 0.5
c) 1.0 to 0.9
d) 0.6 to 0.8
13) For an air dielectric two-wire line, the minimum characteristic impedance value is
a) 85 W
b) 83 W
c) 90 W
d) 88 W
14) When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, its input impedance is
a) inductive
b) capacitive
c) resistive
d) equivalent to a parallel resonant LC circuit
15) A transmitter operating at 30 MHz with 4W output is connected via 10 m of RG-8A/U cable to an antenna that has an input resistance of 300 W. Find the reflection coefficient.
a) 0.71
b) 0.77
c) 0.97
d) 0.76
D. Test 4
1) A quarterwave transformer is connected to a parallel wire line in order to match the line to a load of 1000 W. The transformer has a characteristic impedance of 316.23 W. The distance between centers is 4 inches. What id the percentage reduction in the diameter of the line?
a) 85%
b) 83%
c) 86%
d) 90%
2) The concept used to make one Smith chart universal is called
a) ionization
b) normalization
c) rationalization
d) termination
3) What are the basic element of communications system?
a) Source, transmission channel, transmitter
b) Transmitter, receiver, transmission channel
c) Information, transmission channel, receiver
d) Sender and receiver
4) ________ is the transmission of printed material over telephone lines.
a) Internet
b) Data communication
c) Telegraphy
d) Facsimile
5) __________is a continuous tone generated by the combination of the frequencies of 350 Hz and 440 Hz used in telephone sets.
a) DC tone
b) Ringing tone
c) Dial tone
d) Call waiting tone
6) ___________are unidirectional amplifiers having 20-25 decibels gain that are placed about 75 km apart used to compensate for losses along the telephone lines.
a) VF repeaters
b) Loading coils
c) Loop extenders
d) Echo suppressors
7) ___________ is a component in the telephone set that has the primary function of interfacing the handset to the local loop.
a) Resistor
b) Capacitor
c) Varistor
d) Induction coil
8) Pulse dialing has _________rate.
a) 20 pulses/min
b) 10 pulses/min
c) 10 pulses/sec
d) 80 pulses/sec
9) ______ is a telephone wire that connects two central offices.
a) 2-wire circuit
b) Trunk line
c) Leased line
d) Private line
10) The central switching office coordinating element for all cell sites that has cellular processor and cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities.
a) MTSO
b) Cell Site
c) PSTN
d) Trunk line
11) _________in a cellular system performs radio-related functions for cellular site.
a) Switching system
b) Base station
c) Operation and support system
d) Mobile station
12) A technology used to increase the capacity of a mobile phone system.
a) Frequency re-use
b) Cell splitting
c) TDM
d) FDM
13) If the grade of service of a telephone system indicated P=0.05, what does it mean?
a) Completed calls of 5%
b) Lost calls of 5 %
c) Lost calls of 95%
d) Lost calls of 105%
14) ___________ is the out-of-Band signaling between, toll central offices (Bell System Standard).
a) 3,825 Hz
b) 3700 Hz
c) 2,600 Hz
d) 800 Hz
15) In a telephone system, the customer’s telephone directory numbering is from 000 to 999, what is the capacity of a telephone system numbering is from 000 to 999?
a) 100 lines
b) 1000 lines
c) 10,000 lines
d) 100,000 lines
1) If the SWR is infinite, what type of load transmission line has?
a) Purely reactive
b) Purely resistive
c) Purely capacitive
d) Purely inductive
2) Not more than __________digits make up an international telephone number as recommended by CCITT REC.E 161.
a) 8
b) 10
c) 11
d) 12
3) One (1) Erlang is equal to ______________.
a) 360 CCS
b) 36 CCS
c) 3.6 CCS
d) 100 CCS
4) Standard tariff for flat rate telephone service beyond the normal flat rate in that area.
a) WATS
b) OTLP
c) TIP
d) DTWX
5) The standard analog telephone channel bandwidth.
a) 300-3400 Hz
b) 1200 Hz
c) 200-3200 Hz
d) 300-3000 Hz
6) Type of switching in which a pair of wire from the telephone set terminates in a jack and the switch is supervised by an operator.
a) Crossbar switching
b) Manual switching
c) Electronic switching
d) Step-by-step switching
7) Every time when the telephone is idle, the handset is in the ______state.
a) on-hook
b) off-hook
c) busy
d) spare
8) ________ is a component in the telephone set that has the primary function of compensating for the local loop length.
a) Resistor
b) Varistor
c) Capacitor
d) Induction coil
9) What kind of receiver is used in conventional telephone handset?
a) Carbon
b) Electromagnetic
c) Ceramic
d) Capacitor
10) A voice-grade circuit using the PTN has an ideal passband of
a) 0 to 4 Hz
b) 0 to 4 MHz
c) 0 to 4 kHz
d) 0 to 4 GHz
11) __________ is the minimum-quality circuit available using PTN.
a) Basic voice grade (VG)
b) Basic voice channel (VC)
c) Basic voice band (VB)
d) Basic telephone channel
12) Direct distance dialing (DDD) network is called
a) Private-line network
b) PT network
c) Dial-up network
d) Trunk network
13) What is the advantage of sideband?
a) Transmission efficiency is increased
b) Speaker increases his voice resulting in a strengthened signal
c) No dissipation of energy in the balancing network
d) Assure the customer that the telephone is working
14) ___________is a special service circuit connecting two private branch exchanges (PBX).
a) Phantom line
b) Tie trunk
c) Tandem trunk
d) Private line
15) The published rates, regulations and descriptions governing the provision of communications service for public use.
a) Toll rate
b) Tariff
c) Bulk billing
F. Test 6
1) What is the power loss of a telephone hybrid?
a) 1 dB
b) 2 dB
c) 3 dB
d) 6 dB
2) Telephone channel has a band-pass characteristic occupying the frequency range of __________.
a) 300-400 Hz
b) 300-3400 Hz
c) 300-3000 Hz
d) 300-2700 Hz
3) The first Strowger step-by-step switch was used in ____________.
a) 1875
b) 1890
c) 1897
d) 1913
4) What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees?
a) 52 msec
b) 1.25 msec
c) 83.33 msec
d) 26 msec
5) What is the CCITT recommendation for a preparation of loss plan, a variable loss plans and a fixed loss plan?
a) G.133
b) G.141
c) G.132
d) G.122
6) What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 oh/km?
a) 0.838 mm
b) 0.465 mm
c) 1.626 mm
d) 2.159 mm
7) What kind of cell is appropriate for load management, fast moving mobiles and low-usage areas?
a) pico cells
b) micro cells
c) nano cells
d) umbrella cells
8) In cellular networks, standard base station antennas are replaced by ____________.
a) adaptive array
b) flat plate antenna
c) dipole array
d) focused antenna
9) What is the basis of the first generation wireless local loop?
a) Digital Cellular technology
b) Analog Cellular technology
c) PSTN
d) AMPS technology
10) When the calling party hears a “busy” tone on his telephone, the call is considered
a) lost
b) disconnected
c) completed
d) incomplete
11) Short-circuited stubs are preferred to open circuited stubs because the latter are
a) more difficult to make and connect
b) made of a transmission line with a different characteristic impedance
c) liable to radiate
d) incapable of giving a full range of reactances
12) What is the ratio of the reflected voltage to the incident voltage?
a) VSWR
b) ISWR
c) SWR
d) Coefficient of reflection
13) One method of determining antenna impedance.
a) stub matching
b) trial and error
c) Smith chart
d) Quarter-wave matching
14) ______is a single conductor running from the transmitter to the antenna.
a) single-wire line
b) Microstrip
c) Twin-lead
d) Coaxial line
15) Coaxial cable impedance is typically ___________.
a) 150 to 300 W
b) 50 to 75 W
c) 30 to 45 W
d) 300 to 600 W
1) Waveguide becomes compulsory above what frequencies?
a) Above 3 GHz
b) Above 10 kHz
c) At 300 MHz
d) Above 10 GHz
2) Nominal voice channel bandwidth is ____________.
a) 20 to 30 kHz
b) 0 to 3 kHz
c) 4 kHz
d) 55 kHz above
3) Echo suppressors are used on all communications system when the round trip propagation time exceeds _____________.
a) 50 ms
b) 30 ms
c) 100 ms
d) 1 ms
4) A radio transmission line of 300 W impedance is to be connected to an antenna having an input impedance 150 W. What is the impedance of a quarter-wave matching line?
a) 212 W
b) 250 W
c) 200 W
d) 150 W
5) Quarter-wavelength line is used as _________.
a) impedance transformer
b) lecher line
c) transmission line
d) harmonic suppressor
6) The transmission lines which can convey electromagnetic waves only in higher modes is usually called
a) coaxial cable
b) waveguide
c) power lines
d) twisted wire of telephone line
7) Why is nitrogen gas sometimes used in waveguide?
a) To increase the distributed capacitance
b) To keep the waveguide dry
c) To reduce the skin effect at the walls of the guide
d) To raise the guide’s wave impedance
8) The apparent speed of propagation along a waveguide based on the distance between wavefronts along the walls of the guide is called
a) group velocity
b) phase velocity
c) normal velocity
d) abnormal velocity
9) How do you couple in and out of a waveguide?
a) Wrap a coil of wire around one of the waveguide
b) Insertion of an E-probe into the waveguide
c) Insertion of an H-loop into the waveguide
d) Both B and C
10) A rectangular waveguide is operating in the dominant TE10 mode. The associated flux lines are established
a) transversely across the narrow dimension of the waveguide
b) transversely across the wide dimension of the waveguide
c) in the metal walls parallel to the direction of propagation
d) in the metal walls perpendicular to the direction of propagation
11) For dominant mode of a rectangular waveguide, the distance between two instantaneous consecutive positions of maximum field intensity (in a direction parallel to the walls of the waveguide) is referred to as half of the _________.
a) free-space wavelength
b) cut-off wavelength in the wide dimension
c) guide wavelength
d) group wavelength
12) The guide wavelength, lg, in a rectangular waveguide is______.
a) equal to the free-space wavelength at the cut-off frequency
b) equal to the free-space wavelength for the same signal frequency
c) less than the free-space wavelength at the cut-off frequency
d) greater than the free-space wavelength at the same signal frequency
13) Using the TE10 mode, microwave power can only be transmitted in free rectangular guide provided
a) the wider dimension is less than one-half of the wavelength in free space
b) the narrow dimension is less than one-quarter of the wavelength in free space
c) the wide dimension is greater than one-half of the guide wavelength
d) the wide dimension is greater than one-half of the wavelength in free space
14) If the signal frequency applied to a rectangular guide is increased and the dominant mode is employed
a) the free space wavelength, l, is increased
b) the phase velocity, Vf, increased
c) the guide wavelength is increased
d) the group velocity, Vg, is increased
15) If a 6 Ghz signal is applied to a rectangular waveguide and the reflection angle, q, is 20°, what is the value of the guide wavelength, lg.
a) 6.10 cm
b) 5.32 cm
c) 4.78 cm
d) 5 cm
1) The inner dimensions of a rectangular waveguide are 1.75 cm by 3.5 cm. The cut-off wavelength for the dominant mode is
a) 1.75 cm
b) 3.5 cm
c) 7 cm
d) 0.4375 cm
2) A signal whose wavelength is 3.5 cm is being propagated along a guide whose inner dimensions are 2 cm by 4 cm. What is the value of the guide wavelength, lg ?
a) 3.12 cm
b) 3.89 cm
c) 3.57 cm
d) 6.30 cm
3) The frequency range over which a rectangular waveguide is excited in the dominant mode is limited to
a) The difference between the frequency for which the reflection angle, q, is 90° and the frequency for which q is zero.
b) The difference between the frequency for which the free-space wavelength is equal to the cut-off value and the frequency for which the free-space wavelength is equal to the guide wavelength
c) The difference between the frequency at which the cutoff wavelength is twice the narrow dimension
d) None of these
4) If a rectangular waveguide is to be excited in the dominant mode, the E-probe should be inserted
a) at the sealed end
b) at a distance of one quarter-wavelength from the sealed end
c) at a distance of one-half wavelength from the sealed end
d) at a distance of three-quarters of a wavelength from the sealed end
5) A quarter-wave line is connected to an RF generator and is shorted out at the far end. What is the input impedance to the line generator?
a) A low value of resistance
b) A high value of resistance
c) A capacitive resistance which is equal in the value to the line’s surge impedance
d) An inductive resistance which is equal to the value to the line’s surge impedance
6) If the SWR on a transmission line has a high value, the reason could be
a) an impedance mismatch between the line and the load
b) that the line is non-resonant
c) a reflection coefficient of zero at the load
d) that the load is matched to the line
7) If a quarter-wave transmission line is shorted at one end
a) there is minimum current at the shorted end
b) the line behaves as a parallel-tuned circuit in relation to the generator
c) the line behaves as a series-tuned circuit in relation to the generator
d) there is a minimum voltage at the shorted end
8) A 50-ohm transmission line is feeding an antenna which represents a 50 W resistive load. To shorten the line, the length must be
a) any convenient value
b) an odd multiple of a three-quarters a wavelength
c) an odd multiple of half a wavelength
d) an even multiple of a quarter of a wavelength
9) The outer conductor of the coaxial cable is usually grounded
a) at the beginning and at the end of the cable
b) only at the beginning of the cable
c) only at the end of the cable
d) at the middle of the cable
10) A feature of an infinite transmission line is that
a) its input impedance at the line’s surge impedance
b) its phase velocity is greater than the velocity of light.
c) no RF current will be drawn from the generator
d) the impedance varies t different positions on the line
11) When the surge impedance of a line is matched to a load, the line will
a) transfer maximum current to the load
b) transfer maximum voltage to the load
c) transfer maximum power to the load
d) have a VSWR equal to zero
12) A lossless line is terminated by a resistive load which is not equal to the surge impedance. If the value of the reflection coefficient is 0.5, the VSWR is
a) 2
b) 3
c) 4
d) 15
13) Ratio of the mismatch between the antenna and the transmitter power.
a) Standing wave pattern
b) Reflection coefficient
c) SWR
d) Index of refraction
14) Emission designation for a facsimile
a) H3E and A4E
b) R3E and A4E
c) F4E and J3E
d) F3C and A3E
15) Commonly used telephone wire.
a) AWG #19
b) AWG #18
c) AWG #30
d) AWG #33
1) What is the distance traveled by a wave in the time of one cycle?
a) Frequency
b) Hop
c) Wavelength
d) Crest
2) The velocity factor is inversely proportional with respect to the _______.
a) square of the dielectric constant
b) square root of the dielectric constant
c) dielectric constant
d) square root of refractive index
3) ______ is a hollow structure that has no center conductor but allows waves to propagate
a) Waveguide
b) Hybrid
c) Pipe
d) Directional coupler
4) To connect a coaxial line to a line to a parallel wire line,________ is used.
a) hybrid circuit
b) balun
c) directional coupler
d) quarter-wave transformer matching circuit
5) What length for which the input power has been halved for a transmission line with an attenuation of 6 dB/km?
a) 1.5 km
b) 0.5 km
c) 63 km
d) 2 km
6) In a waveguide, _______ is a specific configuration of electric and magnetic fields that allows a wave to propagate.
a) set-up
b) coupler
c) channel
d) mode
7) A rectangular waveguide has dimensions of 3 cm x 5 cm. What is the dominant mode cut-off frequency?
a) 2 GHz
b) 3 GHz
c) 2.5 GHz
d) 3.5 GHz
8) _______ are transmission lines which can convey electromagnetic waves only in higher order modes?
a) Coaxial cable
b) Twisted pairs of telephone wire
c) Power cables
d) Waveguide
9) The amount of uncertainty in a system of symbols is also called
a) bandwidth
b) loss
c) entropy
d) quantum
10) The twists in twisted wire pairs
a) reduced electromagnetic interference
b) occur at a 30 degree angle
c) eliminate loading
d) were removed due to cost
11) An example of a bounded medium is
a) coaxial cable
b) waveguide
c) fiber-optic cable
d) all of the these
12) Loading means the addition of
a) resistor
b) capacitor
c) bullet
d) inductance
13) What is the most commonly used transmission line for high frequency application?
a) two-wire balance line
b) Single wire
c) Three-wire line
d) Coaxial
14) The characteristic impedance of a transmission line does not depend upon its
a) length
b) conductor diameter
c) conductor spacing
d) dielectric material
15) One of the following is not a common transmission line impedance.
a) 50 W
b) 75 W
c) 120 W
d) 300 W
1) For maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line Zo, and the load impedance , ZL, should be
a) Zo = ZL
b) Zo > ZL
c) Zo <>L
d) Zo = 0
2) The mismatch between antenna and transmission line impedance cannot be corrected for by
a) using LC matching network
b) adjusting antenna length
c) using a balun
d) adjusting the length of transmission line
3) __________is a pattern of voltage and current variation along a transmission line not terminated in its characteristic impedance.
a) an electric field
b) radio waves
c) standing waves
d) a magnetic field
4) Which is the desirable SWR on a transmission line?
a) 0
b) 1
c) 2
d) infinity
5) A 50 W coax is connected to a 73-W antenna. What is the SWR?
a) 0.685
b) 1
c) 1.46
d) 2.92
6) What is the most desirable reflection coefficient?
a) 0
b) 0.5
c) 1
d) infinity
7) What is the ratio expressing the percentage of incident voltage reflected on a transmission line ?
a) Velocity factor
b) Standing-wave ratio
c) Reflection coefficient
d) Line efficiency
8) The minimum voltage along a transmission line is 260 V, while the maximum is 390 V, the SWR is
a) 0.67
b) 1.0
c) 1.2
d) 1.5
9) One meter is one wavelength at a frequency of
a) 150 MHz
b) 164 MHz
c) 300 MHz
d) 328 MHz
10) At very high frequencies, transmission line act as
a) tuned circuits
b) antennas
c) insulators
d) resistors
11) A shorted quarter-wave line at the operating frequency acts like a/an
a) capacitor
b) inductor
c) series resonant circuit
d) parallel resonant circuit
12) A shorted half-wave line at the operating frequency acts like a/an
a) capacitor
b) inductor
c) series resonant circuit
d) parallel resonant circuit
13) A medium least susceptible to noise?
a) Shielded pair
b) Twisted pair
c) Fiber-optic
d) Coaxial
14) A medium most widely in LANs?
a) Parallel-wire line
b) Twisted pair
c) Fiber-optic cable
d) Coaxial
15) The most commonly used transmission line in television system.
a) Parallel-wire line
b) Coaxial cable
c) Waveguide
d) Open-wire with ceramic supports
1) The impedance of a TV transmission line depends on several factors. Which is not one of those factor?
a) Diameter
b) Length of the wire
c) Dielectric material
d) Separation between conductors
2) DC blocks are used in coaxial transmission line for the purpose of
a) passing DC while blocking AC
b) passing AV voltage but prevent DC
c) preventing AC voltage from reaching the pre-amplifier
d) preventing AC power supply voltage from being shorted by a balun or band splitter
3) ___________is a type of interference caused by off-air TV channels 2 and 4 plus a satellite operating on channel 3.
a) Adjacent channel interference
b) Ghost
c) Co-channel interference
d) Crosstalk
4) Dithering (in TVRO communications) is a process for
a) reducing the effect of noise on the TVRO video signal
b) centering the video fine tuning on TVRO channels
c) moving the feedhorn rotor to the precise angle
d) moving the actuator exactly onto the desired satellite beam
5) A network that has an input of 75 dB and an output of 35 dB. The loss of the network is ____________.
a) –40 dB
b) 40 dB
c) 40 dBm
d) –40 dBm
6) Important useful quantities describing waveforms.
a) Time and frequency
b) Voltage an current
c) Frequency and Voltage
d) Power and frequency
7) Halving the power means
a) 6 dB gain
b) 3 dB loss
c) 3 dB gain
d) 6 dB loss
8) One neper (Np) is how many decibels?
a) 8.866
b) 8.686
c) 8.688
d) 8.868
9) A signal is amplified 100 times in power. The dB gain is
a) 20 dB
b) 119 dB
c) 15 dB
d) 25 dB
10) Which of the following is used to measure SWR?
a) Spectrum analyzer
b) Reflectometer
c) Oscilloscope
d) Multimeter
11) 214-056 twin lead which is common used for TV lead-in has a characteristic impedance of
a) 52 W
b) 75 W
c) 600 W
d) 300 W
12) What is the characteristic impedance of a transmission line which is to act as a quarterwave matching transformer between a 175 W transmission line and 600 W load?
a) 300.04 W
b) 324.04 W
c) 310.04 W
d) 320.04 W
13) What is the EIRP in dBW of a 50 dB antenna connected to transmitter with an output of 10 kW through a transmission line with a loss of 5 dB?
a) 85 dBW
b) 955 dBW
c) 90 dBW
d) 80 dBW
14) A coaxial cable is a good example of a/an
a) unbounded medium
b) transmission channel
c) non-metallic medium
d) bounded medium
15) If a quarterwave transformer is required to match a 180 W load to a transmission line with an impedance of 300 W, what should be the charcteristic impedance of the matching transformer? Assume that the matching transformer is to be connected directly to the load.
a) 180 W
b) 232 W
c) 300 W
d) 480 W
