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TRANSMISSION LINES > 300 QUESTION BOARD EXAM REVIEWER PART1 > Flashcards

300 QUESTION BOARD EXAM REVIEWER PART1 Flashcards

1
Q

What is the opposition to the transfer of energy, which is considered the dominant characteristic of a cable or circuit that emanates from its physical structure?

A

Impedance

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2
Q
  1. When load impedance is equal to characteristic impedance of the line, it means that the load _____ all the power.
A

Absorbs

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3
Q
  1. Impedance matching ratio of a coax balun (balancing unit).
A

4:1

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4
Q

Which stands for dB relative level?

A

dBr

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5
Q

Standard test tone used for Audio measurement?

A

1000Hz or 1KHz

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6
Q

When VSWR is equal to zero, this means?

A

No power is applied

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7
Q

_____ is the ratio of reflected voltage to the forward travelling voltage?

A

Reflection coefficient

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8
Q

Transmission lines must be matched to the load to _____

A

transfer maximum power to the load

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9
Q

Which indicates the relative energy loss in a capacitor?

A

Dissipation factor

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10
Q

What is the standard test tone?

A

0 dBm (decibel relative to milliwatt), 1mW

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11
Q

The energy that neither radiated into space nor completely transmitted.

A

Standing waves

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12
Q

Micron is equal to _____ meter.

A

10^-6

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13
Q

1 Angstrom is equal to ______ meter.

A

10^-10

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14
Q

Why is it impossible to use a waveguide at low radio frequencies?

A

Because of the size of the waveguide

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15
Q

_____ is the transmission and reception of information

A

Communications

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16
Q

What is the loss of the circuit if the power ratio of output to input is 0.01?

A

-20 (20 answer in calculator, but if input is greater than output, 1/100 = 0.01, then there is loss, formula is dBp=10log(I/O))

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17
Q

Transmission lines are either balanced or unbalanced with respect to?

A

Ground

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18
Q

The standing wave ratio is equal to _____ if the load is properly matched.

A

1

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19
Q

_____ is the advantage of the balanced transmission line compared to unbalanced transmission line.

A

Low attenuation

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20
Q

_____ is the method of determining the bandwidth of any processing system.

A

Spectral Analysis

21
Q

What causes the attenuation present in a waveguide?

A

Losses in the conducting walls of the guide

22
Q

A device that converts a balanced line to an unbalanced line of a transmission line.

A

Balun (Balancing Unit / Balanced to Unbalanced)

23
Q

What is the approximate impedance of a parallel-strip line spaced 1cm apart with the length of 50cm?

A

10 Ohms (length/spacing?)

24
Q

What is the average power rating of RG-58 C/u?

A

50W

25
Q

A coaxial cable used for high temperatures.

A

RG-211

26
Q

If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to give an overall gain of 60dB?

A

3 amplifiers (dB=10log(Power Input to Output ratio), (20dB = 10log(100))

27
Q

The Velocity factor of the transmission lines depends on _____

A

the dielectric constant of the material used.

28
Q

Impedance inversion can be obtained by?

A

A quarter wave line (a half wave, pi/2, will lead to same impedance, admittance is at pi/4 )

29
Q

Transmission lines when connected to the antennas have ______.

A

Resistive load at the resonant frequency.

30
Q

One of the following is not a bounded media: Coaxial, Two-Wire line, Waveguide, and Ocean.

A

Ocean

31
Q

The impedance measured at the input of the transmission line when its length is infinite.

A

Characteristic Impedance (the question is referring to the impedance seen at z=positive infinity, aka at the right most side, aka at the load)

32
Q

The following are considered primary line constants except ______. Conductance, Resistance, Capacitance, Complex Propagation Constant.

A

Complex Propagation Constant

33
Q

The dielectric constants of materials commonly used in transmission lines range from about?

A

1.2 to 2.8

34
Q

Typically, the velocity factor of the materials used in transmission lines range from?

A

0.6 to 0.9

35
Q

For an air dielectric two-wire line, the minimum characteristic impedance value is?

A

85 Ohms

36
Q

When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, it’s input impedance is?

A

Equivalent to parallel resonant LC circuit (Current Max, Impedance Minimum, Voltage Minimum)

37
Q

When a half-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, it’s input impedance is?

A

Equivalent to series resonant LC circuit (Current Min, Voltage Max, Impedance Max)

38
Q

The concept used to make one Smith Chart universal is called?

A

Normalization

39
Q

What are the basic elements of communications system?

A

Transmitter, Receiver and Transmission Channel

40
Q

_____ is a continuous tone generated by the combination of two frequencies of 350Hz and 440Hz used in telephone sets.

A

Call waiting tone

41
Q

_____ is the transmission of printed material over telephone lines.

A

Facsimile

42
Q

_____ are unidirectional amplifiers having 20-25 dB gain that are placed about 75km apart used to compensate for losses along the telephone line.

A

VF (Voice Frequency) Repeaters

43
Q

_____ is a component in the telephone set that has the primary function of interfacing the handset to the local loop.

A

Induction Coil

44
Q

Pulse Dialing has _____ rate

A

10 pulse per sec

45
Q

______ is a telephone wire that connects two central offices.

A

Trunk line

46
Q

The central switching office coordinating element for all cell sites that has a cellular processor and a cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities.

A

Mobile Telephone Switching Office (MTSO)

47
Q

_____ in a cellular system performs radio-related functions for cellular site.

A

Base Station

48
Q

A technology used to increase the capacity of a mobile phone system.

A

Frequency re-use

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