Volume 1 URE

Question 1

What are the three general categories used to produce modulation in radio frequency (RF) transmission today?

Answer 1

Amplitude, frequency, phase

Question 2

When the modulating signal and carrier signal are combined within a modulator, the output signal contains ______.

Answer 2

carrier, upper sideband, and lower sideband

Question 3

If a carrier frequency of 1 MHz and a modulating tone of 10 kHz goes to the modulator, the output signal includes ________.

Answer 3

1.01 MHz, 1 MHz, and .99 MHz

Question 4

The bandwidth of an amplitude modulated signal is _________.

Answer 4

two times the modulating signal

Question 5

If an oscilloscope displays a modulation envelope having an Emax of 200 volts and an Emin of 20 volts, what is the modulation percentage?

Answer 5

%mod = Emax-Emin/Emax+Emin • 100
%mod = 200-20/200+20
%mod = 180/220
%mod = 81.8

Question 6

Which statement concerning bandwidth is true?

• Overmodulating increases bandwidth because the distortion produces harmonics
• Undermodulating increases bandwidth because the distortion produces harmonics
• Overmodulating increases bandwidth because the output’s amplitude is increased
• Undermodulating increases bandwidth because the output’s amplitude is decreased

Answer 6

Overmodulation increases bandwidth because the distortion produces harmonics.

Question 7

The output of an oscillator in a frequency modulation (FM) modulator increases in frequency with each __________.

Answer 7

positive half cycle of the modulating signal

Question 8

In frequency modulation, a significant sideband contains at least what percentage of the total transmitted power?

Answer 8

1%

Question 9

What is the formula to find the modulating index?

Answer 9

Deviation divided by the frequency of modulating signal.

Question 10

A 5 kHz modulating signal has enough peak voltage to cause a deviation of 15 kHz. What is the modulation index?

Answer 10

MI = Deviation/Modulating signal frequency

MI = 15/5

MI = 3

Question 11

What is the name given to the narrow frequency band between adjacent stations which prevents frequency modulated sidebands from overlapping?

Answer 11

Guard band

Question 12

In phase modulation, what part of the carrier signal is varied?

Answer 12

Phase

Question 13

In phase modulation, the carrier’s __________.

Answer 13

phase is shifted at the rate of the modulating signal

Question 14

What is the first step in the pulse code modulation process?

Answer 14

The analog signal is band limited.

Question 15

What part of the pulse code modulation process converts a continuous time signal into a discrete time signal?

Answer 15

Sampling

Question 16

In asynchronous transmissions, what bit is used by the receiving device to verify that the transmission was received correctly?

Answer 16

The parity bit

Question 17

If an error should occur, what transmission is lost in a synchronous transmission?

Answer 17

An entire block of data

Question 18

When using vertical redundancy check, what significance does the amount of ones have in a data bit pattern?

Answer 18

It determines parity

Question 19

What error detection method is used for checking a data block greater than 512 and is about 99% effective in most applications?

Answer 19

Cyclic redundancy check

Question 20

When using forward error control as a method of error correction, where does error correction take place?

Answer 20

Receiving end

Question 21

Light sources that are applicable to fiber optic waveguides are light-emitting diodes and ________.

Answer 21

semiconductor laser diodes

Question 22

What type of light is emitted from a laser?

Answer 22

Coherent

Question 23

What are the two main types of photodetectors?

Answer 23

Positive intrinsic negative and avalanche photodiode

Question 24

What photodetector converts one photon to one electron?

Answer 24

Positive intrinsic negative diode

Question 25

Which repeater amplifies optical signal without converting to and from the electrical domain?

Answer 25

Optical amplifiers

Question 26

A short section of single fiber cable that has a connector at each end is called a ________.

Answer 26

patch cord

Question 27

Which fiber optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected?

Answer 27

Straight tip (ST)

Question 28

High altitude electromagnetic pulse is a wideband phenomenon that involves which frequency range?

Answer 28

1 Hz to 1GHz

Question 29

High-altitude electromagnetic pulse environment protection is important for critical, time urgent mission systems because __________.

Answer 29

High altitude EMP is the only nuclear environment that may be imposed on many systems simultaneously with the expenditure of very few weapons.

Question 30

A system-generated EMP is a problem for satellites and reentry vehicles that are _________.

Answer 30

directly exposed to nuclear radiation from high-altitude bursts

Question 31

Which distinct region of the source region electromagnetic pulse is produced by the interactions between the weapon products and the earth's atmosphere?

Answer 31

Source

Question 32

Atmospheric disturbances from initial nuclear radiation on higher frequencies affect communications with ________.

Answer 32

scintillation effects

Question 33

Currents and voltages induced on power lines, cable links, and pipelines by EMP are called _________.

Answer 33

long-line effects

Question 34

Which type of filters are always used in combination with surge arrestors?

Answer 34

Linear

Question 35

If the interference can be eliminated by disconnecting the receiving antenna, the source of the disturbance is most likely ___________.

Answer 35

external to the radio

Question 36

Little or no variation in the strength of the interfering signal when moving the antenna for short distances normally indicates _____________.

Answer 36

enemy jamming

Question 37

What type of electromagnetic interference occurs when a receiver responds to off-frequency signals?

Answer 37

Spurious responses

Question 38

Which type of intermodulation interference varies with temperature and weather conditions?

Answer 38

Rusty bolt

Question 39

What man-made noise results from voltage surges, arcing, or corona discharges?

Answer 39

Power line

Question 40

How can you normally eliminate electromagnetic interference noise bursts causes by sodium and mercury vapor lights that have stopped working while power is still applied?

Answer 40

Change the bulb

Question 41

What Air Force program is used to resolve an electromagnetic interference incident?

Answer 41

Spectrum interference resolution

Question 42

At what level does the Air Force want electromagnetic interference problems resolved?

Answer 42

Affected Unit

Question 43

What do you do when you are reasonably sure electromagnetic interference exists?

Answer 43

Systematically gather data for analysis

Question 44

Who is initially responsible for reporting electromagnetic interference?

Answer 44

The operator

Question 45

Who is tasked to provide interference resolution to the unified commanders?

Answer 45

Joint spectrum center

Question 46

Which feature of the Fluke 8025A multimeter is used to select various measurement functions?

Answer 46

Rotary switch

Question 47

Which part of the Fluke 8025A'a display section indicates the absolute value of the input?

Answer 47

Analog bar graph

Question 48

Which feature of the Fluke 8025A locks the measurement into the display for viewing and automatically updates the display when you take a new measurement?

Answer 48

The touch-hold button

Question 49

When you use the Fluke 8025A, which voltage range do you select to measure 50 volts DC?

Answer 49

Volts DC

Question 50

When testing a diode with the 8025A, the leads across a "good" diode produces an "OL" on the display in one direction while reversing the leads produces __________________.

Answer 50

A continuous audible tone

Question 51

How are voltage, time, and depth represented on the oscilloscope display?

Answer 51

Voltage on the vertical axis Time on the horizontal axis Depth as a variation if the intensity

Question 52

Which oscilloscope's input coupling position allows one to view both AC and DC components of the input signal?

Answer 52

DC

Question 53

Which oscilloscope probe is essentially just a shielded piece of wire?

Answer 53

Passive 1:1

Question 54

Which probe lets you use the oscilloscope to measure higher voltage levels, raises the input impedance, does not require a bias voltage, and attenuates noise?

Answer 54

Passive divider, 10:1

Question 55

Which probe does not need to actually make contact with the circuit under test?

Answer 55

Current

Question 56

Sampled data points are stored in the memory of a digital storage oscilloscope as ______________.

Answer 56

waveform points

Question 57

What area of a digital storage oscilloscope takes digitized samples and performs numerous manipulations on the data including measuring the rise and fall times, periods, time intervals, and math computations?

Answer 57

Microprocessors

Question 58

What type of sampling does a digital storage oscilloscope normally use on single-shot or seldom-occurring signals?

Answer 58

Real-time

Question 59

In real-time sampling, what type of interpolation is used when measuring pulse waves?

Answer 59

Linear

Question 60

In acquiring a 4K record length on a digital storage oscilloscope, how many samples can you view at one time?

Answer 60

1000

Question 61

What pattern simulator section of the bit error rate test set accepts a 48-bit parallel word and generates a serial pattern? - 48 bit transmitter only - 48 bit register and 8-bit word display - Psuedo random noise generator - Psuedo random noise comparator

Answer 61

48-bit transmitter only

Question 62

Which pattern simulator section of a bit error rate test set controls the clock selector and selects either the external clock or the internal clock for processing?

Answer 62

Data/clock select encoder

Question 63

Which is the primary means of measuring the quality of transmitted digital information, and how is this means derived?

Answer 63

* Bit error rate (BER) | * BER is derived from the ratio of the number of bits in error to the total bits transmitted

Question 64

Which bit rate is used for a bit error rate test on a 64 kbps data circuit?

Answer 64

64 kbps

Question 65

On the bit error rate test set, the 25-pin connectors are designed to operate with data modems to _____________.

Answer 65

simplify connection of test equipment to the modem under test and to carry the necessary signaling and handshake signals for modem operations

Question 66

How often must system grounds be tested?

Answer 66

Periodically

Question 67

What type of equipment helps resolve intermittent electrical problems because of poor grounding?

Answer 67

Earth ground tester

Question 68

Resistance reading on the ground under test is plotted on a graph of _____________.

Answer 68

Resistance versus distance

Question 69

A known current is generated by the earth ground tester between the earth ground electrode and the ____________.

Answer 69

Auxiliary current probe

Question 70

What component of a protocol analyzer discards frames based on its definition or activates a trigger based on the trigger definition?

Answer 70

Filter

Question 71

What protocol analyzer test window provides information concerning the network utilization and frame error that are related to a specific protocol?

Answer 71

Protocol statistics

Question 72

What protocol analyzer test window automatically runs in the background when the protocol analyzer application is activated?

Answer 72

Node discovery

Question 73

What protocol analyzer test window provides information concerning the bandwidth utilization and number of connections that are related to specific nodes?

Answer 73

Connection statistics

Question 74

``` Which of these is not an application of a radio frequency generator? • Verifying transmitter frequency • Troubleshooting receivers • Checking antenna systems • Aligning galvanometers ```

Answer 74

Aligning galvanometers

Question 75

A power reading that uses the abbreviation dBm indicates the _____________.

Answer 75

ratio of decibels relative to a 1-milliwatt standard

Question 76

The measurable frequency and power ranges of the HP 436A power meter are determined by the ___________.

Answer 76

power sensor

Question 77

During what operation is the radio frequency blanking output used on the HP 436A power meter?

Answer 77

During the automatic zeroing operation

Question 78

The two switches on the front panel of the wattmeter correspond to the _____________.

Answer 78

power range of the forward element

Question 79

What feature is useful for making adjustments to optimize any of the parameters which the wattmeter produces?

Answer 79

Peaking aid

Question 80

Which measurement is not made with a spectrum analyzer? * Frequency stability * Peak-peak voltage * Amplitude modulation * Subcarrier oscillator outputs

Answer 80

Peak-peak voltage

Question 81

Which electronic counter measurement represents the average bit-to-bit time of an input signal?

Answer 81

Period

Question 82

What are the four classes of electronic counters?

Answer 82

* Frequency counters * Universal counters * Microwave counters * Reciprocal counters

Question 83

What function is not part of the communication service monitor? * Radio frequency generator * Analog multimeter * Oscilloscope * Receiver

Answer 83

Analog multimeter

Question 84

What is one reason for modulation of low frequency signals for transmission over long distances?

Answer 84

Ease of radiation

Question 84

What operational capability of the communication service monitor receives amplitude and frequency modulated signals?

Answer 84

Receiver

Question 86

What operational capability of the communication service monitor produces sine, square, and triangle waveforms?

Answer 86

Function generator

Question 87

Why should the number of splices be controlled during fiber optic installation?

Answer 87

To minimize transmission loss

Question 88

What is a function of Air Force Communications Special Instructions?

Answer 88

Issuance of optional equipment modifications

Question 89

What are the three main functions of grounding?

Answer 89

* Personnel safety * Equipment protection * Noise reduction

Question 90

What facility ground subsystem uses surge arrestors?

Answer 90

Lightning protection

Question 91

What facility ground subsystem is also called the safety ground?

Answer 91

Fault protection

Question 92

Bonds in the earth electrode subsystem normally are direct permanent bonds and do not exceed a resistance of _____________.

Answer 92

1 milliohm

Question 93

What kind of bond is a signal reference bond, usually?

Answer 93

Mechanical

Question 94

What are the two basic functions of shielding?

Answer 94

1. Prevent interference between multiple emanating systems | 2. Minimize compromising emanations

Question 95

What equipment should be designated as RED?

Answer 95

Equipment processing clear-text classified information

Question 96

``` Which of these is considered a primary cell? • Nickel cadmium • Carbon zinc • Lead-acid • Lithium ```

Answer 96

Carbon zinc

Question 97

What power line fault category is more typically referred to as Electro-Magnetic Interference and Radio Frequency Interference?

Answer 97

Noise

Question 98

What type of uninterruptible power supply (UPS) has traditionally been referred to as offline by technicians?

Answer 98

Passive standby

Question 99

How many phases of generator power are usually required for industrial and commercial applications?

Answer 99

Three