Flashcards
Flashcards 2
Cards in this deck (100)
- 1What happens when radio waves strike an object?Some of the energy is reflected.
- 2Approximately how long does it take for radio frequency energy to travel 1 nautical mile to a target and return to the radar?12.36 μs.
- 3What radar subassembly allows the radar system to transmit and receive from the same antenna?Duplexer
- 4Which major component of a radar system sends and receives radio frequency signals from the atmosphere?Antenna.
- 5Which feedhorn is used only for receiving?Passive.
- 6One use for the beam-lobing switch of the multi-feedhorn system is toroute the received signal from the number one feedhorn to a dummy load.
- 7We sometimes use the term stacked-beam radar to refer to contiguousbeams stacked in elevation.
- 8What do we call the fictitious surface on or near an antenna?Antenna aperture.
- 9The shape of the beam of radar energy and its antenna pattern depend on the radar’spurpose.
- 10What precision scan radar system uses continuous rotation of a pencil beam (narrow angle in both dimensions) around the aircraft and uses the phase of the return signal modulation to maintain track in both azimuth and elevation?Conical.
- 11What scan system uses a thin beam to cover a rectangular area by sweeping the area horizontally with the angle of elevation incrementally stepped up or down with each horizontal sweep of the sector?Raster.
- 12Which scan radar is also used in the acquisition phase by some airborne intercept radars?Raster.
- 13What is the name of radio frequency waves bent upwards, instead of toward, the earth?Subrefraction.
- 14What causes delayed, but separate, pulses?Near-simultaneous reception of pulse-type information.
- 15Attempts to reduce multipath effects on radar tracking accuracy include the use offrequency agility.
- 16What method of modulation does an A-scan indicator use to display video?Deflection.
- 17What type of radar system uses a B-scan indicator?Precision approach.
- 18What target information is provided by a plan-position indicator?Range and azimuth.
- 19In a Raster scan indicator, how many vertical scan periods does it take to produce one complete picture?2.
- 20Which indicator component produces signals that determine the overall operation of what the indicator will do?Data processing circuits.
- 21Which indicator component’s main purpose is to control the intensity of the cathode-ray tube (CRT) electron beam?Video circuits.
- 22In a typical indicator system, where is digital display data from the data processing circuits converted into analog drive signals?Deflection circuits.
- 23Refer to figure 2–9. What is the leading edge-to-leading edge spacing between P1 and P3 of Mode 3?8 μsec.
- 24An X pulse is present in an selective identification feature (SIF) code train whenthe aircraft is a pilotless drone or missile.
- 25Which selective identification feature special response explains a 7500 reply?Hijacking.
- 26What possible input voltage(s) may be supplied to the AN/UPM–155 Radar Test Set for operation?115 Vac or 230 Vac.
- 27What factor determines the spacing of the sidebands in an amplitude modulated signal?Frequency of the modulating signal.
- 28In frequency modulation, the amount of oscillator frequency change isdirectly proportional to the amplitude of the modulating signal.
- 29In phase modulation, the carrier’sphase shifts at the rate of the modulating signal.
- 30What is the first step in the pulse code modulation process?The analog signal is band-limited
- 31How does synchronous transmission reduce the overhead costs of data transmission?Blocks many characters together for transmission.
- 32Using the longitudinal redundancy check method of error correction, what does the receiver compare with the transmitter to ensure the transmission of data is accurate?Block check character.
- 33When used together, what two error detection methods are 98 percent effective in detecting errors?Vertical redundancy check and longitudinal redundancy check.
- 34What error detection method is used for checking a data block greater than 512 and is about 99 percent effective in most applications?Cyclic redundancy.
- 35What is the most common error correction technique in electronic transmissions or circuits?Automatic retransmit on request.
- 36When using forward error control as a method of error correction, where does error correction take place?Receiving end.
- 37Which statement describes an advantage of using fiber optic cable?Electromagnetic fields do not affect fiber optic cables.
- 38What component of a fiber optic cable is the optical transmission path?Core.
- 39What component of a fiber optic cable provides the reflective surface that allows light to propagate?Cladding.
- 40What type of buffer allows the fiber optic cable to be twisted or pulled with little stress on the fiber?Loose tube.
- 41When considering light wave propagation, what is the name of the angle between the normal in the first material and the ray that is bounced back in the first material?Angle of reflection.
- 42What is the principle on which fiber optics work?Total internal reflection.
- 43What logarithmic expression do we use to specify the ratio of power loss in fiber optic cables?dB/km.
- 44What occurs because of imperfections in an optical fiber’s basic structure?Scattering.
- 45What is the most useful way to classify fiber optic cable?Core’s refractive index profile and number of modes.
- 46What type of fiber is the least efficient, with the highest dispersion and has a core diameter range of 30μm to over 800μm?Multimode step-index.
- 47What type of fiber has a core diameter of 50–125 micrometers (um) and consists of numerous concentric layers of glass, something like the annular rings of a tree configured to reduce dispersion?Multimode graded-index.
- 48Which feature of the Fluke 8025A multimeter do you use to select various measurement functions?Rotary switch.
- 49Which feature of the Fluke 8025A locks the measurement into the display for viewing and automatically updates the display when you take a new measurement?Touch-hold push button.
- 50When you make a resistance measurement, how do you electrically isolate a resistor from the circuit?Desolder one side of the resistor.
- 51Which Fluke 8025A multimeter function displays “OL” (open) with the leads connected in one direction while reversing them produces a continuous audible tone?Diode test.
- 52What is caused by low-insulation resistance between conductors?High-attenuation, crosstalk, and noise.
- 53Insulation resistance increases as thethickness of the insulating material increases.
- 54When using the AN/PSM–2 megger, you apply the correct regulated output voltage by turning the hand-crankat a rate to keep the indicator lights at a steady glow.
- 55How many volt megohmmeter do you use on paper insulated conductor cable?500.
- 56You must discharge conductors after insulation resistance measurements toprevent shock.
- 57What is the earth ground standard for communications facilities?10 ohms or less.
- 58How are voltage, time, and depth represented on the oscilloscope display?Voltage = vertical axis, time = horizontal axis, and depth = intensity.
- 59Which input coupling switch position allows you to view both alternating current (AC) and direct current (DC) components of the input signal?DC.
- 60Which oscilloscope probe is essentially just a shielded piece of wire?Passive 1:1 probe.
- 61Which probe lets you use the oscilloscope to measure higher voltage levels, raises the input impedance, and attenuates noise?Passive divider, 10:1 probe.
- 62Which probe does not need to actually make contact with the circuit under test?Current probe.
- 63Sampled data points are stored in the memory of a digital storage oscilloscope aswaveform points.
- 64What area of a digital storage oscilloscope takes digitized samples and performs numerous manipulations on the data including measuring rise and fall times, periods, time intervals, and math computations?Microprocessors.
- 65What type of sampling does a digital storage oscilloscope normally use on single-shot or seldom-occurring signals?Real-time.
- 66What type of interpolation does a digital storage oscilloscope use to measure pulse waves?Linear.
- 67What is the primary use of a signal generator?Align frequency sensitive or tuned circuits.
- 68What is the frequency range of an audio signal generator?20 Hz to 20 kHz.
- 69Which one of these is not an application of a radio frequency generator?Aligning galvanometers.
- 70How is a radio frequency generator used?align telemetry receivers.
- 71The 10:1 power ratio represented by 1 bel can also be represented by how many decibels (dB)?10 dB
- 72What does a power reading that uses the abbreviation dBm indicate?Ratio of decibels relative to a 1-milliwatt standard.
- 73If someone says, “we doubled our transmitter power;” how much is the gain in dB?3 dB.
- 74The measurable frequency and power ranges of the HP 436A power meter system are determined by theselected sensor.
- 75Which measurement is not made with a spectrum analyzer?Peak-peak voltage
- 76Which measurement do you make with a spectrum analyzer?Subcarrier oscillator outputs
- 77Which electronic counter measurement represents the average bit-to-bit time of an input signal?Period.
- 78Which electronic counter measurement counts the number of bits in a pulse train?Totalize.
- 79Which are the correct four classes of electronic counters?Frequency, universal, microwave, and reciprocal.
- 80A dummy load is constructed so that radio frequency (RF) power isabsorbed
- 81What piece of test equipment provides the ideal method for isolating waveguide arcing?Dummy load.
- 82When marking cables, what is the distance between the “TO” and “FROM” markers?2 inches.
- 83In telecommunications cable, the “tip” or “primary” color group order iswhite, red, black, yellow, and violet.
- 84What is the “ring” or “secondary” color code for telecommunications cable?Blue, orange, green, brown, and slate.
- 85What standard do most newly installed network cables follow?T568B.
- 86What are the three main functions of grounding?Personnel safety, equipment protection, and noise reduction.
- 87What establishes a low-impedance path between two metal surfaces?Bonding.
- 88Bonds in the earth electrode subsystem normally are direct permanent bonds and do not exceed a resistance of1 milliohm.
- 89What kinds of bonds are normally applied to signal reference bonds?Mechanical.
- 90What are the two basic functions of shielding?Prevent interference between multiple emanating systems and minimize compromising
emanations. - 91Equipment should be designated as RED when processingclear-text classified information.
- 92Which one of these is considered a primary cell?Carbon zinc.
- 93What power line fault category is symptomatic of a short term decrease in voltage levels?Sag.
- 94What power line fault category is symptomatic of a total loss of utility power?Blackout.
- 95What power line fault category is symptomatic of an instantaneous or dramatic increase in voltage?Spike.
- 96What power line fault category is more typically referred to as electro-magnetic interference and radio frequency interference?Noise.
- 97What type of uninterruptible power supply (UPS) has traditionally referred to as “offline” by technicians?Passive standby.
- 98What type of uninterruptible power supply (UPS) offers the highest level of protection?Double conversion.
- 99How many phases of generator power are usually required for industrial and commercial applications?Three-phase.
- 100What part of the power generation process allows a smooth transition of electrical current between multiple sources and the load?Automatic Transfer Switch.
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- Flashcards on Flashcards 2, created by Oschelle Torres on 14/02/2017.
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