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 Front Back what reason for modulation involves modulating low frequency signals for transmission over long distances? Ease of Radiation What are the three general catergories used to produce modulation in radion frequency (RF) transmission today? Amplitdue, frequency, and phase When the modulating signal and carrier signal are combined within a modulator, the output signal contains a/ an carrier, upper sideband, and lower sideband If a carrier frequency of 1 MHz and a modulating tone of 10 kHz goes to the modulator the output signal include 1.01 MHz, 1 MHz, and 0.99 MHz If the modulating audio signal is 10 kHz wide, what is the bandwidth of the transmitted amplitude modulated signal? 20 kHz The bandwidth of an amplitude modulated signal is two times the modulating signal. The amount of effect or change that the intelligence has on the carrier in an amplitude modulated signal is expressed as the percent of modulation. Which statement concerning bandwidth is true? Overmodulating increases bandwidth due to the production of harmonics Reducing modulation to less than 100 percent gives no reduction in carrier power In frequency modulation (FM), the amount of oscillator frequency change is directly proportional to the amplitude of the modulating signal In frequency modulation (FM), what is considered a significant sideband? Sidebands containing at least 1 percent of the total transmitted power. What is the formula to find the modulating index? Deviation divided by frequency of the modulation. In phase modulation (PM), the carrier's phase is shifted at the rate of the modulating signal. What is the advantage of adding more phase shifts? Higher data rates with in a given bandwidth. What is the first step in the pulse code modulation (PCM) process? The analog signal is band-limited. What part of the pulse code modulation (PCM) process converts a continuous time signal into a discrete time signal? Sampling A type of pulse modulation (PM) that changes the amplitude of the pulse train to vary according to the amplitude of the input signal is called. pulse amplitude modulation If an error should occur, what data transmission is lost in a synchronous transmission? Block of data. When using vertical redundancy check (VRX), what significance does the amount of ones have in a data bit pattern? Determines parity. What two error detection methods, when used together, are 98 percent effective in detecting errors? Vertical redundancy check and longitudinal redundancy check. What error detection method adds stacked characters, divides it by 255, and disregards the answer except for the remainder? Checksum What error-correction techniques sends a retransmittal  request by the receiver to the sender if it finds an error in a received frame? Automatic retransmit on request. When using forward error control as a method of error correction, where does error correction take place? Receiving end. What does an optical source do? Converts electrical energy into optical energy. Light sources that are applicable to fiber optic waverguide are light-emitting diodes (LED) and semiconductor laser diodes. What type of light is emitted from a laser? Coherent Laser diode power coupling is measured in which range milliwatt. A device that accepts optical signals from an optical fiber and coverts them into electrical signals is called an optical receiver. Small current that flows from a photodiode even with no light is called dark current. The responsivity of a photo detector is dependent on the wavelength of light. What are the two main types of photodetectors? Positive intrinsic negative and avalanche photodiode. What photo detector converts one photon to one electron? Positive intrinsic negative (PIN) diode. What is used to extend the distance of a fiber optic communication systems link? Repeater. Which repeater amplifies optical signal without converting to and from the electrical domain? Optical amplifiers. Short sections of single fiber cables that has a connector at each end is called a patch cord. Which fiber-optic connector uses quick release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected? Straight tip (ST) Which fiber optic connector uses a push-pull engagement for mating? Subscriber (SC) What initial nuclear radiation elements generate electromagnetic pulses? Gamma rays and neutrons. High-altitude electromagnetic pulse is what type of frequency phenomenon, and involves which frequency range? Wideband; 1 hertz to 1 gigahertz A system-generated electromagnetic pulse is a problem for  satellites and reentry vehicles that are directly exposed to nuclear radiations from a high-altitude burst. Which distinct region of the source region electromagnetic pulse is produced by the interactions between the weapon products and the earth's atmosphere? Source What electromagnetic pulse region is the principal threat to electronic systems by cable? Radiated. How does scintillation effects communications? Transmitted signal fading caused by multiple path propagation through the structured plasma field. Atmospheric disturbances from initial nuclear radiation on higher frequencies affect communications by which types of effects? Scintillation Which one of the following statements are true concerning shielding? Sensitive equipment will be located within the shielded barrier. What is the purpose of bonding? To ensure a mechanically strong, low impedance interconnection between metal objects. Which types of filters are always used in combination with surge arresters? Linear If the interference can be eliminated by disconnecting the receiving antenna, the source of the disturbance is most likely external to the radio. What is an example of intentionally induced electromagnetic interference (EMI)? Jamming What type of electromagnetic interference (EMI) occurs when a receiver responds to off-frequency signals? Spurious responses What type of equipment often generates many spurious emissions? Rapid tuning transmitter. What man-made noise results from voltage surges, arcing, or corona discharges? Power line. How can you normally eliminate electromagnetic interference (EMI) noise bursts caused by sodium and mercury vapor  lights that have stopped working while the power  is still applied? Change the bulb. What Air Force program is used to resolve an electromagnetic interference (EMI) incident? Spectrum interference resolution (SIR) At what level does the Air Force want electromagnetic interference (EMI) problems resolved? Affected unit. What is the first step in the Air Force spectrum interference resolution (SIR) program? Identify the source. What do you do when you are reasonably sure electromagnetic interference (EMI) exists? Systematically gather data for analysis. Who is initially responsible for reporting an electromagnetic interference (EMI)? The operator. Which Air Force service provides on-site direction finding and interference problem analysis? Quick Fix Interference Reduction Capability. What program addresses persistent and recurring interferences problems in joint operations? Joint Spectrum Interference Resolution (SIR) Who is tasked to provide interference resolution support to the unified commanders? Joint Spectrum Center (JSC) 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? Touch-hold push button. Which current range on the Fluke 8025A do you selct to measure 250 milliamps alternating current (AC)? Milliamps/amp AC When testing a diode with the 8025A, the leads across a "good" diode produces an "OL" (open) on the display in one direction while reversing the leads produces a continuous audible tone. How are voltage, time , and depth represented on the oscilloscope display? Voltage = vertical axis, time = horizontal axis, and depth = intensity. Which mode of triggering an oscilloscope causes a trace to be drawn on the screen at all times, whether there is an input signal or not? Auto Which probe does not need to actually make contact with the circuit under test? Current probe What digital storage oscilloscope circuit compensates for high sampling rates of high frequency signals? Charged coupled device. Sampled data points are stored in the memory of a digital storage oscilloscope as waveform points What area of a digital storage oscilloscope takes digitized samples and performs numerous manipulations on the data including measuring rise and fall time, periods, time intervals, and math computations? Microprocessors. What type of sampling does a digital storage oscilloscope normally use on single-shot or seldom-occurring signals? Real-time In real-time sampling, what type of interpolation is used when measuring pulse waves? Linear Which are the three types of digital storage oscilloscope acquisition modes, and which is the standard operating mode? Sample, peak detect, averaging; sample In acquiring a 4K record length on a digital storage oscilloscope, how many samples can you view at one time? 1,000 What test equipment provides a bit error detection system that can determine the received data quality after traveling over a communications link? Bit error rate (BER) 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 What pattern simulator section of the bit error rate test set converts the non-return zero-level (NRZ-L) data into the desired coding, such as non-return zero-mark (NRZ-M)? Code converter. What pattern synchronizer and error counter section of the bit error rate test set internally generates its own pattern to compare with the received data from the data/clock receivers? Pseudo random noise (PRN) synchronizer/ comparator. Which of these bit rates do you use for a bit error rate test on a 64 Kbps data circuit? 64 Kbps On the bit error rate test (BER) set, the 25-pin connectors are designed to operate with the data modems to simplify connection of test equipment to the modem under test and to carry the necessary signaling and handshake signals for modem operations. System grounds must continually be tested? periodically A known current is generated by the earth ground tester between the earth ground electrode and the auxiliary current probe Where is voltage potential measured in the fall of potential ground testing method? Between the auxiliary potential electrode and the earth ground electrode. The Institute of Electrical and Electronics Engineers (IEEE) have recommended a ground resistance value of 5 ohms or less What components on a protocol analyzer process the frames based on the selected test and user configuration inputs? Central processing unit (CPU) What protocol analyzer teat window provides information concerning the network utilization and frame error that are related to a specific protocol? Protocol statistics What protocol analyzer test window reports errors that occur at the physical layer such as bad frame check sequence (FSC), short frames, and jabbers? Media access control (MAC) node statistics. What active test is selected to see the path that the packets are traveling and the time it takes the packets to compete the trip. Trace Route. Which one of these is not an application of a radio frequency (RF) generator? Verifying transmitter frequencies. A power reading that uses the abbreviation dBm indicates the ratio of decibels relative to a 1-milliwatt standard During what operation is the radio frequency blanking output used on the HP 436A power meter? During the automatic zeroing operation Plug-in elements of the wattmeter are selected based on the frequency and power to be measured. The two switches on the front panel of the wattmeter is to correspond to the power range of the forward element. When reading forward power on a wattmeter, what does two right facing arrow head mean ? Power exceeds 120 percent of the range. What feature is useful for making adjustments to optimize any of the parameters which the wattmeter measures? peaking aid Which measurements are not made with a spectrum analyzer? peak-peak voltage. Which are the correct four classes of electronic counters? Frequency counters, universal counters, microwave counters, and reciprocals counters.  (FUMR) What test equipment combines the operations of many test instruments into a single compact unit? Communication service monitor What function is not part of the communication service monitor? Analog multimeter What operational capability of the communication service monitor produces sine, square , and triangle waveforms? Function generator
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