ATT Test 13 (Latest 2024/ 2025 Update) Questions and Verified Answers| 100% Correct| Grade A
ATT Test 13 (Latest 2024/ 2025 Update)
Questions and Verified Answers| 100%
Correct| Grade A
Q: What does Phase Lock Loop do?
Answer:
Compares output of VCO with a reference frequency
Q: What happens if the output of VCO is different than the reference frequency?
Answer:
DC controlling voltage is generated to steer VCO to correct output
Q: What frequency range do AM broadcasts use?
Answer:
535-1605 kHz
Q: What are two types of AM receiver tuning?
Answer:
Synthesized and manual
Q: What are two types of synthesized tuning?
Answer:
Direct and indirect synthesis
Q: What are 4 components of PLL?
Answer:
Phase detector, loop filter, VCO, and frequency counter/divider
Q: What are 3 benefits of synthesized tuning?
Answer:
Greater freq stability, freq changed electronically, reduced cost, smaller size
Q: What type of tuning incorporates PLL and VCO to provide desired frequency?
Answer:
Indirect synthesis
Q: What type of tuning uses filtering, mixing, multiplication to provide specific frequency?
Answer:
Direct synthesis
Q: What is purpose of RF section?
Answer:
Eliminate all frequencies except tuned RF
Q: What is a significant advantage of SSB?
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What is amplitude modulation? Information is encoded into carrier wave by varying RF carriers amplitude and maintaining constant frequency
AM IF signal is at what frequency? 455 kHz
FM IF signal is at what frequency? 10 MHz
When the carrier is modulated, where is the information located? Upper and lower sidebands of composite signal
What is the difference frequency known as? Intermediate Frequency
What is the receivers ability to faithfully reproduce a desired signal is based on what two things? Its sensitivity and selectivity
What does Phase Lock Loop do? Compares output of VCO with a reference frequency
What happens if the output of VCO is different than the reference frequency? DC controlling voltage is generated to steer VCO to correct output
What frequency range do AM broadcasts use? 535-1605 kHz
What are two types of AM receiver tuning? Synthesized and manual
What are two types of synthesized tuning? Direct and indirect synthesis
What are 4 components of PLL? Phase detector, loop filter, VCO, and frequency counter/divider
What are 3 benefits of synthesized tuning? Greater freq stability, freq changed electronically, reduced cost, smaller size
What type of tuning incorporates PLL and VCO to provide desired frequency? Indirect synthesis
What type of tuning uses filtering, mixing, multiplication to provide specific frequency? Direct synthesis
What is purpose of RF section? Eliminate all frequencies except tuned RF
What is a significant advantage of SSB? Efficient use of RF spectrum
SSB transmissions limit the effects of what? Selective feeding
What are 5 types of SSB? Pilot carrier, vestigial sideband, lincompex, ISB, Standard SSB
What type of SSB is used by the military? ISB
What type of SSB is used by amateur radio operators? Standard SSB
What type of SSB is used by TV video transmissions and conserves bandwidth? Vestigial
What type of SSB has two sidebands that can each carry completely different intelligence? ISB
What is the purpose of balanced modulator? Eliminates/suppresses carrier
What is the heart of sideband generation? Balanced modulator
What are 3 methods for SSB generation? Filter method, phase method, Third/Weaver method
What is a unique aspect of SSB? Must recreate carrier in order for intel to be detected
What frequency range is used by CB? 26.965-27.405 MHz
What is heterodyning? Combining 2 frequencies to convert to new frequency without altering intel in original
SSB is not _ dependent Phase What are two types of AGC? Carrier and Audio derived What is the bandwidth of HF? 3MHz to 30MHz What is the purpose of the HF system? Allows long range high frequency surface to surface, surface to air, air to air, air to surface, two way comms and data comms at LOS and over horizon What are 4 modes of operation of HF system? AM, AME, USB, LSB What is the most common HF mode of operation? USB What type of HF causes large bandwidth and large power consumption? AM What type of HF has the carrier reinserted prior to transmission? AME What type of HF removes both LSB and carrier and is more efficient than AM with smaller bandwidth? USB What type of HF is modulated by a 1kHz tone and whose transmit frequency is 1 kHz lower than carrier? LSB What types of HF only output power when mic is keyed and user talks? USB and LSB What are 5 components of HF system? Receiver transmitter, antenna, antenna coupler, control head, and audio system Which part of HF system creates sidetone that is sent to audio system? Receiver transmitter What component is used to electrically change length of antenna to allow large bandwidths of frequency to use antenna? Antenna coupler (couples HF system to antenna) The antenna coupler is also used to perform which two functions? Match impedance and monitor SWR Which part of HF system rough tunes coupler? Receiver transmitter FM guard bands are kHz at upper and lower boundary of each channel and guard against interference 24kHz
What are two types of FM generation? Direct (capacitor) and indirect (phase modulation)
What are the primary advantages of FM? Greater noise suppression, high fidelity (stereo) reception, less interference (limits capture effect), reduced transmitter power to cover assigned area
What are two types of phase detectors? Sequential (digital) and Multiplier (no memory)
What is the a general rule of thumb regarding the sun and frequency? The higher the sun the higher the frequency
FM has a carrier and a number of sidebands Infinite
FM sidebands have amplitudes and are always an __ distance from center (carrier) frequency equal amplitude, equal distance from carrier
What is the bandwidth of narrow band FM? 10 to 30 kHz
Why is NBFM reduced bandwidth? To accommodate signal/voice transmissions
What is primary advantage of NBFM? RF spectrum conservation
What are four steps of TS NBFM? Assess, troubleshoot, repair, re-assess
What frequency are NBFM guard bands? Two 5kHz guard bands
Shorts usually also cause what? Opens
What are diodes susceptible to? Heat