MCQ in Noise Part 1 _ ECE Board Exam - Ace Your Board Exam with PinoyBIX.pdf

MCQ in Noise Part 1 | ECE Board Exam 1. What is the non-continuous noise of irregular pulses or spikes of duration with high amplitudes? A. Wander B. Jitter C. Hits D. Singing View Answer: Answer: Option B Explanation: Jitter refers to the variation in the timing of a signal’s edge, resultin...

MCQ in Noise Part 1 | ECE Board Exam 1. What is the non-continuous noise of irregular pulses or spikes of duration with high amplitudes? A. Wander B. Jitter C. Hits D. Singing View Answer: Answer: Option B Explanation: Jitter refers to the variation in the timing of a signal’s edge, resulting in irregularities in the signal’s periodicity. Jitter can manifest as deviations in the time intervals between signal transitions, leading to timing uncertainties. In the context of irregular pulses or spikes with high amplitudes, jitter is a common term used to describe this type of non- continuous noise. 2. What theorem sets a limit on the maximum capacity of a channel with a given noise level? A. Nyquist theorem B. Hartley law C. Shannon-Hartley theorem D. Shannon theorem View Answer: Answer: Option C Explanation: The Shannon-Hartley theorem establishes a fundamental limit on the maximum achievable data rate (capacity) of a communication channel, considering both the bandwidth of the channel and the level of noise present. The formula is given by: C = B⋅log2(1 + S/N) where: C is the channel capacity in bits per second. B is the bandwidth of the channel in hertz. S is the signal power. N is the noise power. This theorem is crucial in communication system design, providing insights into the trade-off between bandwidth and signal-to-noise ratio to maximize data transmission rates. The other options are not specifically associated with setting limits on channel capacity: 3. Quantizing noise occurs in A. PCM B. PLM C. PDM D. PAM View Answer: Answer: Option A Explanation: Quantizing noise arises in the process of converting analog signals to digital signals during Pulse Code Modulation (PCM). PCM involves discretizing the amplitude of the analog signal into a finite number of quantization levels. The quantization process introduces errors, leading to quantizing noise. The other options are not typically associated with quantizing noise: B. PLM (Pulse Length Modulation): This term is not commonly used in the context of quantization. C. PDM (Pulse Density Modulation): PDM is a form of modulation, and quantizing noise is not directly related to it. D. PAM (Pulse Amplitude Modulation): While PAM involves the modulation of signal amplitudes, the term “quantizing noise” is specifically associated with the discretization process in PCM. 4. Noise always affects the signal in a communications systems at the ________. A. transmitter B. channel C. information source D. destination View Answer: Answer: Option B Explanation: Noise in a communication system typically affects the signal while it travels through the communication channel. The channel is the medium through which the signal is transmitted, and various factors, such as interference, thermal noise, or environmental conditions, can introduce noise to the signal during its journey from the transmitter to the destination. The other options represent different stages in a communication system: A. Transmitter: This is where the signal is generated and modulated for transmission. C. Information source: This is the origin of the message or data. D. Destination: This is where the signal is received and demodulated. However, the primary stage where noise is introduced to the signal is during its passage through the communication channel. 5. _________ is the random and unpredictable electric signals from natural causes, both internal and external to the system. A. Interference B. Attenuation C. Distortion D. Noise View Answer: Answer: Option D Explanation: Noise refers to random and unpredictable electric signals that arise from various natural causes, both internal and external to a system. These signals can interfere with the intended communication or operation of an electronic system. Noise can manifest in different forms, such as thermal noise, electromagnetic interference, or crosstalk. It is a common challenge in electronic systems, and minimizing its impact is crucial for maintaining signal integrity and system performance. The other options have specific meanings in the context of electronic systems: A. Interference: Interference generally refers to the introduction of unwanted signals that disrupt the normal operation of a system. B. Attenuation: Attenuation is the decrease in signal strength as it travels through a medium, typically a transmission line or a channel. C. Distortion: Distortion involves alterations in the shape or characteristics of a signal, often leading to a loss of fidelity in the transmitted information. 6. Noise from random acoustic or electric noise that has equal energy per cycle over a specified total frequency band. A. Gaussian noise B. Whiter noise C. Thermal noise D. All of the above View Answer: Answer: Option D Explanation: The description provided—noise with equal energy per cycle over a specified total frequency band—applies to various types of noise, and the terms listed fall into that category: A. Gaussian noise: Gaussian noise is a type of random noise that has a normal distribution, and it exhibits equal energy per cycle over its frequency band. B. White noise: White noise is another term for random noise that has a flat frequency spectrum, meaning it has equal energy at all frequencies within a specified range. C. Thermal noise: Thermal noise, also known as Johnson-Nyquist noise, is random noise generated by the thermal agitation of charge carriers in a conductor. Like Gaussian and white noise, it has equal energy per cycle over its frequency band. Therefore, all the options (A, B, and C) are correct in describing noise with equal energy per cycle over a specified total frequency band. 7. Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques View Answer: Answer: Option B Explanation: Quantization in PCM (Pulse Code Modulation) involves the process of approximating the continuous amplitude of an analog signal into a finite set of discrete levels. This discretization introduces errors known as quantization noise. The more levels used in quantization, the lower the quantization noise, but it cannot be entirely eliminated due to the discrete nature of the representation. The other options are not directly associated with the generation of quantization noise: A. Serial transmission errors: These refer to errors occurring during the transmission of digital data and are unrelated to the quantization process. C. The synchronization between encoder and decoder: Synchronization is crucial for proper communication but is not the cause of quantization noise. D. Binary coding techniques: Binary coding is a method for representing information and is not the direct cause of quantization noise. Therefore, the correct answer is B, the approximation of the quantized signal. 8. A particular circuit that rids FM of noise A. Detector B. Discriminator C. Phase Shifter D. Limiter View Answer: Answer: Option D Explanation: In frequency modulation (FM), a limiter is a circuit designed to limit or clip the amplitude of the FM signal. The primary purpose of a limiter in an FM receiver is to suppress amplitude variations caused by noise. The limiting action ensures that the signal remains constant in amplitude, allowing subsequent stages of the receiver to more effectively deal with the frequency variations introduced by the FM modulation. The other options are not specifically associated with noise reduction in FM: A. Detector: In FM, the detector is responsible for recovering the audio or baseband signal from the modulated carrier, but it does not specifically address noise reduction. B. Discriminator: The discriminator is part of the FM demodulation process, focusing on extracting the audio or baseband signal, not noise reduction. C. Phase Shifter: A phase shifter is generally used to introduce a phase shift in a signal and is not directly related to noise reduction in FM. Therefore, the correct answer is D. Limiter. 9. What is the reference noise temperature in degrees Celsius? A. 17 B. 273 C. 25 D. 30 View Answer: Answer: Option A Explanation: In the field of electronics and communication systems, the standard reference noise temperature is often considered to be 290 Kelvin (approximately 17 degrees Celsius). This value is commonly used in thermal noise calculations. 10. Unwanted radio signal on assigned frequency. A. Splatter B. RFI C. Noise D. EMI View Answer: Answer: Option C Explanation: In the general context of radio communication, the term “noise” can indeed refer to unwanted signals or disturbances on a frequency. Different types of noise, such as thermal noise or atmospheric noise, can impact radio communication systems. 11. What is the reliable measurement for comparing amplifier noise characteristics? A. Thermal agitation noise B. Noise factor C. Noise margin D. Signal-to-noise View Answer: Answer: Option B Explanation: The reliable measurement for comparing amplifier noise characteristics is the noise factor. The noise factor is a parameter that quantifies how much the amplifier degrades the signal-to-noise ratio. It is a dimensionless value typically expressed in decibels (dB). A lower noise factor indicates better noise performance. The other options are related to noise but are not specifically used for comparing amplifier noise characteristics: A. Thermal agitation noise: This refers to the inherent noise due to the thermal motion of electrons in a conductor and is not a measurement for comparing amplifier noise characteristics. C. Noise margin: Noise margin is a term used in digital systems to measure the sensitivity of a device to noise, but it is not specific to amplifier comparisons. D. Signal-to-noise: While signal-to-noise ratio is essential for assessing overall system performance, noise factor is specifically tailored for comparing amplifier noise characteristics. Therefore, the correct answer is B. Noise factor. 12. _________ is measured on a circuit when it is correctly terminated but does not have any traffic. A. White noise B. Galactic noise C. Impulse noise D. Atmospheric noise View Answer: Answer: Option A Explanation: White noise is measured on a circuit when it is correctly terminated but does not have any traffic. White noise is a random signal with equal intensity at different frequencies, making it suitable for measuring the inherent noise characteristics of a system. In the absence of any specific signals or traffic, measuring white noise provides a baseline for understanding the noise floor of the system. The other options are different types of noise: B. Galactic noise: Noise from extraterrestrial sources. C. Impulse noise: Noise characterized by sudden, sharp changes in amplitude. D. Atmospheric noise: Noise caused by atmospheric disturbances and conditions. Therefore, in the context of measuring noise on a circuit with correct termination and no traffic, the term is white noise. 13. Which standard recommends crosstalk limits? A. CCIT G.152 B. CCIT G.150 C. CCIT G.151 D. CCIT G.161 View Answer: Answer: Option C Solution: 14. Which standard is utilized in intermodulation noise rates on PCM audio channels? A. CCIT Rec. G.151 B. CCIT Rec. G.172 C. CCIT Rec. G.190 D. CCIT Rec. G.190 View Answer: Answer: Option B Solution: 15. What is the reference frequency of CCIT phosphomeric noise measurement? A. 800 Hz B. 1000 Hz C. 1500 Hz D. 3400 Hz View Answer: Answer: Option A Solution: 16. Reference temperature use in noise analysis A. 75K B. 250K C. 290K D. 300K View Answer: Answer: Option C Explanation: In the context of noise analysis, particularly in electronics and communication systems, a common reference temperature is 290 Kelvin (K). This temperature is associated with the standard reference temperature used in calculating thermal noise, also known as Johnson-Nyquist noise. The formula for thermal noise power (N0) is given by: N0 = k⋅T⋅B where: k is Boltzmann’s constant (1.38 × 10^−23 J/K), T is the temperature in Kelvin, B is the bandwidth. When T is set to 290K, it represents a commonly used standard reference temperature for noise calculations in electronic systems. Therefore, the correct answer is C. 290K. 17. Which noise is produced by lighting discharges in thunderstorms? A. White noise B. Extraterrestrial noise C. Industrial noise D. Atmospheric noise View Answer: Answer: Option D Explanation: Atmospheric noise, also known as static or natural radio noise, is produced by various natural sources, including lightning discharges during thunderstorms. The electromagnetic radiation generated by lightning contributes to atmospheric noise in the radio frequency spectrum. This noise is broadband and can be characterized by random variations in amplitude and frequency. The other options are not specifically associated with noise produced by lightning discharges: A. White noise: White noise is a broad-spectrum noise with equal intensity at different frequencies and is not specifically linked to lightning discharges. B. Extraterrestrial noise: Noise from extraterrestrial sources, such as cosmic sources, but not specifically related to lightning discharges. C. Industrial noise: Noise generated by industrial activities, machinery, and equipment, but not directly related to atmospheric phenomena like thunderstorms. Therefore, in the context of noise produced by lightning discharges in thunderstorms, the correct answer is D. Atmospheric noise. 18. Man-made noise is usually from _______. A. transmission over power lines and by ground wave B. sky-wave C. space-wave D. troposphere View Answer: Answer: Option A Explanation: Man-made noise, also known as industrial or anthropogenic noise, often originates from various human activities. One common source of man-made noise is the transmission of signals over power lines, as well as ground wave propagation. Power lines can introduce unwanted electromagnetic interference into communication systems, affecting the quality of signals. The other options are associated with natural phenomena: B. Sky-wave: Relates to the propagation of radio waves in the ionosphere. C. Space-wave: Involves the direct line-of-sight transmission between antennas. D. Troposphere: Part of the Earth’s atmosphere and is not typically associated with man-made noise. Therefore, the correct answer is A. Transmission over power lines and by ground wave. 19. nif stands for A. Non-intrinsic figure B. Noise improvement factor C. Narrow intermediate frequency D. Noise interference figure View Answer: Answer: Option B Solution: 20. Industrial noise frequency is between _____. A. 0 to 10 KHz B. 160 MHz to 200 MHz C. 15 to 160 MHz D. 200 to 3000 MHz View Answer: Answer: Option C Explanation: Industrial noise frequency typically falls within the range of 15 to 160 MHz. This frequency range covers the radio frequency (RF) spectrum, and industrial noise sources, such as electronic equipment and machinery, can emit electromagnetic interference (EMI) signals within this range. It’s important to consider and mitigate such interference in communication systems and electronic devices operating in this frequency band. 21. External noise fields are measured in terms of _______. A. rms values B. dc values C. average values D. peak values View Answer: Answer: Option D Solution: 22. Form of interference caused by rain or dust storms. A. Precipitation static B. Shot-noise C. Galactic noise D. Impulse noise View Answer: Answer: Option A Explanation: Precipitation static refers to interference caused by atmospheric conditions, particularly rain or dust storms. It occurs when charged particles, such as raindrops or dust, impact antennas or other conductive surfaces, leading to the buildup of electrostatic charges. This static buildup can interfere with radio signals and cause disruptions in communication systems. The other options represent different types of noise: B. Shot-noise: Random noise associated with the discrete nature of electrical charge. C. Galactic noise: Noise from extraterrestrial sources, such as cosmic radiation. D. Impulse noise: Noise characterized by sudden, sharp changes in amplitude. Therefore, in the context of interference caused by rain or dust storms, the correct answer is A. Precipitation static. 23. At 17˚C, the noise voltage generated by 5 kΩ resistor, operating over a bandwidth of 20 KHz is A. 1.3 nV B. 1.3 µV C. 1.3 pV D. 1.3 mV View Answer: Answer: Option B Solution: Solution: The noise voltage generated by 5 kΩ resistor 24. ________ is an electric noise produced by thermal agitation of electrons in conductor and semiconductor. A. External noise B. Internal noise C. Thermal noise D. Flicker View Answer: Answer: Option C Explanation: Thermal noise, also known as Johnson-Nyquist noise, is an electric noise produced by the thermal agitation of electrons in conductors and semiconductors. It is a random noise that occurs due to the movement of charge carriers (electrons) in response to temperature. The amplitude of thermal noise increases with temperature and bandwidth and is a fundamental aspect of electronic systems. The other options are different types of noise: A. External noise: Refers to noise introduced from external sources into a system. B. Internal noise: Could be a generic term for noise generated within a system but is not as specific as thermal noise. D. Flicker: Typically refers to variations in brightness or amplitude in a signal and is not directly associated with the thermal agitation of electrons. Therefore, the correct answer is C. Thermal noise. 25. Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N? A. 5.23 dB B. 14.77 dB C. 30 dB D. 40 dB View Answer: Answer: Option A Solution: 26. The noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB? A. 11.59 dB B. 11.23 dB C. 10.79 dB D. 10.5 dB View Answer: Answer: Option C Solution: What is the over all noise figure Solution: 27. Is the interference coming from other communications channels? A. Jitter B. Crosstalk C. RFI D. EMI View Answer: Answer: Option B Explanation: Crosstalk is the phenomenon where signals from one communication channel interfere with signals in an adjacent or nearby channel. It can lead to signal distortion and impact the overall performance of a communication system. Crosstalk is a common concern, especially in systems where multiple channels are closely packed or share common pathways. The other options represent different types of interference: A. Jitter: Jitter refers to variations in the timing of a signal and is not specifically associated with interference from other communication channels. C. RFI (Radio Frequency Interference): RFI generally involves unwanted signals from external sources affecting a communication system. D. EMI (Electromagnetic Interference): EMI is interference caused by electromagnetic signals, which can come from various sources. Therefore, in the context of interference from other communications channels, the correct answer is B. Crosstalk. 28. What is the reference noise level? A. 10 pW B. 0 dBm C. 1mW D. -90 dBm View Answer: Answer: Option D Explanation: The unit dBm (decibels referred to one milliwatt) is commonly used as a reference for power levels in electronic communication systems. A reference noise level of -90 dBm indicates the power level in decibels relative to one milliwatt. In this context, it is often used to quantify the strength of signals or noise in a system. The other options represent different power levels or units: A. 10 pW: This is a power level measured in picowatts. B. 0 dBm: This represents the reference level itself, as 0 dBm is equivalent to one milliwatt. C. 1 mW: This is a power level of one milliwatt. Therefore, the correct answer for the reference noise level is D. -90 dBm. 29. What is the unit of noise power of psophometer? A. pWp B. dBa C. dBm D. dBrn View Answer: Answer: Option A Solution: 30. A large emission of hydrogen from the sun that affects communications. A. Solar flare B. Cosmic disturbance C. Ballistic disturbance D. Solar noise View Answer: Answer: Option A Explanation: A solar flare is a sudden, intense burst of energy on the Sun’s surface, often accompanied by the release of a large amount of hydrogen and other ions. This emission of charged particles can affect the Earth’s ionosphere, leading to disturbances in radio communication, especially in the high-frequency (HF) bands. Solar flares can cause increased ionization in the Earth’s atmosphere, affecting the propagation of radio waves and leading to communication disruptions. The other options do not specifically describe the phenomenon of a large emission of hydrogen from the Sun: B. Cosmic disturbance: A broad term that might refer to disturbances from various cosmic sources but is not specific to solar emissions. C. Ballistic disturbance: This term typically relates to the motion of projectiles and is not associated with solar phenomena. D. Solar noise: While solar activity can contribute to noise in communication systems, the term “solar noise” is not as specific to the large emission of hydrogen from the Sun. Therefore, the correct answer is A. Solar flare. 31. Atmospheric noise is known as _______noise. A. static B. cosmic C. solar D. lunar View Answer: Answer: Option A Explanation: Atmospheric noise, also known as static noise, refers to unwanted electrical signals generated by natural atmospheric processes. This type of noise includes various disturbances caused by lightning, precipitation, and other atmospheric phenomena. Atmospheric noise can impact communication systems, especially in radio frequency (RF) applications, introducing random variations in the received signals. The other options are associated with different types of noise: B. Cosmic noise: Noise originating from extraterrestrial sources, such as cosmic radiation. C. Solar noise: Noise caused by solar activity, which can affect communication systems. D. Lunar noise: Noise associated with the Moon, typically not a significant factor in terrestrial communication systems. Therefore, the correct answer is A. static noise. 32. Standard design reference for environmental noise temperature. A. 300K B. 290K C. 32˚F D. 212˚F View Answer: Answer: Option B Explanation: The reference noise temperature is a standard used in calculating thermal noise (Johnson-Nyquist noise) in electronic systems. The commonly accepted value for this reference temperature is 290 Kelvin (K). This temperature is chosen as a standard for consistency in thermal noise calculations across various applications and industries. 33. Absolute temperature in Kelvin. A. ˚C + 273 B. ˚C + 75 C. ˚C + 19 D. ˚C + 290 View Answer: Answer: Option A Explanation: The Kelvin scale is an absolute temperature scale with 0 K representing absolute zero. To convert a temperature from degrees Celsius to Kelvin, you add 273.15 (commonly approximated to 273 for simplicity). Therefore, the correct expression is ˚C + 273. 34. If bandwidth is doubled, the signal power is _________. A. not changed B. quadrupled C. tripled D. doubled View Answer: Answer: Option A Solution: 35. Name one or more sources of noise bearing on electronic communications. A. Steam boiler B. Galaxies C. Internal combustion engine D. Both B and C View Answer: Answer: Option D Explanation: Sources of noise in electronic communications include: B. Galaxies: Cosmic noise, which includes noise from extraterrestrial sources like galaxies, can impact electronic communications. C. Internal combustion engine: The operation of internal combustion engines can introduce electromagnetic interference (EMI) into electronic communication systems. A. Steam boiler: While a steam boiler may produce acoustic noise, it is not typically a significant source of electromagnetic noise that directly affects electronic communications. Therefore, the correct answer is D. Both B and C. 36. The transmitter technique adopted to reduce the noise effect of the preceding question is called A. noise masking B. anitnoise C. noise killing D. preemphasis View Answer: Answer: Option D Explanation: Preemphasis is a transmitter technique used to reduce the impact of noise in electronic communications. It involves increasing the amplitude of higher-frequency components of the signal before transmission. This adjustment in signal amplitudes helps compensate for the expected attenuation of these higher frequencies during transmission, improving the signal-to-noise ratio at the receiver. 37. Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? A. dc B. low C. intermediate D. high View Answer: Answer: Option D Explanation: The purpose of deemphasis is to compensate for the preemphasis applied at the transmitter, which boosts higher-frequency components of the signal to improve the signal-to-noise ratio during transmission. Deemphasis is performed at the receiver to restore a more natural frequency balance and reduce the emphasis on higher frequencies introduced during transmission. 38. Atmospheric noise or static is not a great problem A. at frequencies below 20 MHz B. at frequencies below 5 MHz C. at frequencies above 30 MHz D. at frequencies above 1 MHz View Answer: Answer: Option C Solution: 39. What is the proper procedure for suppressing electrical noise in a mobile station? A. Apply shielding and filtering where necessary B. Insulate a all plain sheet metal surfaces from each other C. Apply anti-static spray liberally to all nonmetallic D. Install filter capacitors in series with all dc wiring View Answer: Answer: Option A Explanation: Shielding: Shielding involves enclosing sensitive components or wiring in a conductive material (like metal) to prevent external electromagnetic interference from reaching them and to contain the emitted signals within. Filtering: Filtering is the process of using electronic components such as capacitors and inductors to attenuate unwanted signals or noise within a specified frequency range. Filters are applied to eliminate or reduce noise at specific frequencies. Options B and C are not standard practices for suppressing electrical noise in a mobile station: Option B: While insulating sheet metal surfaces may have other purposes, it doesn’t directly address electrical noise suppression. Option C: Applying anti-static spray to nonmetallic surfaces is primarily for static discharge prevention and may not effectively suppress electrical noise. Option D is also not a comprehensive solution: Option D: Installing filter capacitors in series with all DC wiring may help with DC filtering, but it might not address higher-frequency noise or electromagnetic interference. Therefore, the correct answer is A. Apply shielding and filtering where necessary. 40. Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150MHz) marine-band receiver? A. Man-made noise B. In the atmosphere C. In the receiver front end D. In the ionosphere View Answer: Answer: Option C Explanation: In a VHF marine-band receiver, the dominant noise source is often the receiver itself, particularly in the front end. The receiver front end includes components such as amplifiers, mixers, and filters. The electronic components in this section contribute to thermal noise and other forms of internal noise that can impact the overall signal-to-noise ratio. While man-made noise (option A) and atmospheric noise (option B) can be factors, in many VHF applications, the internal noise generated within the receiver front end is a significant contributor to the overall noise level in the system. Therefore, the correct answer is C. In the receiver front end. 41. The difference between signal strength at a given point and a reference level is________. A. power B. dBm C. level D. ratio View Answer: Answer: Option C Explanation: In the context of signal strength measurements, the term “level” is often used to describe the magnitude of a signal relative to a reference point. It doesn’t specify the unit of measurement but indicates the strength or intensity of the signal at a particular location compared to a reference level. Therefore, the correct answer is C. Level. 42. Interfering effect of noise, C message weighted, is _________. A. dBa B. dBm C. dBmc D. dB View Answer: Answer: Option C Explanation: The term “dBmc” refers to a measurement in decibels with C-weighting applied. The C-weighting is another type of frequency weighting used in noise measurements. It is often used in industrial and commercial noise assessments where lower-frequency noise components are more relevant. Therefore, the correct answer, considering the context, is C. dBmc. 43. F1A weighting refers to ___________. A. -90 dBm B. dBrnc0 C. dBrnc D. F1A handset View Answer: Answer: Option C Explanation: F1A weighting, often denoted as dBrnc, refers to a specific type of noise measurement with weighting applied. The “F” in F1A stands for “Federal,” and it is part of the Federal Information Processing Standard (FIPS) for noise measurement. The term “dBrnc” signifies the measurement in decibels relative to the reference noise level with C-weighting applied. Therefore, the correct answer is C. dBrnc. 44. Reading a 58 dBrnC on your Western Electric 3A test set at a +7 test point is equal to ______ dBrnc0. A. 58 B. 51 C. 65 D. 27 View Answer: Answer: Option B Solution: Solution: Reading a 58 dBrnC on your Western Electric 3A test set at a +7 test point 45. Reading a 58 dBrn, at a +7 test point is equal to ________ dBa0. A. 26 B. 65 C. 51 D. 46 View Answer: Answer: Option D Solution: Solution: Reading a 58 dBrn, at a +7 test point is equal to ________ dBa0 46. A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair equals _____ dB of crosstalk coupling. A. 20 B. 30 C. 60 D. 25 View Answer: Answer: Option B Solution: Solution: A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair 47. Power is __________. A. actual amount of power reference to 1mW B. logarithmic ratio of two powers C. definite amount of energy per time period D. current flow per time period View Answer: Answer: Option C Explanation: Power is the rate at which energy is transferred or the rate at which work is done. It is defined as the amount of energy transferred or converted per unit time. Mathematically, power (P) is given by the formula: P = W/t where W is the amount of energy and t is the time period. 48. 15 dBa F1A weighted, equals ___________. A. -90 dBm B. -82 dBm C. -85 dBm D. -70 dBm View Answer: Answer: Option D Solution: 49. You are measuring noise in a voice channel with a Lenkurt 601A, F1A weighting network and a flat meter. Your meter reads -47 dBm. What is this reading in dBa? A. 77 dBa B. 35 dBa C. 38 dBa D. 32 dBa View Answer: Answer: Option C Solution: 50. You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -57 dBm. This is ________dBa0. A. 20 B. 15 C. 25 D. 17 View Answer: Answer: Option C Solution: