CDC 2e151 Satellite, Wideband, And Telemetry Systems Journeyman Volume 1

Coordinated Universal Time (UTC) is based on a 24-hour clock system. This system divides a day into 24 equal parts, with each part representing one hour. UTC is used as a standard time reference around the world, allowing for consistent timekeeping and coordination across different time zones. The use of a 24-hour clock system ensures clarity and avoids confusion between AM and PM designations.

When sodium and mercury vapor lights stop working while the power is still applied, they can cause electromagnetic interference noise bursts. The best way to eliminate this interference is by changing the bulb. By replacing the faulty bulb with a new one, the electromagnetic interference caused by the malfunctioning light will be resolved.

The Air Force wants electromagnetic interference problems resolved at the level of the affected unit. This means that the responsibility for addressing and resolving these problems lies with the specific unit that is experiencing the interference. They are expected to take appropriate measures to mitigate the interference and ensure that their operations are not affected. This approach allows for a more localized and efficient resolution of the issue, as the unit directly impacted by the interference is best positioned to understand and address the problem.

The core of a fiber optic cable is the central region through which light is transmitted. It is made of a highly transparent material with a high refractive index, allowing the light to propagate through it by total internal reflection. The cladding, coating, and buffer layers surround and protect the core, but they do not serve as the primary optical transmission path. Therefore, the core is the correct answer.

Multiplexing refers to the process of combining multiple signals into a single transmission path. This allows for more efficient use of the available bandwidth and resources. By combining multiple signals, it is possible to transmit more information simultaneously over a single transmission path, increasing the overall capacity and efficiency of the system. This is commonly used in telecommunications and networking to optimize the use of limited resources and improve data transmission efficiency.

The signals originating from the satellite that we use to acquire and track the satellite are called beacons. Beacons are specific signals transmitted by the satellite that serve as a reference point for tracking and locating the satellite. By receiving and analyzing the beacon signals, we can determine the satellite's position, velocity, and other important parameters necessary for tracking and acquiring the satellite.

Solar time is based on the apparent motion of the sun in the sky. It is determined by the position of the sun relative to an observer's location on Earth. As the Earth rotates on its axis, the sun appears to move across the sky, causing shadows to shift and indicating the passage of time. This natural movement of the sun serves as the basis for solar time, which is used to set clocks and determine local time in different regions.

In order to successfully upload satellite control data, track ballistic missiles, and predict satellite tracking coordinates, all parties involved must have synchronized timing. This means that they need to have their clocks set to the same time and be able to coordinate their actions and communications based on this synchronized timing. Having synchronized timing ensures that all parties are operating on the same schedule and can effectively carry out these missions.

Broadband transmitter noise refers to unwanted signals that are spread across a wide range of frequencies. To eliminate this noise, a band pass filter can be used. A band pass filter allows only a specific range of frequencies to pass through while attenuating frequencies outside of that range. By using a band pass filter, the desired signal within the specific frequency range can be transmitted effectively while blocking out the unwanted noise. This helps in improving the overall signal quality and reducing interference.

Troposcatter losses refer to the attenuation of radio signals due to scattering in the troposphere. During winter nights, the atmosphere is typically more stable, which leads to stronger temperature inversions. These inversions cause the radio signals to be trapped closer to the ground, resulting in increased scattering and higher losses. Therefore, troposcatter losses are usually worse during winter nights.

When computing satellite look angles, ground distance on the earth's surface is expressed in degrees. This is because look angles are used to determine the direction in which a satellite needs to be pointed from a specific location on Earth. Ground distance is measured in degrees of latitude and longitude, which are the standard units for expressing locations on the Earth's surface. Degrees provide a precise and standardized way to calculate the angle and direction of the satellite in relation to the ground.

When any frequency source, regardless of its accuracy or stability, is used as the sole calibration reference for other frequency sources, it is considered a primary standard. A primary standard is the highest level of calibration reference and is used to establish the accuracy and stability of other frequency sources. It serves as the ultimate reference for calibration and is typically traceable to national or international standards.

A conformal airborne antenna can be designed into any part of an aerospace vehicle's surface, such as the fuselage or wings, without affecting its aerodynamic properties. Unlike other types of antennas like fixed blade or whip antennas, which protrude from the surface and can cause drag, a conformal antenna is integrated seamlessly into the vehicle's shape. This allows for improved aerodynamic performance while still maintaining the functionality of the antenna.

An atomic time scale could be based on the frequency of a cesium oscillator. Cesium atomic clocks work by measuring the vibrations of cesium atoms, which have a very stable and consistent frequency. This frequency is used as a reference to accurately measure time. Cesium atomic clocks are widely used in scientific research, telecommunications, and other applications where precise timekeeping is essential.

The refractive index of air is influenced by two factors: atmospheric pressure and temperature. Atmospheric pressure affects the density of air, which in turn affects the speed of light as it passes through the air. As the pressure increases, the refractive index also increases. Temperature, on the other hand, affects the speed of molecules in the air, which can cause variations in the refractive index. Therefore, both atmospheric pressure and temperature play a role in determining the refractive index of air.

The correct answer is meridian. To determine the number of hours coordinated universal time (UTC) differs from your local time, you need to consider the number of time zones between your location and the location of the zero meridian. The zero meridian, also known as the Prime Meridian, is the line of longitude that passes through Greenwich, London, and serves as the reference point for measuring time zones. By calculating the time difference between your location and the zero meridian, you can determine the number of hours UTC differs from your local time.

The correct answer is "Shield". In an exterior system, electromagnetic pulse coupling can occur through imperfectly sealed personnel access doors and equipment hatches, as well as improper installation of penetrating conductor protection. A shield is designed to provide protection against electromagnetic interference by creating a barrier between the external environment and the sensitive electronic components inside. It prevents the coupling of electromagnetic pulses into the system by blocking or redirecting them.

The correct answer is 1 because a general-purpose interface bus can only support one active talker at a time. This means that only one device can transmit data on the bus while others listen. Having multiple active talkers simultaneously can lead to data collisions and communication errors. Therefore, the maximum number of active talkers on a general-purpose interface bus is limited to one.

The general-purpose interference bus lines that ensure data transfer integrity are handshake lines. Handshake lines are used to establish communication between devices and ensure that data is transferred accurately and without errors. These lines allow devices to exchange control signals to indicate when they are ready to send or receive data, ensuring that the data transfer occurs smoothly and without interference.

The correct answer is Troposphere. The troposphere is the lowest layer of the Earth's atmosphere where weather occurs. It is the layer closest to the Earth's surface and extends from the surface up to about 8-15 kilometers. In this layer, temperature decreases with altitude and most of the Earth's weather phenomena, such as clouds, precipitation, and storms, take place. The other options, stratosphere, ionosphere, and mesosphere, are higher layers of the atmosphere where weather phenomena are not as prominent as in the troposphere.

When you are reasonably sure electromagnetic interference exists, the best course of action is to systematically gather data for analysis. This involves collecting relevant information and conducting a thorough investigation to identify the source and extent of the interference. By systematically gathering data, you can analyze the problem more effectively and make informed decisions on how to mitigate or resolve the interference. This approach allows for a more comprehensive understanding of the issue and increases the chances of finding a suitable solution.

The size of a waveguide is determined by the operating frequency. The operating frequency of a waveguide refers to the range of frequencies at which it can effectively transmit electromagnetic waves. Different frequencies require different physical dimensions for the waveguide to function optimally. Therefore, the size of the waveguide is directly related to the operating frequency it is designed to accommodate.

A laser emits coherent light. Coherent light is light that has a fixed phase relationship between its waves, meaning that all the waves are aligned and have the same frequency and wavelength. This results in a concentrated, narrow beam of light that can travel long distances without spreading out or losing intensity. In contrast, incoherent light consists of waves with random phases and directions, while ordinary light is a combination of different wavelengths and directions. Invisible light refers to wavelengths that are outside the visible spectrum and cannot be seen by the human eye.

The correct answer is milliwatt range. Laser power coupling refers to the process of transferring power from an external source into a laser system. The power coupling is measured in milliwatts, which is a unit of power equal to one thousandth of a watt. This suggests that the power being transferred is relatively low, indicating that the laser system being used operates at a milliwatt power range.

The inclination angle of a polar orbit is 90°. A polar orbit is an orbit that passes over or near the Earth's poles, and it is inclined at 90° to the equator. This means that the satellite or spacecraft in a polar orbit will pass over or near the North and South poles on each orbit. The inclination angle determines the path of the orbit and the coverage of the satellite, and a 90° inclination means that the orbit is perpendicular to the equator.

The resonant frequency of a quartz oscillator can drift due to two factors: temperature and aging. Temperature changes can cause the quartz crystal to expand or contract, affecting its resonant frequency. Aging refers to the gradual degradation of the quartz crystal over time, which can also cause the resonant frequency to drift. Humidity and operating frequency are not directly related to the drift of a quartz oscillator's resonant frequency.

Aircraft antennas are housed inside nonconductive radomes to protect them from the elements and to minimize interference with the aircraft's structure. These radomes are mounted outside or flush with the fuselage to ensure that the antennas have a clear line of sight for optimal signal reception and transmission. Using nonconductive materials for the radomes helps to prevent electrical interference and ensures that the antennas can operate effectively.

The correct answer is "Optimizing the antenna’s radiating pattern for its application." This answer explains that the location and orientation of an antenna on an aircraft are determined by the need to optimize its radiating pattern for its specific purpose or application. This suggests that the positioning of the antenna is based on factors such as the desired coverage area, signal strength, and interference avoidance, rather than being determined by the type of aircraft propulsion or power system, or a requirement for a 360° radiating pattern.

Ducting refers to the phenomenon of signal loss caused by temperature inversions in the atmosphere. During temperature inversions, the air near the ground is cooler than the air above it, which creates a layer of dense air that acts as a barrier for radio waves. This barrier causes the signals to be trapped and travel along the Earth's surface, resulting in signal loss. This effect is known as ducting, and it is a common occurrence in certain atmospheric conditions.

The correct answer is "atoms release energy at a particular resonant frequency." This explanation is based on the principle of atomic clocks, which rely on the vibrations of atoms to measure time accurately. When atoms absorb energy, they move to a higher energy state. As they return to their original state, they release energy in the form of electromagnetic radiation at a specific frequency. By measuring this resonant frequency, atomic clocks can maintain precise and consistent timekeeping.

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Without a detailed test and evaluation, we cannot draw reliable conclusions about the nature and degree of specific system susceptibility because all high-altitude electromagnetic pulse vulnerabilities may not be identified. This means that there could be potential vulnerabilities in the system that we are unaware of, making it difficult to accurately assess its susceptibility to electromagnetic pulses. Therefore, a detailed test and evaluation is necessary to ensure a comprehensive understanding of the system's vulnerabilities and level of susceptibility.

When a receiver responds to off-frequency signals, it is experiencing spurious responses. Spurious responses refer to unwanted or unintended signals that interfere with the desired signal reception. These signals can be caused by various factors such as nearby electronic devices, electromagnetic radiation, or poor signal filtering. Spurious responses can disrupt the proper functioning of the receiver and affect the quality and accuracy of the received signals.

Semiconductor laser diodes are well suited for fiber-optic modems because they can generate a focused and coherent beam of light that can travel long distances through the fiber-optic cables without significant loss of signal quality. They also have a high modulation bandwidth, allowing for efficient transmission of data. Additionally, semiconductor laser diodes can operate at high speeds and have a small form factor, making them ideal for use in compact and high-performance fiber-optic modems.

To have adequate signal strength at the receiver, the efficiency of the transmitting and receiving antennas must be high. This means that the antennas are able to effectively capture and transmit the signals without significant loss or degradation. If the antennas have low efficiency, it means that a significant portion of the signal is lost during transmission, resulting in a weaker signal at the receiver. Therefore, for the receiver to receive a strong signal, it is important for the antennas to have high efficiency.

Refraction is the bending of radio waves as they pass from one medium to another with a different density. This bending occurs due to the change in the speed of the waves as they enter the new medium. Diffusion refers to the spreading out of waves in different directions, while diffraction is the bending of waves around obstacles or through small openings. Reflection is the bouncing back of waves when they encounter a boundary. Therefore, the correct answer is refraction.

The amount of westward shift of a satellite is determined by its period. The period of a satellite is the time it takes to complete one orbit around the Earth. A shorter period means the satellite completes its orbit faster, resulting in a greater westward shift. Conversely, a longer period means the satellite takes more time to complete its orbit, resulting in a smaller westward shift. Therefore, the period of the satellite directly influences the amount of westward shift it experiences.

The ephemeris data contains information about the predicted satellite orbit. This means that it provides details about the satellite's position and trajectory in space at different times. The data helps in tracking and predicting the movement of the satellite, which is crucial for various applications such as satellite navigation, communication, and scientific research. It does not provide information about atmospheric conditions, available satellite channels, or ground station combinations.

The correct answer is "Service Request." The three general-purpose interface bus handshake lines are "Not Ready for Data," which indicates that the receiving device is not ready to accept data; "Data Valid," which indicates that the data being transmitted is valid; and "Service Request," which is a signal sent by the receiving device to request service from the sending device. "End or Identify" and "Ring-back Invalid" are not valid terms used in the context of general-purpose interface bus handshake lines. "Not Data Accepted" is not a correct term for one of the handshake lines.

The Straight Tip (ST) fiber-optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected. This type of connector provides a secure and stable connection, making it suitable for applications where stability is important. The quick-release feature allows for easy installation and removal, while the keyed bayonet couplings ensure proper alignment and prevent accidental disconnection.

The MIL-STD 1553 coupling technique that requires a separate bus coupler unit is the transformer. Transformers are used to couple the bus to the terminals in the system, providing electrical isolation and impedance matching. This allows for effective communication between the bus and the terminals while minimizing signal distortion and interference. The other options, direct, mini stub, and short stub, do not require a separate bus coupler unit as they are different coupling techniques that do not involve the use of transformers.

The correct answer is Radiated: antennas and boresite feedhorns. This means that the electromagnetic pulse (EMP) in the radiated source region has a primarily vertical electric field, and it affects antennas and boresite feedhorns. The EMP can induce strong electric currents in these structures, potentially damaging or disrupting their operation.

Wavelength division multiplexing (WDM) is a technique used in optical communication systems to combine multiple optical signals onto a single optical fiber by assigning each signal to a specific frequency of light. This allows for the simultaneous transmission of multiple signals over the same fiber, increasing the overall capacity of the system. Therefore, the correct answer is frequency of light.

Space waves are used mainly for line-of-sight communications. Line-of-sight refers to the direct path between the transmitter and receiver without any obstruction. Space waves propagate in a straight line from the transmitting antenna to the receiving antenna, making them ideal for line-of-sight communication. Sky waves are used for long-distance communication via reflection off the ionosphere, earth waves are used for communication over short distances along the Earth's surface, and ground waves are used for communication over long distances along the Earth's surface.

The major axis is the longest distance across an elliptical orbit. In an ellipse, the major axis is the line that passes through the center of the ellipse and is the longest distance from one side of the ellipse to the other. This is in contrast to the minor axis, which is the shortest distance across the ellipse. Apogee and perigee, on the other hand, refer to the points in an orbit where an object is farthest and closest to the body it is orbiting, respectively.

High-altitude electromagnetic pulse (HEMP) is a wideband phenomenon that involves a frequency range from 1 Hz to 1 GHz. It is a type of electromagnetic pulse that occurs as a result of a nuclear explosion in the Earth's atmosphere. HEMP can cause significant damage to electronic systems and infrastructure over a wide range of frequencies, hence the term "wideband". The correct answer, "Wideband; 1 Hz to 1 GHz", accurately describes the frequency range and type of phenomenon associated with HEMP.

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When the transmitted signal experiences a large attenuation, it means that the signal weakens significantly during transmission. This causes the signal-to-noise ratio to fall below unity, meaning that the level of noise in the signal becomes stronger compared to the actual transmitted signal. As a result, the communication becomes difficult or impossible to decipher, leading to a communications blackout.

The closest point of orbit that a satellite comes to the Earth is called the perigee. This term is commonly used in astronomy and space science to describe the point in an orbit where the distance between the satellite and the Earth is at its minimum. The opposite of perigee is apogee, which refers to the point in the orbit where the satellite is farthest from the Earth. The terms major axis and minor axis are not directly related to the closest point of orbit and are more commonly associated with the shape of an ellipse.

Waveguides are capable of handling more power than coaxial lines because they have an air-over path twice as long. This longer path reduces the power losses due to resistance, allowing the waveguide to handle higher power levels. The longer path also helps in reducing signal attenuation and interference, making waveguides more efficient for power transmission compared to coaxial lines.