Description : What term is used to describe a spread spectrum communications system in which a very fast binary bit stream is used to shift the phase of an RF carrier? A. Frequency hopping B. Direct sequence C. Binary phase-shift keying D. Phase compandored spread spectrum
Last Answer : B. Direct sequence
Description : What is the term used to describe a spread spectrum communications system where the center frequency if a conventional carrier is altered many time per second in accordance with a pseudo ... hopping B. Direct sequence C. Time-domain frequency modulation D. Frequency compandored spread spectrum
Last Answer : A. Frequency hopping
Description : The most critical and difficult part of receiving a direct – sequence spread spectrum signal is :
Last Answer : Synchronism
Description : To a conventional narrowband receiver, a spread spectrum signal appears to be
Last Answer : Noise
Description : Not a benefit of spread spectrum?
Last Answer : Noise proof
Description : Explain direct sequence spread spectrum (DSSS) transmitter with block diagram.
Last Answer : In direct sequence, the serial binary data is mixed with a higher frequency pseudorandom binary code at a faster rate and the result is used to phase-modulate a carrier. The ... 1010 with odd parity. le of spread spectrum modulation and demodulation using PSK for primary modulation.
Description : It is logically equivalent to making telephone call through the DDD network except no direct end-to-end connection is made
Last Answer : Virtual call
Description : A special type of transmission line that consist of conducting metallic tube through which high frequency electromagnetic energy is propagated
Last Answer : waveguide
Description : In a waveguide, what is a frequency that would cause angles of incidence and reflection to be zero degrees?
Last Answer : Critical Frequency
Description : At what frequency compared to the cutoff frequency of a waveguide will the wavefronts be reflected back and forth across the guide (setting up standing waves) and no energy
Last Answer : UHF receiving antenna
Description : In changing the frequency of a cavity, what is accomplished by placing a nonmagnetic slug in the area of maximum H lines
Last Answer : Inductive Coupling
Description : When microwave energy is passed through a piece of ferrite in a magnetic field, another effect occurs. If the frequency of the microwave energy is much greater than the electron wobble frequency, the plane of polarization of the wavefront is rotated. This is known as
Last Answer : Faraday Rotation Effect
Description : The vertical field-scanning frequency is ______ Hz
Last Answer : 60
Description : In the Philippine color television system, the intercarrier frequency, in MHz, is
Last Answer : 4.5
Description : The result whenever the sampling rate is less than twice the highest audio frequency.
Last Answer : alias
Description : An FDM hierarchy which is formed by frequency – division multiplexing 10 super groups together for a combined capacity of 600 voice band message channels.
Last Answer : Mastergroup
Description : An FDM hierarchy which is formed by frequency – division multiplexing five groups containing 12 channels each for a combined bandwidth of 240 kHz
Last Answer : Supergroup
Description : “When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted”
Last Answer : Plank’s law
Description : What is the frequency limit of a copper wire?
Last Answer : approximately 1.0 MHz
Description : In communication systems the frequency range used for voice is:
Last Answer : 300 Hz to 3800 Hz
Description : The best frequency demodulator is the:
Last Answer : PLL discriminato
Description : Approximately what is the frequency limit of the optical fiber?
Last Answer : 40 GHz
Description : What is a device that provides a method of sampling energy from within a waveguide for measurement or use in another circuit?
Last Answer : Directional Coupler
Description : What circuit in the TV receiver is used to develop the high voltage needed to operate the picture tube?
Last Answer : Horizontal output
Description : An integrated circuit that performs the PCM encoding and decoding functions
Last Answer : Codec
Description : A virtual circuit which is logically equivalent to a two-point dedicated private-line circuit except slower
Last Answer : Permanent Virtual Circuit
Description : The main circuit in a PSN generator is ____.
Last Answer : Shift register
Description : ____ is a virtual-circuit wide-area network that was designed in response to demands for a new type of WAN in the late 1980s and early 1990s.
Last Answer : . Frame Relay
Description : The most common method used for sampling voice signals in PCM systems.
Last Answer : flat top sampling
Description : How can multiple earth stations share a satellite on the same frequencies? A. Frequency reuse B. Multiplexing C. Mixing D. Frequency hopping
Last Answer : A. Frequency reuse
Description : Which of the following scheme is used by Bluetooth? a) Frequency hopping TDD scheme b) Frequency hopping FDD scheme c) DSSS TDD scheme d) DSSS FDD scheme
Last Answer : a) Frequency hopping TDD scheme
Description : Explain fast frequency hopping techniques with suitable waveforms. State its advantage and disadvantages.
Last Answer : In Fast Frequency hopping multiple frequencies or hops are used to transmit one symbol. The hop rate is higher than symbol rate but chip rate is equal to hop rate For each symbol ... at receiver 3. Complex and expensive digital frequency synthesizers are required 4. Data rates are low
Description : It is the ratio of the power density radiated in a particular direction to the power density radiated to the same point by a reference antenna, assuming both antennas are radiating the same amount of power
Last Answer : directive gain
Description : Both LEDs and ILDs operate correctly with:
Last Answer : Forward bias
Description : How does one reconcile the left's commonsense narrative of manmade global warming with the History Channel's assertion that the world's 5 known Extremely Low Frequency (ELF) transmitters can "potentially alter the weather anywhere in the world"*?
Last Answer : this is why i wear a tinfoil hat
Description : What would happen if you plugged an FM transmitter into a radio's headphone jack and set the radio to the transmitter's transmitting frequency?
Last Answer : You would get a positive feedback loop, probably resulting in an audible tone. The amplitude would be limited by the transmitter’s modulation limiter, so all you’d have is a very ordinary oscillator.
Description : Why are frequency modulation transmitters more efficient? A. Because their power is increased by class C amplifiers B. Because their power is increased by class A amplifiers C. Because their power is increased by class B amplifiers D. Because their power is increased by class AB amplifiers
Last Answer : A. Because their power is increased by class C amplifiers
Description : When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage D. final RF stage
Last Answer : D. final RF stage
Description : The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization ___
Last Answer : is horizontal
Description : The property of interchangeability for the transmitting and receiving operations is known as ____
Last Answer : reciprocity
Description : The fields surrounding the antenna do not collapse their energy back into the antenna but rather radiate it out in space
Last Answer : radiation field
Description : It is the ratio of the radiated to the reflected energy:
Last Answer : Radiation efficiency
Description : It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates
Last Answer : . Radiation resistance
Description : Plots of field strength or power density with respect to the value at a reference point.
Last Answer : relative radiation pattern
Description : The radiation pattern plotted in terms of electric field strength or power density
Last Answer : absolute radiation pattern
Description : The line bisecting the major lobe, or pointing from the center of the antenna in the direction of maximum radiation is called _____
Last Answer : line of shoot
Description : If energy is applied at the geometrical center of antenna, the antenna is said to be ___
Last Answer : center-fed
Description : The radiation pattern of collinear and a broadside antenna is __
Last Answer : bidirectional