Description : A 4.5-MHz signal which is equal to the difference between the picture and sound RF carrier frequencies in a 6-MHz TV channel.
Last Answer : Intercarrier frequencY
Description : The modulated picture carrier wave includes the composite video signal as the:
Last Answer : Symmetric envelope of amplitude variations
Description : The bandwidth required for a modulated carrier depends on:
Last Answer : the baseband frequency range
Description : If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be
Last Answer : 50
Description : It is a system where the digital signals are placed directly on the coaxial cable.
Last Answer : Baseband
Description : In an amplitude modulated waveform, the amplitude of the sideband is
Last Answer : 1/2 carrier amplitude x modulation index
Description : In an AM transmitter with 100% modulation, the voltage of the final RF stage will be
Last Answer : approximately four times the DC supply voltage
Description : In a TV receiver the raster is normal but there is no sound and quality of picture is poor. The defective part is
Last Answer : AGC, video IF amplifier, RF amplifier
Description : The time it takes a light induced carrier travel across the depletion region of the semiconductor.
Last Answer : . transit time
Description : A carrier recovery is needed with:
Last Answer : DPSK
Description : Carrier is A. One or more conductors that serve as a common connection for a related group of devices B. a continuous frequency capableof being modulated or impressed witha second signal C. ... that provides a data communications service among stations attached tothe network E. None of the above
Last Answer : a continuous frequency capableof being modulated or impressed witha second signa
Description : Emphasizing low-level signals and compressing higher level signals is called:
Last Answer : companding
Description : Image frequencies occur when two signals ____.
Last Answer : enter the mixer, one below and one above the local oscillator by a difference equal to the IF
Description : It is the most prevalent encoding technique used for TDM signals:
Last Answer : PCM
Description : Pulse – amplitude modulation signals are multiplexed by using
Last Answer : FET switches
Description : The most common method used for sampling voice signals in PCM systems.
Last Answer : flat top sampling
Description : In a star-topology Ethernet LAN, _______ is just a point where the signals coming from different stations collide; it is the collision point.
Last Answer : a passive hub
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 : How long does it take to scan 2 picture elements when 400 are scanned in 50 microseconds?
Last Answer : 0.25 microsec
Description : Picture frames are repeated at the rate of ___ per second
Last Answer : . 30
Last Answer : 30
Description : An image uses 512 x 512 picture elements. Each element can take any of eight distinguishable levels. The maximum entropy in the above image will be:
Last Answer : 786432 bits
Description : In the ________ traffic model, the rate of the data flow changes in time, with the changes smooth instead of sudden and sharp.
Last Answer : variable bit rate
Description : IEEE has defined the specifications for a wireless LAN, called _______, which covers the physical and data link layers.
Last Answer : . IEEE 802.11
Description : A popular light wavelength fiber-optic cable is
Last Answer : 1.3 micrometer
Description : Single-mode step-index cable has a core diameter in the range of
Last Answer : 2 to 15 micrometer
Description : The upper pulse rate and information carrying capacity of a cable is limited by:
Last Answer : modal dispersion
Description : Which type of fiber-optic cable is the most widely used?
Last Answer : multimode step-index
Description : Which type of fiber-optic cable has the least modal dispersion?
Last Answer : single-mode step index
Description : ____ system transmits frequency-division-multiplexed voice band signals over a coaxial cable for distances up to 4000 miles. A. T carrier B. X carrier C. L carrier D. F carrier
Last Answer : C. L carrier
Description : The sound IF in a TV receiver is
Last Answer : 41.25 MHz
Description : It is proposed network designed by major telephone companies in conjunction with the ITU-T with the intent of providing worldwide telecommunications support for voice, data, video and facsimile information within the same networ
Last Answer : ISDN
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 : The reason a CSMA/CD network has a minimum length for packets is:
Last Answer : to make sure all other nodes hear a collision in progress
Description : Packets which is self – contained and travels through the network independent of other packets of the same message by whatever means available
Last Answer : Datagram
Description : In IPv6, when a datagram needs to be discarded in a congested network, the decision is based on the _______ field in the base header.
Last Answer : priority
Description : Congestion in a network or internetwork occurs because routers and switches have _______
Last Answer : queues
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 : A 400 W carrier is amplitude modulated to a depth of 75%.Calculate the total power in AM wave. (i) Explain the types of noise in a communication system. (ii) Compare simplex and duplex mode of communication.
Last Answer : (i) Noise: Noise is any spurious or undesired disturbances that mask the received signal in a communication system. a) Atmospheric Noise: Atmospheric Noise is also known as static noise which is the ... remote control ExamplesWalkytalky,telephone,mobile,Radar, FAX,Pager 4
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 : Which of the following is not a baseband signal modulation? A. RF carrier B. Video System C. Audio signal D. Binary coded pulses
Last Answer : A. RF carrier
Description : A 1000W carrier is amplitude modulated to a depth of 85%. Calculate the total power of the modulated wave? A. 1361.25 W B. 680.62 W C. 1425 W D. 712.5 W
Last Answer : A. 1361.25 W
Description : A 1 Mhz carrier is amplitude modulated by a pure 200-Hz audio test tone. Which of the following combinations of frequencies represent the total content of the AM signal? A. 1 MHz and 200 Hz B. 1 MHz and 1000.2 kHz C. 999.8 kHz, 1000 kHz, and 1000.2 kHz D. 999.8 kHz and 1000.2 kHz
Last Answer : C. 999.8 kHz, 1000 kHz, and 1000.2 kHz
Description : What is meant by the term modulation index? A. The processor index. B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. C. The FM signal-to-noise ratio. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.
Last Answer : B. The ratio between the deviation of a frequency modulated signal and the modulating frequency.
Description : What is the first symbol of a radio signal transmission having an amplitude modulated signal carrier, double side band? A. C B. B C. H D. A
Last Answer : D. A
Description : Refers to the first symbol in an emission designation with an amplitude modulated main carrier represented by letter H. A. Single sideband suppressed carrier B. Double sideband full carrier C. Independent sideband D. Double sideband
Last Answer : B. Double sideband full carrier
Description : In amplitude modulation technique the unmodulated carrier is referred to as having ______. A. 100% modulation B. 0% modulation C. 50% modulated D. Over modulated
Last Answer : B. 0% modulation
Description : Modulation in which the modulated wave is always present. A. Carrier modulation B. Front-end C. Continuous modulation D. Log-periodic modulation
Last Answer : C. Continuous modulation