Description : In_____ transmission, the frequency of the carrier signal is modulated to follow the changing voltage level (amplitude)of the modulating signal. The peak amplitude and phase of the carrier signal remainconstant,but as ... of thecarrier changes correspondingly. A) AM B) PM C) FM D) none of the above
Last Answer : FM
Description : In_____ transmission, thephaseof the carrier signal is modulated to follow the changingvoltage level (amplitude) of the modulating signal. A) AM B) PM C) FM D) none of the above
Last Answer : PM
Description : One of the FM signal generator control which varies the phase of the modulating voltage applied to the oscillator of the sweep generator A. Band control B. Phase control C. Marker amplitude control D. Sweep output control
Last Answer : B. Phase control
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 : In________, the phase of thecarrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant. A) ASK B) PSK C) FSK D) QAM
Last Answer : PSK
Description : In FM, frequency of modulated wave varies with A. amplitude B. time C. wavelength D. energy
Last Answer : time
Description : Sound in TV is modulating - (1) AM (2) FM (3) PCM (4) PM
Last Answer : (1) AM
Description : What type of transmission is radiated from an aircraft’s radio altimeter antenna? A. An amplitude modulated continuous wave B. A pulse position modulated UHF signal C. A differential phase shift keyed UHF signal D. A frequency modulated continuous wave
Last Answer : D. A frequency modulated continuous wave
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 : What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. Interference to adjacent channel B. Higher fidelity C. Increase noise D. Higher audio signal
Last Answer : A. Interference to adjacent channel
Description : If the percentage modulation of an AM amplifier is 88% and the modulating signal is 1 volt, the carrier has an amplitude of _______________. A. 1.14 volts B. 0.88 volt C. 1.88 volts D. 0.12 volt
Last Answer : A. 1.14 volts
Description : What happens to an fm signal as you increase the frequency of the modulating signal?
Last Answer : Both the bandwidth and the number of significant sidebands increase.
Description : The modulation index of a FM Signal having modulating frequency 2 KHz and Max deviation is 10 KHz, is: - a) 2 b) 5 c) 3 d) 4
Last Answer : The modulation index of a FM Signal having modulating frequency 2 KHz and Max deviation is 10 KHz, is: - 5
Description : Which of the following is not an analog-to-analog conversion? A) AM B) PM C) FM D) QAM
Last Answer : QAM
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 : Amplitude of modulated wave is in phase with A. output B. system C. frequency D. signal
Last Answer : signal
Description : In a microwave test bench, why is the microwave signal amplitude modulated at 1 kHz? (1) To increase the sensitivity of measurement (2) To transmit the signal to a far-off place (3) To study amplitude modulation (4) Because crystal detector fails at microwave frequencies
Last Answer : In a microwave test bench, why is the microwave signal amplitude modulated at 1 kHz? Because crystal detector fails at microwave frequencies
Description : A 4 GHz carrier is amplitude modulated by a low-pass signal of maximum cut off frequency 1 MHz. lf this signal is to be ideally sampled, the minimum sampling frequency should be nearly
Last Answer : A 4 GHz carrier is amplitude modulated by a low-pass signal of maximum cut off frequency 1 MHz. lf this signal is to be ideally sampled, the minimum sampling frequency should be nearly 4 Ghz
Description : Thecarrier that handles intra-LATA services is calleda(n) _____ . A) POP B) IXC C) LEC D) none of the above
Last Answer : LEC
Description : The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, thesignal modulates another carrier frequency. A) FDM B) DSSS C) FHSS D) TDM
Last Answer : FHSS
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 : Contention 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 : the condition whentwo or more stations attempt to use the same channel at the same time
Description : n digital modulation, it is similar to standard amplitude modulation except there is only two amplitudes possible.
Last Answer : amplitude shift keying
Description : What is the approximate bandwidth of an FM system with 10 kHz of modulating frequency and a 150 kHz of frequency deviation? A. 300 kHz B. 320 kHz C. 150 kHz D. 200 kHz
Last Answer : B. 320 kHz
Description : In a FM system, the maximum deviation is 75KHz. Find bandwidth for modulating frequency i. fm=500Hz ii. fm=5KHz iii. fm=10KHz Draw conclusion for bandwidth of FM from answer.
Last Answer : Given deviation∆=75kHz i) fm=500Hz bandwidth B.W=2(∆+fm) =2(75k+500)=151kHz ii). fm=5KHz bandwidth B.W=2(∆+fm) =2(75k+5k)=160KHz iii) fm=10KHz bandwidth B.W=2(∆+fm) =2(75k+10k)=170KHz As the modulating frequency increases bandwidth also increases.
Description : Compare narrow band FM with wide-band FM w.r.t. following points. (i) Modulation index (ii) Maximum deviation (iii)Range of modulating frequency (iv)Application
Last Answer : Sr. No Parameters Narrow band FM Wide band FM 1 Modulation index Less than or slightly greater than 1 Greater than 1 2 Maximum deviation ... like police wireless, ambulance etc. Entertainment broadcasting can be used for high quality music transmission
Description : In_____, each station transmits its data in itsassignedtime slot. A) FDMA B) TDMA C) CDMA D) none of the above
Last Answer : TDMA
Description : In_____, each station is allocateda time slotduring which it can send data. Each stationtransmits its data in itsassigned time slot. A) FDMA B) TDMA C) CDMA D) none of the above
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 : In_____, the level of the voltagedetermines the valueof the bit. A) NRZ-I B) NRZ-L C) both (a) and (b) D) neither (a) nor (b)
Last Answer : NRZ-L
Description : With a single modulating tone, what is the amplitude of the sideband frequencies at 100-percent modulation?
Last Answer : One-half the amplitude of the carrier.
Description : What frequency range is used for FM radio transmission? A. Very Low Frequency : 3 kHz to 30. kHz B. Low Frequency :30 kHz to 300 kHz C. High Frequency :3 MHz to 30 MHz D. Very High Frequency : 30 MHz to 300 MHz E. None of the above
Last Answer : Very High Frequency : 30 MHz to 300 MHz
Description : In_______, the peakamplitude of one signal level is 0; the other is thesame as the amplitude of the carrier frequency. A) PSK B) OOK C) FSK D) none of the above
Last Answer : OOK
Description : In________, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remainconstant. A) ASK B) PSK C) FSK D) QAM
Last Answer : ASK
Description : The _____of a composite signal is the difference between the highest and the lowest frequencies contained in that signal. A) frequency B) period C) bandwidth D) amplitude
Last Answer : frequency
Description : In a time-domain plot, the horizontal axis is a measure of ________. A) signal amplitude B) frequency C) phase D) time
Description : Bits can be sent over guided and unguided media as analog signal by ___________ a. digital modulation b. amplitude modulation c. frequency modulation d. phase modulation
Last Answer : a. digital modulation
Description : Why can phase-modulated signals be detected by fm detectors?
Last Answer : Because of the incidental frequency shift that is caused while phase-shifting a carrier wave that is similar to fm modulation.
Last Answer : The frequency modulated (FM) radio frequency range is nearly 90 - 105 MHz.
Description : The audio signals of TV are – (1) Amplitude modulated (2) Frequency modulated (3) Unmodulated (4) Velocity modulated
Last Answer : (2) Frequency modulated Explanation: In analogue television, the sound portion of a broadcast is invariably modulated separately from the video. Most commonly, the audio and video are combined at ... visual antennas can be used. In almost all cases, standard wideband frequency modulation is used.
Description : The audio signals of TV are : (1) Amplitude modulated (2) Frequency modulated (3) Unmodulated (4) Velocity modulated
Last Answer : (2) Frequency modulated Explanation: In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with ... , the sound portion of a broadcast is invariably modulated separately from the video.
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 : 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 : The series of periodically recurrent pulses is modulated in amplitude by the corresponding instantaneous samples. A. PFM B. PWM C. PDM D. PAM
Last Answer : D. PAM
Description : In frequency modulation, amplitude of modulated wave is A. positive B. negative C. constant D. zero
Last Answer : constant
Description : In an amplitude modulated waveform, the amplitude of the sideband is
Last Answer : 1/2 carrier amplitude x modulation index
Description : Draw amplitude modulated waveform in time domain and frequency domain with proper labeling.
Last Answer : AM in Time domain AM in frequency domain
Description : The audio signals of TV are (1) Amplitude modulated (2) Frequency modulated (3) Unmodulated (4) Velocity modulated
Last Answer : Frequency modulated
Description : Ideal transmission bandwidth of FM signal is
Last Answer : Ideal transmission bandwidth of FM signal is Infinite