Description : The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is A) 50 W B) 66 W C) 68 W D) 70 W
Last Answer : The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is 66 W
Description : If the radiated power of AM transmitter is 10 KW, the power in the carrier for modulation index of 0.6 is nearly: (1) 8.24 KW (2) 9.26 KW (3) 8.47 KW (4) 9.6 KW
Last Answer : If the radiated power of AM transmitter is 10 KW, the power in the carrier for modulation index of 0.6 is nearly: 8.47 KW.
Description : If modulation index is 0.6, maximum power efficiency (in %) of AM is about A) 60 B) 30 C) 20 D) 10
Description : In amplitude modulation scheme, the over-modulation (A) is desired phenomenon (B) helps in signal recovery (C) is undesired phenomenon (D) Envelope of AM maintains the shape of the baseband signal
Last Answer : In amplitude modulation scheme, the over-modulation is desired phenomenon
Description : An FM signal with modulation index mƒ is passed through a frequency tripler. The modulation index of the output signal will be (1) mƒ (2) 3mƒ (3) 9mƒ (4) 27mƒ
Last Answer : An FM signal with modulation index mƒ is passed through a frequency tripler. The modulation index of the output signal will be 3mƒ
Description : Amplitude modulation is used for broadcasting because (A) it is move noise immune than other modulation systems (B) compared with other systems it requires less transmitting power (C) ... receiver complexity (D) no other modulation system can provide the necessary bandwidth for high fidelity.
Last Answer : Amplitude modulation is used for broadcasting because its use avoids receiver complexity
Description : The information rate to be transmitted is 900 bits /sec, FEC is 3/4 , the symbol rate for QPSK modulation scheme is : a. 225 symbols /sec b. 450 symbols /sec c. 600 symbols /sec d. 675 symbols /sec
Description : The maximum transmission power efficiency of DSB-C Amplitude modulation is : a. 25% b. 33.33% c. 50% d. 100%
Description : The modulation system inherently most noise resistant is: (1) Frequency modulation (2) Pulse width modulation (3) Pulse code modulation (4) Phase modulation
Last Answer : The modulation system inherently most noise resistant is: Pulse code modulation.
Description : Which one of the following statements is correct? Digital modulation techniques are used in satellite communication systems since: (1) They are easier to handle (2) Large bandwidth utilization is possible (3) They have a higher spectral efficiency (4) They are less prone to interference
Last Answer : They are less prone to interference
Description : The modulation normally used with the digital data is a. PM b. AM c. SSB d. QPSK
Description : In satellite communication, frequency modulation is used because satellite channel has a. High modulation index b. Small bandwidth and negligible noise c. Large bandwidth and severe noise d. Maximum bandwidth and minimum noise
Description : A carrier signal of 600 V rms with 75% amplitude modulation is applied to 75 ohm antenna. The total side band power (in watts) is A) 4800 B) 450 C) 950 D) 1350
Last Answer : Frequency modulation gives Less noise
Description : Which cavity of a three-cavity klystron causes most of the velocity modulation?
Last Answer : The middle cavity.
Description : Amplitude Modulation (AM).
Description : An AM wave is represented by cm (t) = 6 (1+0.5 cos 12560 t) cos 22 x 105 t. Calcualte (i) amplitude and frequency of carrier. (ii) frequency of the modulating signal. (iii) modulation index. (iv) maximum and minimum amplitude of the AM wave.
Description : The following are some statement about AM (amplitude modulation) and FM (frequency modulation) (A) The circuitary for AM is more complex than that for FM. (B) The bandwidth of the signals, during AM, is twice the freqeuncy of the message ... 1) (A) and (C) (2) (B) only (3) (D) only (4) (B) and (C)
Description : The following are some statements about amplitude modulation (AM) and frequency modulation (FM) (A) The SNR (Signal to noise ratio) is better for AM as compared to FM. (B) During FM, linear amplifiers are not required because FM ... ) only (2) (B) and (D) only (3) (A) and (C) only (4) (C) only
Description : A carrier wave, c (t), given by c(t) = [12 sin (4π x 106t)] is amplitude modulated by a given sinusoidal volts message signal. The resultant (AM) carrier wave has a modulation index of 75% and a bandwidth that is 2% of the ... = [9 sin (8π x 104 t)] volt (4) on (t) = [16 sin (8π x 104 t)] volt
Description : A carrier wave c(t) = Acsin(ωct) is amplitude modulated by a message signal m(t) = Amsin(ωct) where Am = 10 v. The AM wave has a modulation index of 0.5 and side bands of frequencies 1010 kHz and 990 kHz. The value of ... (2) 5V; 2 MHz and 10 kHz (3) 20V; 1 MHz and 10 kHz (4) 20V; 2 MHz and 20 kHz
Description : The two well known types of modulation are the amplitude modulation (AM) and frequency modulation (FM). In each of these, one of the characterstics (amplitude = Ac , frequency = fc), of the carrier wave, may be made to ... fm (4) During AM, it is Ac ; and during FM, it is fc that both vary as per Am
Description : What is the full form of 'AM' regarding radio broadcasting? (1) Amplitude Movement (2) Anywhere Movement (3) Amplitude Matching (4) Amplitude Modulation
Last Answer : (4) Amplitude Modulation Explanation: AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still ... frequency. It then amplifies changes in the signal voltage to drive a loudspeaker or earphones.
Description : What modulation is normally used with digital data? A. AM B. FM C. SSB D. QPSK
Last Answer : D. QPSK
Description : What type of modulation is used on voice and video signals? A. AM B. FM C. SSB D. QPSK
Last Answer : B. FM
Description : The antenna current is doubled when the modulation index is doubled in ______ AM system. A. A5C B. A3J C. A3 D. A3H
Last Answer : B. A3J
Description : An AM transmitter is rated 100W at 100% modulation. How much power required for the carrier? A. 33.33 W B. 66.66 W C. 83.33 W D. 100 W
Last Answer : B. 66.66 W
Description : If the modulation index of an AM wave is doubled, the antenna current is also doubled, the AM system being used is A. A5C B. A3J C. A3H D. A3
Description : 100% modulation in AM means a corresponding increase in total power by: A. 25% B. 75% C. 100% D. 50%
Last Answer : D. 50%
Description : Both frequency and phase modulation utilize ________ modulation A. Phase B. AM and FM C. Digital D. Angle
Last Answer : D. Angle
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 : Three audio waves with 100,200 and 300 volts amplitude respectively, simultaneously modulate a 450 volts carrier. What is the total percent of modulation of the AM wave? A. 69 % B. 115.5 % C. 50% D. 83%
Last Answer : D. 83%
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 : Define modulation? State the desirable value of modulation index of AM.
Last Answer : Modulation: It is the process in which any of these Parameters (Amplitude, Frequency, Phase) of high frequency signal (carrier signal) are varied in accordance with low frequency signal(modulating signal) For an AM, modulation index range is 0 to 1.
Description : Give the expression for modulation index for AM and FM.
Last Answer : 1.Modulation index for AM ma=Vm / Vc Where Vm is modulating voltage Vc is the carrier voltage 2.Modulation index for FM mf=δ /fm where δ is the deviation fm is the modulating frequency
Description : Differentiate between AM and FM on the basis of: (i) Definition (ii) Bandwidth (iii) Modulation Index (iv) Application
Last Answer : Compare AM and FM on the basis of i)Definition ii)Bandwidth iii) Wave propogation iv)Number of sidebands
Description : Define modulation index in AM and give its formula.
Last Answer : In AM wave, the modulation index (m) is defined as the ratio of the amplitude of the modulating signal (Vm ) to the amplitude of carrier signal (Vc). m = Vm / Vc
Description : What is the full form of ‘AM’ regarding radio broadcasting? (1) Amplitude Movement (2) Anywhere Movement (3) Amplitude Matching (4) Amplitude Modulation
Last Answer : Amplitude Modulation
Description : i) State the significance of modulation index in AM transmission. ii) Explain the effect of modulation index on AM wave with waveforms.
Last Answer : Significance of modulation index in AM transmission It is used to determine the strength and quality of transmitted signal. If the modulation index is small, then the amount of variation in ... amplitude part of its information is lost in the process of modulation which is undesirable.
Description : Compare AM with FM with respect to following points: a) Definition. b) Modulation index. c) Bandwidth. d) Side band.
Last Answer : Parameters AM FM Definition It is the process in which the amplitude of carrier signal is varied in accordance with the instantaneous value of modulating signal keeping frequency and ... frequency deviation. Side band There are two sidebands Infinite number of sideband
Description : In amplitude modulation AM, if modulation index is more than 100% then: (1) Power of the wave increases. (2) Efficiency of transmission increases. (3) The wave gets distorted. (4) Bandwidth increases
Last Answer : In amplitude modulation AM, if modulation index is more than 100% then: The wave gets distorted.
Description : The amplifiers following the modulated stage in a low level modulation AM system be (A) linear amplifier (B) harmonic generators (C) class C power amplifiers (D) class untuned amplifiers
Last Answer : The amplifiers following the modulated stage in a low level modulation AM system be class C power amplifiers
Description : If the carrier of a 100 percent modulation modulated AM wave is suppressed, the percentage power saving will be (A) 50.55 (B) 15.55 (C) 10.66 (D) 66.66
Last Answer : If the carrier of a 100 percent modulation modulated AM wave is suppressed, the percentage power saving will be 66.66
Description : AM transmitter has a carrier power of 30 W. The percentage of modulation is 85%. Calculate the total power : (A) 5.4 W (B) 40.8 W (C) 10.8 W (D) 20.4 W
Description : A modulation which does not follow the sine wave pattern, it produces undesirable harmonics such as spurious emission A. 0% modulated B. Over-modulated C. Unmodulated D. 100% modulated
Last Answer : B. Over-modulated
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 : 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 : What, if any, noise susceptibility advantage exists for pulse-amplitude modulation over analog amplitude modulation?
Last Answer : Both are susceptible to noise and interference
Description : A modulation technique where data rates in excess of 56 kbps can be achieved over telephone circuits
Last Answer : Trellis Code Modulation
Description : Which modulation scheme would you suggest for high speed data transmission over a fading channel? A) MSK B) BPSK C) FSK D) OFDM