Description : Quantizing noise occurs in A. PCM B. PLM C. PDM D. PAM
Last Answer : A. PCM
Description : How can a peak detector for pam be modified to detect pdm?
Last Answer : By making the time constant for charging the capacitor at least 10 times the maximum received pulse width.
Description : Compare PAM, PWM, and PPM on the basis of i. Variable characteristics ii. Bandwidth iii. Information contained in iv. Transmitted power
Last Answer : Compare PAM, PWM, and PPM on the basis of i. Variable characteristics ii. Bandwidth iii. Information contained in iv. Transmitted power
Description : Define PAM, PWM, and PPM. Draw waveforms.
Last Answer : Pulse amplitude modulation is defined as a process of varying the amplitude of the carrier pulse in accordance to the modulating signal variations. Pulse width modulation is defined as a ... of varying the position of the carrier pulse, in accordance to the modulating signal variations.
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 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 : 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 : 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 : Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk
Last Answer : C. Impulse noise
Last Answer : A. Quantizing noise
Description : Modulation means A. Varying of information B. Utilization of a single transmission channel to carry multiple signals C. Varying of some parameters of a carrier such as its amplitude to transmit information D. Transmit pulses in DC form on a copper wire
Last Answer : C. Varying of some parameters of a carrier such as its amplitude to transmit information
Description : How would one squeeze more channels of communication into TDM frames of standard length? A. Shorten the time delay for each channel B. Raise the amplitude C. Add modulators D. Remove the synchronizing pulses
Last Answer : A. Shorten the time delay for each channel
Description : Proctor and Gamble periodically sends out coupons and free samples of products. This illustrates P & G's use of which one of the following elements of the promotion mix? A)Advertising B)Personal selling C)Sales promotion D)Publicity
Last Answer : C)Sales promotion
Description : ECE Board Exam March 1996 Which of the following pulse modulation systems is analog? A. Delta B. Differential PCM C. PWM D. PCM
Last Answer : C. PWM
Description : What is the advantage of PTM over PAM? A. All of these B. Low sampling rate is required C. Much better noise immunity D. Simpler to generate
Last Answer : C. Much better noise immunity
Description : This is referred to a product of simultaneous frequency and amplitude modulation or a carrier frequency variation which produces unwanted distortion. A. Absorption modulation B. Simultaneous modulation C. Dynamic instability D. Series modulation
Last Answer : C. Dynamic instability
Description : What is the instantaneous amplitude of a sine wave?
Last Answer : The value at any given point on the sine wave.
Description : Define the terms related to a.c. supply with waveform : i) Instantaneous value ii) Time period iii) Amplitude iv) Phase difference.
Last Answer : i) Instantaneous value: The instantaneous value is the value of an alternating quantity (it may ac voltage or ac current or ac power) at a particular instant of time in the cycle . OR ... difference: Phase difference is the difference in phase angle between two sinusoids or phasors.
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 : In FM, frequency of modulated wave varies with A. amplitude B. time C. wavelength D. energy
Last Answer : time
Description : In frequency modulation, amplitude of modulated wave is A. positive B. negative C. constant D. zero
Last Answer : constant
Description : Amplitude of modulated wave is in phase with A. output B. system C. frequency D. signal
Last Answer : signal
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 : 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, thecarrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal. A) AM B) PM C) FM D) none of the above
Last Answer : AM
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 : 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 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 : Which circuit detects frequency modulated signal? A. Modulator B. Discriminator C. Demodulator D. Modem
Last Answer : B. Discriminator
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 : 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 : A transmitter supplies 8 kW to the antenna when it is unmodulated, determine the total radiated power when modulated at 90%. A. 5 kW B. 20 kW C. 15 kW D. 8.36 kW
Last Answer : D. 8.36 kW
Description : What is emission F3F? A. Facsimile B. Modulated CW C. RTTY D. Television
Last Answer : D. Television
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
Description : What do you call the energy that was not radiated into space or completely transmitted? A. Incident waves B. Captured waves C. Standing waves D. Modulated waves
Last Answer : C. Standing waves
Description : Energy that has neither been radiated into space nor completely transmitted. A. Captured waves B. Incident waves C. Standing waves D. Modulated waves
Description : The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the ... . Reference audio output B. None of these C. Audio frequency response D. Residual noise level
Last Answer : D. Residual noise level
Description : ECE Board Exam March 1996 What is the purpose of a beat frequency oscillator (BFO)? A. Aid in the reception of weak voice-modulated signals B. Generates a signal, whose frequency is the ... reception D. Generates an output, whose frequency differs from that of the intermediate frequency by 1 kHz
Last Answer : C. Generates a 1kHz note for Morse code reception
Description : A lateral incisor labial to the arch needs to be restored in normal alignment with PFM retraction. How will the tooth appear: A. Too wide B. Too short C. To narrow D. To long
Last Answer : C. To narrow
Description : A component that samples the microwave signal travelling in one direction down to the transmission line A. Isolator B. Combiner C. Directional coupler D. Attenuator
Last Answer : C. Directional coupler
Description : The first laser emitted a. Pulses of 694 nm red light b. A continuous red beam c. Pulses of white light from a helical flashlamp d. Spontaneous emission
Last Answer : a. Pulses of 694 nm red light
Description : What is the non-continuous noise of irregular pulses or spikes of duration with high amplitudes? A. Wander B. Jitter C. Hits D. Singing
Last Answer : B. Jitter
Description : Modulation in which no signal is present between pulses A. Pulse modulation B. QAM C. PSK D. FSK
Last Answer : A. Pulse modulation