Description : Which components provide the regenerative feedback signal in the phase-shift oscillator?
Last Answer : Resistor-capacitor networks.
Description : What component in a blocking oscillator controls pulse width?
Last Answer : Transformer.
Description : When a transmitter uses a high-power oscillator to produce the output pulse, what switches the oscillator on and off?
Last Answer : High-voltage pulse from the modulator.
Description : The stability of transmitted signal from a simple Hartley oscillator single transmitter which is coupled to and antenna wire affected by ______. A. Chirping of oscillator B. Closer coupling between the oscillator and the antenna. C. Location of antenna D. Material of antenna
Last Answer : B. Closer coupling between the oscillator and the antenna.
Description : What type of target has a fixed phase relationship from one receiving period to the next?
Last Answer : Stationary.
Description : Adding bits to synchronize one digital signal to another is called: a. bit stuffing b. bit-synch c. SDH d. WDM
Last Answer : a. bit stuffing
Description : What transmission method uses a stable cw reference oscillator, which is locked in phase with the transmitter frequency?
Last Answer : Pulse-Doppler.
Description : Why is a high-gain transistor used in the phase-shift oscillator?
Last Answer : Because of the losses encountered in the RC networks.
Description : If the length of the fiber point defect changes with pulse duration, is the OTDR signal deviation a point defect or a region of high fiber attenuation?
Last Answer : A point defect.
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 : The major function of transistor. Q2 is A) It provides voltage gain B) It provides the feedback signal C) It isolates the oscillator from loading effects D) It provides a phase shift.
Last Answer : ) It provides a phase shift.
Description : Which of the following is not true: A) An oscillator is a circuit that converts DC to AC B) An oscillator is an amplifier that supplies its own input signal C) All oscillators generate sine waves D) In phase feedback is called positive Feedback
Last Answer : C) All oscillators generate sine waves
Description : Sound waves transmitted from a source are sometimes weak when they reach the detector. What instrument is needed to boost the weak signal?
Last Answer : An amplifier.
Description : The input to a coherent detector is DSB-SC signal plus noise. The noise at the detector output is: (1) The in-phase component (2) The quadrature-component (3) Zero (4) The envelope
Last Answer : The input to a coherent detector is DSB-SC signal plus noise. The noise at the detector output is: Zero.
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 : A coherent binary phase shift keyed BPSK transmitter operates at a bit rate of 20 Mbps with a carrier to noise ratio C/N of 8.8dB. Find Eb/No. A. 73 dB B. 62.4 dB C. 81.8 dB D. 8.8 dB
Last Answer : D. 8.8 dB
Description : ____ is a light that can be coherent ∙ a. Spontaneous emission ∙ b. Monochromatic and in-phase ∙ c. Narrow beam divergence ∙ d. Monochromatic
Last Answer : ∙ b. Monochromatic and in-phase
Description : What are three advantages of adding an ac bias voltage to the input signal instead of adding a fixed dc bias voltage?
Last Answer : a. Reproduces a stronger output signal. b. Greatly improves the SNR. c. Greatly reduces the natural tape hiss.
Description : What is the primary advantage of power-amplifier transmitters over keyed-oscillator transmitters?
Last Answer : Frequency stability.
Description : Name a disadvantage of sine-wave oscillator synchronizers.
Last Answer : It requires additional shaping circuits.
Description : What basic circuits meet the requirements of an externally synchronized master oscillator?
Last Answer : Sine-wave oscillator, single-swing blocking oscillator, and master trigger (astable) multivibrator.
Last Answer : . It requires additional shaping circuits.
Description : What type of multivibrator can be used as a radar master oscillator?
Last Answer : Free-running.
Description : What is the polarity of the first alternation of the tank circuit in an emitter-loaded npn pulsed oscillator?
Last Answer : Negative
Description : What is the identifying feature of a Colpitts oscillator?
Last Answer : Split capacitors.
Description : What is the difference between the series-fed and the shunt-fed Hartley oscillator?
Last Answer : In the series-fed Hartley oscillator, dc flows through the tank circuit.
Description : What is the main difference between the Armstrong oscillator and the Hartley oscillator?
Last Answer : Feedback coil. Armstrong uses a separate coil. Hartley uses a tapped coil.
Description : Which oscillator uses tapped capacitors for feedback?
Last Answer : Colpitts.
Description : Which oscillator uses a tapped inductor for feedback?
Last Answer : Hartley.
Description : Which oscillator uses a tickler coil for feedback?
Last Answer : Armstrong.
Description : In a heterodyne-type frequency meter, what is the difference between the oscillator frequency and the unknown frequency?
Last Answer : Beat frequency.
Description : What characteristic of a gunn oscillator is inversely proportional to the transit time of the domain across the semiconductor?
Last Answer : The frequency.
Description : Why is the tunnel diode loosely coupled to the cavity in a tunnel-diode oscillator?
Last Answer : To increase the stability.
Description : What determines the frequency of a tunnel-diode oscillator?
Last Answer : The tuned circuit or cavity frequency.
Description : In an fm transmitter, when does an oscillator generate only a steady frequency?
Last Answer : When no modulation is present.
Description : What is the function of the oscillator in a cw transmitter?
Last Answer : It generates an rf carrier at a given frequency within required limits.
Description : Name two methods of oscillator keying.
Last Answer : Plate keying and cathode keying.
Description : If If the input signals are 180 degrees out of phase with each other and a combined output is taken between the two output terminals, what will the amplitude of the combined output signal be?
Last Answer : 200 millivolts.
Description : If the two input signals to a difference amplifier are equal in amplitude but neither in phase nor 180 degrees out of phase, what will the output signal be?
Last Answer : . A different shape than the input signals but larger in amplitude.
Description : If the two input signals to a difference amplifier are equal in amplitude and 180 degrees out of phase, what will the output signal be?
Last Answer : Equal in shape and frequency to each input signal and larger in amplitude by two times than
Description : . If the two input signals of a difference amplifier are in phase and equal in amplitude, what will the output signal be?
Last Answer : No output (the signals will "cancel out").
Description : Where is the intelligence contained in a phase-modulated signal?
Last Answer : In the amount and rate of phase shift of the carrier wave.
Description : Referred to an oscillator signal “leak through” from a properly neutralized amplifier such as a master oscillator power amplifier. A. Carrier B. Stray signal C. Back wave D. Loss wave
Last Answer : C. Back wave
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 : Why should local oscillator frequency be greater than signal frequency in AM receiver? Also explain why IF has constant value?
Last Answer : Reason for LO frequency to be greater than signal frequency The local oscillator frequency (f0) is made greater than signal frequency (Fs) in radio receiver: Local oscillator frequency range is 995 ... frequency of desired signal because the IF is constant and same for all the incoming RF signal.
Description : What is the fundamental difference between the phase relationship of the harmonics of the square wave as compared to the harmonics of a peaked wave?
Last Answer : All the odd harmonics are in phase with the fundamental in the square wave. This is not true of the odd harmonics in the peaked wave.
Description : The input and output signals of a JFET amplifier have what phase relationship?
Last Answer : They are 180 degrees out of phase.
Description : What is the phase relationship between the delayed and undelayed video?
Last Answer : Opposite.