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 : What does the simplest diode detector use to reproduce the modulating frequency?
Last Answer : The modulation envelope.
Description : If a modulating wave is sampled 10 times per cycle with a 5-element binary code, how many bits of information are required to transmit the signal?
Last Answer : 28. 50.
Description : To ensure the accuracy of a transmission, what is the minimum number of times a modulating wave should be sampled in pulse modulation?
Last Answer : 2.5 times the highest modulating frequency.
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 : Sound in TV is modulating - (1) AM (2) FM (3) PCM (4) PM
Last Answer : (1) AM
Description : Transformers are used onboard ships with AC generators to _____________. A. change frequency B. increase power output to modulating frequency controllers C. decrease power output to modulating frequency ... D. permit higher voltage for electric motor operation and low voltage for lighting circuits
Last Answer : Answer: D
Description : Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? A. dc B. low C. intermediate D. high
Last Answer : D. high
Description : In radio signal emission designation, the fifth symbol means A. Details of signals B. Type of information transmitted C. Nature of multiplexing D. Nature of signal modulating the main carrier
Last Answer : C. Nature of multiplexing
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 : 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 meant by the term deviation ratio? A. The ratio of the audio modulating frequency to the center carrier frequency. B. The ratio of the maximum carrier frequency deviation to the highest ... . D. The ratio of the highest audio modulating frequency to the average audio modulating frequency.
Last Answer : B. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.
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 deviation ratio? A. The ratio of the carrier center frequency to the audio modulating frequency B. The ratio of the highest audio modulating frequency to the ... audio modulation frequency D. The ratio of the audio modulating frequency to the center carrier frequency
Last Answer : C. The ratio of the maximum carrier frequency deviation to the highest audio modulation frequency
Description : The third symbol in the designation of radio emission under the ITU rules refers to A. Type of the modulation of the main carrier B. Bandwidth C. Nature of the signals modulating the main carrier D. Type of information to be transmitted
Last Answer : D. Type of information to be transmitted
Description : The first symbol in the designation of radio emission under the ITU rules to A. Nature of signals modulating the main carrier B. Type of information to be transmitted C. Bandwidth D. Type of modulation of the main carrier
Last Answer : D. Type of modulation of the main carrier
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 : 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 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 : 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
Last Answer : In communication systems, the modulating signal is also called base band signal.
Description : The head driver circuit of a tape recorder’s FM record electronics (figure 5-4) performs what function?
Last Answer : It amplifies the frequency-modulated output from the record oscillator and sends it to the record head.
Description : The equalization and phase correction circuit in a tape recorder’s direct reproduce electronics (figure 5-2) performs what function?
Last Answer : It generates an equalization signal which corrects any frequency response problems in the input signal from the pre-amplifier circuit.
Description : The head driver circuit in a tape recorder’s direct record electronics component (figure 5-1) performs what function?
Last Answer : It takes the signal from the summing network, amplifies it, and sends it to the record head for recording.
Description : What is the primary function of an afc circuit?
Last Answer : It is used to accurately control the frequency of the oscillator.
Description : Which type of splice is used to splice a lighting fixture to a branch circuit?
Last Answer : Fixture joint.
Description : What type circuit is used to produce square or rectangular waves?
Last Answer : Multivibrator.
Description : . What characteristic of an RL circuit allows it to act as an integrator?
Last Answer : The ability of the inductor to oppose a change in current.
Description : What are the requirements for an integration circuit?
Last Answer : The time constant is long and the output is taken across the capacitor in an RC circuit.
Description : If C4 were removed from the circuit, what would happen to the output of the amplifier?
Last Answer : The output would decrease. (C4 decouples R2 preventing degenerative feedback from R2.)
Description : Can a parallel LC circuit be used as the frequency determining network for an rf amplifier?
Last Answer : Yes.
Description : If the output impedance of an amplifier circuit is decreased, what is the effect on the gain?
Last Answer : The gain decreases.
Description : What component in an amplifier circuit tends to limit the low-frequency response of the amplifier?
Last Answer : The coupling capacitor (C3).
Description : What type filter is used to allow a narrow band of frequencies to pass through a circuit and attenuate all other frequencies above or below the desired band?
Last Answer : Bandpass.
Description : What term is used to describe the frequency at which the filter circuit changes from the point of rejecting the unwanted frequencies to the point of passing the desired frequencies?
Last Answer : Frequency cutoff (fco).
Description : What is the band of frequencies called that is included between the two points at which current falls to 70 percent of its maximum value in a resonant circuit?
Last Answer : Bandwidth of the circuit
Description : When is line current minimum in a parallel-LC circuit?
Last Answer : At the resonant frequency.
Description : In a parallel-resonant circuit, what is the relationship between impedance and current?
Last Answer : Maximum impedance, minimum current.
Description : What is the term for the number of times per second that tank circuit energy is either stored in the inductor or capacitor?
Last Answer : Natural frequency or resonant frequency (f r).
Description : When the magnetic field of the inductor is completely collapsed, where is the energy of the tank circuit stored?
Last Answer : . Capacitor.
Description : When the capacitor is completely discharged, where is the energy of the tank circuit stored?
Last Answer : Inductor magnetic field
Description : In a series-RLC circuit, what is the condition of the circuit if there is high impedance, low current, and low reactance voltages
Last Answer : Nonresonant (circuit is either above or below resonance)
Description : . In an "ideal" resonant circuit, what is the relationship between impedance and current?
Last Answer : Impedance low Current high.
Description : In an a.c. circuit that contains both an inductor and a capacitor, what term is used for the difference between the individual reactances?
Last Answer : Resultant reactance.
Description : What is the output current in the common-collector circuit?
Last Answer : IE.
Description : What is the current gain in a common-base circuit called?
Last Answer : Alpha (α).
Description : What method for checking transistors is cumbersome when more than one transistor is bad in a circuit?
Last Answer : The substitution method.