Online Questions and Answers Topic Outline
- MCQs in Amplitude Modulation
- MCQs in Phase Modulation
- MCQs in Sound Pressure Level
- MCQs in Frequency Modulation
- MCQs in Pulse Modulation
MCQs in Modulation Series
Following is the list of multiple choice questions in this brand new series:
Continue Practice Exam Test Questions Part V of the Series
201. What is emission F3F?
- A. AM
- B. Facsimile
- C. Television
- D. RTTY
202. What type of emission is produced when a frequency modulated transmitter is modulated by a facsimile signal?
- A. F3C
- B. A3C
- C. F3F
- D. A3F
203. Two AM transmitting antennas are close together. As a result the two modulated signals are mixed in the final RF stage of both transmitters. What is the resultant effect on other station?
- A. Harmonic interference
- B. Intermodulation interference
- C. Spurious interference
- D. Crossmodulation interference
204. The term used to refer to the reduction of receiver gain caused by the signal of a nearby station transmitter in the same frequency band?
- A. Quieting
- B. Cross-modulation interference
- C. Squelch gain rollback
- D. Desensitizing
205. What is the bandwidth occupied by the carrier, both sidebands and harmonics?
- A. Authorized bandwidth
- B. Bandwidth of emission and occupied bandwidth
- C. Operating bandwidth
- D. All of these
206. A class-C RF amplifier is collector amplitude modulated and its average dc level collector current does not change. This means
- A. A normal condition
- B. Excessive drive to the base
- C. Insufficient drive to the base
- D. Insufficient audio modulation
207. What determines the percentage modulation of an FM transmitter?
- A. Amplitude of the carrier
- B. Modulating frequency
- C. Carrier frequency
- D. Amplitude of the modulating signal
208. Deviation ratio of an FM transmitter is the ratio of the
- A. Maximum frequency swing to the highest modulating frequency
- B. Operating frequency of the assigned frequency
- C. Frequency swing to the modulating frequency
- D. Highest modulating frequency to the minimum frequency
209. The main purpose of the beat frequency oscillator (BFO) is to generate
- A. A 1 kHz not for Morse reception
- B. Aid in the reception of weak voice-modulated signals
- C. An output, whose frequency differs from the IF by 1 kHz
- D. A signal, whose frequency is the same as intermediate frequency
210. Normally, a linear class BRF power amplifier operates with a bias approximately equal to
- A. Twice cut-off
- B. Ten times cut-off value
- C. 50% of cut-off value
- D. Projected cut-off
211. The purpose why an RF amplifier is operated under linear class-B conditions (as opposed to class-C) is to
- A. Generate only even harmonics
- B. Generate only odd harmonics
- C. Increase the efficiency
- D. Amplify of an AM signal
212. The term used to refer to the condition where the signal from a very strong station are superimposed on other signal being received.
- A. Cross-modulation interference
- B. Intermodulation distortion
- C. Receiver quieting
- D. Capture effect
213. _________ is the amplitude of the maximum negative excursion of a signal as viewed on an oscilloscope.
- A. Peak-to-peak voltage
- B. Inverse peak positive voltage
- C. RMS voltage
- D. Peak negative voltage
214. The type of emission that suffer most from selective fading.
- A. CW and SSB
- B. SSB and TV
- C. FM and double sideband AM
- D. SSTV and CW
215. In an FM-phone signal, ________ is the ratio between the actual frequency deviation to the maximum frequency deviation.
- A. FM compressibility
- B. Modulating index
- C. Percentage of modulation
- D. Quieting index
216. _______ is used to refer to the reception blockage of one FM-phone signal by another FM-phone signal.
- A. Capture effect
- B. Desensitization
- C. Cross-modulation interference
- D. Frequency discrimination
217. A receiver selectivity of 10 kHz in the IF circuitry is optimum for what type of signals?
- A. SSB voice
- B. Facsimile
- C. FM
- D. Double-sideband AM
218. If the envelope of modulation is constant in amplitude this means
- A. Zero beat
- B. Under-modulation
- C. Zero-modulation
- D. Over-modulation
219. What is the approximate bandwidth of an FM with a modulation factor of 12.5 and a modulating frequency of 10 kHz?
- A. 20 kHz
- B. 270 kHz
- C. 250 kHz
- D. 45 kHz
220. Amplitude modulation is the same as
- A. Linear mixing
- B. Analog multiplication
- C. Signal summation
- D. Multiplexing
221. The negative half of the AM wave is supplied by a/an _______ on a diode modulator.
- A.
- B. Transformer
- C. Capacitor
- D. Inductor
222. One of the following can produce AM.
- A. Having the carrier vary a resistance
- B. Having the modulating signal vary a capacitance
- C. Varying the carrier frequency
- D. Varying the gain of an amplifier
223. Amplitude modulators that vary the carrier amplitude with the modulating signal by passing it through an attenuator network is the principle of
- A. Rectification
- B. Amplification
- C. Variable resistance
- D. Absorption
224. Which component is used to produce AM at very high frequencies?
- A. Varactor diode
- B. Thermistor
- C. Cavity resonator
- D. PIN diode
225. A collector modulator has a supply voltage of 48 V. What is the peak-to-peak amplitude of the modulating signal for 100 percent modulation?
- A. 24 V
- B. 48 V
- C. 96 V
- D. 120 V
226. What circuit recovers the original modulating information from an AM signal?
- A. Modulator
- B. Demodulator
- C. Mixer
- D. Crystal set
227. What is the most commonly used amplitude demodulator?
- A. Envelope detector
- B. Balanced modulator
- C. Mixer
- D. Crystal set
228. What circuit generates the upper and lower sidebands and suppresses the carrier?
- A. Amplitude modulator
- B. Diode detector
- C. Class C amplifier
- D. Balanced modulator
229. _________ is a widely used balanced modulator.
- A. Diode bridge circuit
- B. Full-wave bridge rectifier
- C. Lattice modulator
- D. Balanced bridge modulator
230. In a diode ring modulator, the diodes act like
- A. Variable resistors
- B. Switches
- C. Rectifiers
- D. Variable capacitors
231. The output of a balanced modulator is
- A. AM
- B. FM
- C. SSB
- D. DSB
232. The principal circuit in the popular 1496/1596 IC balanced modulator is a
- A. Differential amplifier
- B. Rectifier
- C. Bridge
- D. Constant current source
233. The most commonly used filter in SSB generators uses
- A. LC networks
- B. Mechanical resonators
- C. Crystals
- D. RC networks and op amps
234. In the phasing method of SSB generation, one sideband is canceled out due to
- A. Phase shifting
- B. Sharp selectivity
- C. Carrier suppression
- D. Phase inversion
235. A balanced modulator used to demodulate a SSB signal is call a/an
- A. Transponder
- B. Product detector
- C. Converter
- D. Remodulator
236. Frequency translation is done with a circuit called a
- A. Summer
- B. Multiplier
- C. Divider
- D. Mixer
237. Mixing for frequency conversion is the same as
- A. Rectification
- B. AM
- C. Linear summing
- D. Filtering
238. Which of the following is not a major advantage of FM over AM?
- A. Greater efficiency
- B. Noise immunity
- C. Capture effect
- D. Lower complexity and cost
239. The primary disadvantage of FM is its
- A. Higher cost and complexity
- B. Excessive use of spectrum space
- C. Noise susceptibility
- D. Lower efficiency
240. Noise is primarily
- A. High-frequency spikes
- B. Lowe-frequency variations
- C. Random level shifts
- D. Random frequency variations
241. The receiver circuit that rids FM of noise is the
- A. Modulator
- B. Demodulator
- C. Limiter
- D. Low-pass filter
242. The AM signals generated at a low level may only be amplified by what type of amplifier?
- A. Class A
- B. Class B
- C. Class C
- D. All of the above
243. SSB means
- A. Single sideband with suppressed carrier
- B. Single sideband with carrier
- C. Double sideband with no carrier
- D. Single sideband with reduced carrier
244. A circuit used to select the desired output from a mixer
- A. Transformer
- B. Resonant circuit
- C. Filter
- D. Phase-shift circuit
245. What is the output of a balanced modulator?
- A. AM
- B. DSB
- C. SSB
- D. ISB
246. The acronym SSSC refer to
- A. Suppressed sideband, single carrier
- B. Suppressed sideband, suppressed carrier
- C. Single sideband, suppressed carrier
- D. Single sideband, single carrier
247. Which process occurs in the receiver?
- A. Demodulation
- B. Reception
- C. Modulation
- D. Recreation
248. What is usually used to demodulate SSB or CW signal?
- A. PLL
- B. BFO
- C. Ratio detector
- D. All of these
249. Which of the following is the most widely used amplitude modulator
- A. Diode detector
- B. PLL circuit
- C. VCO
- D. All of these
250. Which of the following is the most widely used balanced modulator
- A. Full-wave bridge circuit
- B. Balanced bridge modulator
- C. Lattice modulator
- D. None of these
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