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 XII of the Series
551. In the phasing method of SSB generation, one sideband is cancelled due out to
- a. phase shift
- b. sharp selectivity
- c. carrier suppression
- d. phase inversion
552. It is caused by poor front-end selectivity or inadequate image frequency rejection.
- a. optimal coupling
- b. double spotting
- c. spurious pointing
- d. under coupling
553. It is a high-gain, low noise, tuned amplifier that, when used is the first active encountered by the receiver signal.
- a. mixer
- b. local oscillator
- c. RF amplifier
- d. detector
554. It is a high performance microwave receiver at the input stage. In the RF section of optimize their noise figure.
- a. high-power amplifier
- b. low noise amplifier
- c. buffer amplifier
- d. local oscillator
555. A balanced modulator used to demodulates a SSB signal is called
- a. transponder
- b. product detector
- c. converter
- d. modulator
556. Which of the following is not the other name of a balanced modulator?
- a. balanced mixer
- b. product detector
- c. product modulator
- d. none of these
557. ________ amplifiers are relatively high gain tuned amplifiers that are very similar to RF amplifiers, except that it operates over a relatively narrow, fixed frequency band.
- a. IF amplifiers
- b. low-noise amplifiers
- c. buffer amplifiers
- d. high-power amplifier
558. Type of tuned circuit where both the primary and secondary sides of the transformer are tuned tank circuits
- a. RLC tuned circuit
- b. double-tuned circuit
- c. single-tuned circuit
- d. LC tuned circuit
559. Frequency translation is done with a circuit called _______.
- a. summer
- b. multiplier
- c. filter
- d. mixer
560. Low noise RF amplifiers use what type biasing?
- a. class A
- b. class B
- c. class AB
- d. class C
561. Its purpose is to down-convert the incoming radio frequencies to intermediated frequencies.
- a. local oscillator
- b. RF amplifier
- c. detector
- d. mixer
562. It is a non-linear amplifier similar to modulator, except that the output is turned to different between the RF and local oscillator frequencies.
- a. RF amplifier
- b. local oscillator
- c. mixer
- d. detector
563. Mixing for frequency conversion is the same as
- a. rectification
- b. AM
- c. linear summing
- d. filtering
564. The most common technique used for coupling IF amplifiers
- a. resistive coupling
- b. inductive coupling
- c. capacitive coupling
- d. direct coupling
565. When the modulation index of an AM wave doubled, the antenna current is also doubled. The AM system being used is
- a. single-sideband, full carrier (H3E)
- b. vestigial sideband (C3F)
- c. single sideband, suppressed carrier (J3E)
- d. double sideband, full carrier (A3E)
566. The ability of a coil to induce a voltage within its own windings is called
- a. mutual inductance
- b. coefficient coupling
- c. self- inductance
- d. inductance
567. If the carrier of a 100 percent modulated AM wave is suppressed the percentage power saving will be
- a. 50
- b. 150
- c. 100
- d. 66.66
568. The ability of one coil to induce a voltage in another coil is called _________.
- a. coefficient coupling
- b. mutual inductance
- c. inductance
- d. self-inductance
569. Which of the following cam be used as a mixer?
- a. balanced modulator
- b. FET
- c. diode modulator
- d. all of the above
570. It is the ratio of the secondary flux to primary flux
- a. Q factor
- b. coefficient coupling
- c. self-inductance
- d. coefficient of modulation
571. Type of coupling where the secondary voltage is relatively low and the bandwidth is narrow.
- a. tight coupling
- b. optimum coupling
- c. loose coupling
- d. critical coupling
572. An AM signal, transmitted information is contained within the
- a. carrier
- b. modulating signal
- c. sidebands
- d. envelope
573. Type of coupling which has high gain and a broad bandwidth
- a. optimum coupling
- b. tight coupling
- c. double coupling
- d. loose coupling
574. It is the point where the reflected resistance is equal to primary resistance and the Q of the primary tank circuit is halved and the bandwidth doubled.
- a. critical coupling
- b. tight coupling
- c. loose coupling
- d. optimum coupling
575. The desired output from a mixer is usually selected with a
- a. phase-shift circuit
- b. crystal filter
- c. resonant circuit
- d. transformer
576. It is caused by the reactive element of the reflected impedance being significant enough to change the resonant frequency of the primary tuned circuit.
- a. optimum coupling
- b. critical coupling
- c. double peaking
- d. flux linkage
577. IF transformers come as specially designed tuned circuits in groundable metal packages called _______.
- a. IF cans
- b. IF container
- c. IF strip
- d. IF tetrapack
578. The AM detector is sometimes called _______.
- a. first detector
- b. third detector
- c. second detector
- d. fourth detector
579. The mixer is sometimes called _________.
- a. first detector
- b. third detector
- c. second detector
- d. fourth detector
580. The two inputs to a mixer are the signal to be translated and a signal from
- a. modulator
- b. filter
- c. antenna
- d. local oscillator
581. AM demodulator is commonly called _________.
- a. phase detector
- b. peak detector
- c. frequency detector
- d. transistor detector
582. A type of detector that detects the shape of the input envelope
- a. peak detector
- b. phase detector
- c. diode detector
- d. shape detector
583. The ratio of the peak modulating signal voltage to the peak carrier voltage is referred to as
- a. voltage ratio
- b. decibels
- c. modulation index
- d. mix factor
584. A circuit that automatically increases the receiver gain for weak RF input levels and automatically decreases the receiver gain when a strong RF signal is received.
- a. automatic volume control
- b. automatic frequency control
- c. automatic gain control
- d. automatic phase control
585. Which is not a type of AGC?
- a. simple AGC
- b. forward AGC
- c. delayed AGC
- d. complex AGC
586. The value Vmax and Vmin as read from AM wave on an oscilloscope are 3.0 and 2.8. The percentage of modulation is
- a. 10 percent
- b. 41.4 percent
- c. 80.6 percent
- d. 93.3 percent
587. Amplitude modulation is used for broadcasting because
- a. it is more noise immune than other modulation systems
- b. compared to other systems it requires less transmitting power
- c. its use avoids receiver complexity
- d. no other modulation system can provide the necessary bandwidth for high fidelity
588. Type of AGC that prevents the AGC feedback voltage from reaching the RF or IF amplifiers until the RF level exceeds a predetermined magnitude.
- a. forward AGC
- b. delayed AGC
- c. complex AGC
- d. simple AGC
589. A circuit with a purpose to quiet a receiver in the absence of a received signal.
- a. automatic gain control
- b. automatic frequency control
- c. squelch circuit
- d. automatic volume control
590. A section of a audio stage of a receiver that removes sporadic, high amplitude noise transients of short duration, such as impulse noise.
- a. squelch circuit
- b. clampers
- c. clippers
- d. peak detector
591. A circuit that detects the occurrence of a high-amplitude, short duration noise spike then mutes the receiver by shutting off a portion of the receiver of the duration of the pulse.
- a. squelch circuit
- b. limiter
- c. clamper
- d. blanking circuit
592. The opposite modulation is
- a. reverse modulation
- b. downward modulation
- c. unmodulation
- d. demodulation
593. For good image-frequency rejection, what is the desired value of the intermediate frequency?
- a. relatively low IF
- b. very low IF
- c. relatively high IF
- d. very high IF
594. With high-gain selective amplifiers that are stable and easily neutralized. what is the desired value of intermediate frequency?
- a. low IF
- b. medium IF
- c. high IF
- d. very high IF
595. It is defined as the ratio of the demodulated signal level at the output receiver to the RF signal level at the input to the receiver.
- a. received signal level
- b. figure of merit
- c. effective radiated power
- d. net receiver gain
596. It is the process of modifying the characteristic of one signal in accordance with some characteristic of another signal.
- a. multiplexing
- b. mixing
- c. modulation
- d. summing
597. The imaginary line on the carrier waveform of the amplitude modulated signal is called __________.
- a. sidebands
- b. envelope
- c. spurious emission
- d. information
598. Indicate the false statement regarding the advantages of the phase cancellation method of obtaining SSB over the filter method is false:
- a. more channel space available
- b. transmitter circuits must be stable, giving better spectrum
- c. the signal is more noise resistant
- d. much less power is required for the same signal strength
599. Indicate which one of the following advantages of the phase cancellation method of obtaining SSB over the filter method is false:
- a. switching from one sideband to the other simpler
- b. it is possible to generated SSB at any frequency
- c. SSB with lower audio frequencies present can be generated.
- d. There are more balanced modulators, therefore the carrier is suppressed better
600. The most commonly used filters is SSB generation are
- a. mechanical
- b. RC
- c. LC
- d. low-pass
Post a Comment