Ham Radio 2000/Ham Radio 2000.iso/ham2000/exams/adv21/adv7.dat

Text File | 1993-03-09 | 16KB | 469 lines

342G-5.10  C 7-39  It is stable in frequency
Why is the Colpitts oscillator circuit commonly used in a VFO?
A. The frequency is a linear function of the load impedance
B. It can be used with or without crystal lock-in
C. It is stable
D. It has high output power
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343G-6.1   D 7-15  Information added to RF|or other carrier
What is meant by the term modulation?
A. The squelching of a signal until a critical signal-to-
   noise ratio is reached
B. Carrier rejection through phase nulling
C. A linear amplification mode
D. A mixing process whereby information is imposed upon a
   carrier
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344G-6.2   B 7-21  Oscillator frequency is varied|by a reactance modulator
How is an F3E FM-phone emission produced?
A. With a balanced modulator on the audio amplifier
B. With a reactance modulator on the oscillator
C. With a reactance modulator on the final amplifier
D. With a balanced modulator on the oscillator
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345G-6.3   C 7-21  Acts as a variable L or|C to produce FM signals
What is a reactance modulator?
A. A circuit that acts as a variable resistance or capacitance
   to produce FM signals
B. A circuit that acts as a variable resistance or capacitance
   to produce AM signals
C. A circuit that acts as a variable inductance or capacitance
   to produce FM signals
D. A circuit that acts as a variable inductance or capacitance
   to produce AM signals
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346G-6.4   B 7-16  Produces DSB suppressed carrier
What is a balanced modulator?
A. An FM modulator that produces a balanced deviation
B. A modulator that produces a double sideband, suppressed
   carrier signal
C. A modulator that produces a single sideband, suppressed
   carrier signal
D. A modulator that produces a full carrier signal
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347G-6.5   D 7-16  Use a filter to select|the desired sideband
How can a single-sideband phone signal be generated?
A. By driving a product detector with a DSB signal
B. By using a reactance modulator followed by a mixer
C. By using a loop modulator followed by a mixer
D. By using a balanced modulator followed by a filter
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348G-6.6   D 7-15  Plate modulation
How can a double-sideband phone signal be generated?
A. By feeding a phase modulated signal into a low pass
   filter
B. By using a balanced modulator followed by a filter
C. By detuning a Hartley oscillator
D. By modulating the plate voltage of a class C amplifier
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349G-7.1   A 7-31  RF out/DC in
How is the efficiency of a power amplifier determined?
                  RF power out
A.  Efficiency =  ────────────  X 100%
                  DC power in
                  RF power in
B.  Efficiency =  ────────────  X 100%
                  RF power out
                  RF power in
C.  Efficiency =  ────────────  X 100%
                  DC power in
                  DC power in
D.  Efficiency =  ────────────  X 100%
                  RF power in
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350G-7.2   B 7-33  Rl = Vp/K*Ip,  K=2 (class C)|Rl = 1500/(2*.5),  Rl = 1500
For reasonably efficient operation of a vacuum-tube Class C
amplifier, what should the plate-load resistance be with 1500-
volts at the plate and 500-milliamperes plate current?
A. 2000 ohms
B. 1500 ohms
C. 4800 ohms
D. 480 ohms
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351G-7.3   C 7-33  Rl = Vp/K*Ip,   K=1.57 (class B)|Rl = 800/(1.57*.075),  Rl = 6794
For reasonably efficient operation of a vacuum-tube Class B
amplifier, what should the plate-load resistance be with 800-
volts at the plate and 75-milliamperes plate current?
A. 679.4 ohms
B. 60 ohms
C. 6794 ohms
D. 10,667 ohms
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352G-7.4   A 7-33  Rl = Vp/K*Ip,   K=1.30 (class A)|Rl = 250/(1.30*.025),  Rl = 7692
For reasonably efficient operation of a vacuum-tube Class A
amplifier, what should the plate-load resistance be with 250-
volts at the plate and 25-milliamperes plate current?
A. 7692 ohms
B. 3250 ohms
C. 325 ohms
D. 769.2 ohms
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353G-7.5   B 7-33  Rl = Vcc*Vcc/2*Po,  Rl = 144/10
For reasonably efficient operation of a transistor
amplifier, what should the load resistance be with
12-volts at the collector and 5 watts power output?
 A. 100.3 ohms
 B. 14.4 ohms
 C. 10.3 ohms
 D. 144 ohms
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354G-7.6   B 7-26  LC oscillations
What is the flywheel effect?
A. The continued motion of a radio wave through space when the
   transmitter is turned off
B. The back and forth oscillation of electrons in an LC circuit
C. The use of a capacitor in a power supply to filter rectified AC
D. The transmission of a radio signal to a distant station by
   several hops through the ionosphere
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355G-7.7   C 7-35  Out-of-phase feedback.  Feedback|means from output to input.
How can a power amplifier be neutralized?
A. By increasing the grid drive
B. By feeding back an in-phase component of the
   output to the input
C. By feeding back an out-of-phase component of
   the output to the input
D. By feeding back an out-of-phase component of
   the input to the output
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356G-7.8   B 7-26  Twelve letters in Tank Circuit Q
What order of Q is required by a tank-circuit sufficient
to reduce harmonics to an acceptable level?
A. Approximately 120
B. Approximately 12
C. Approximately 1200
D. Approximately 1.2
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357G-7.9   C 7-36  Neutralization
How can parasitic oscillations be eliminated from a
power amplifier?
A. By tuning for maximum SWR
B. By tuning for maximum power output
C. By neutralization
D. By tuning the output
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358G-7.10  D 7-37  Dip plate with tuning cap
What is the procedure for tuning a power amplifier having an
output pi-network?
A. Adjust the loading capacitor to maximum capacitance and
   then dip the plate current with the tuning capacitor
B. Alternately increase the plate current with the tuning
   capacitor and dip the plate current with the loading capacitor
C. Adjust the tuning capacitor to maximum capacitance and then
   dip the plate current with the loading capacitor
D. Alternately increase the plate current with the loading
   capacitor and dip the plate current with the tuning capacitor
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359G-8.1   B 7-10  Recovering modulation|sometimes intelligent
What is the process of detection?
A. The process of masking out the intelligence on a received
   carrier to make an S-meter operational
B. The recovery of intelligence from the modulated RF signal
C. The modulation of a carrier
D. The mixing of noise with the received signal
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360G-8.2   A 7-13  Rectification
What is the principle of detection in a diode detector?
A. Rectification and filtering of RF
B. Breakdown of the Zener voltage
C. Mixing with noise in the transition region of the diode
D. The change of reactance in the diode with respect to
   frequency
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361G-8.3   C 7-14  Mixes signal with local carrier
What is a product detector?
A. A detector that provides local oscillations for input
   to the mixer
B. A detector that amplifies and narrows the band-pass
   frequencies
C. A detector that uses a mixing process with a locally
   generated carrier
D. A detector used to detect cross-modulation products
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362G-8.4   B 7-14  Discriminator
How are FM-phone signals detected?
A. By a balanced modulator
B. By a frequency discriminator
C. By a product detector
D. By a phase splitter
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363G-8.5   A 7-14  FM detecter
What is a frequency discriminator?
A. A circuit for detecting FM signals
B. A circuit for filtering two closely adjacent signals
C. An automatic bandswitching circuit
D. An FM generator
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364G-8.6   D 7-10  Sum and difference
What is the mixing process?
A. The elimination of noise in a wideband receiver
   by phase  comparison
B. The elimination of noise in a wideband receiver
   by phase differentiation
C. Distortion caused by auroral propagation
D. The combination of two signals to produce sum and
   difference frequencies
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365G-8.7   C 7-10  Sum and difference plus|input frequencies
What are the principal frequencies which appear at the
output of a mixer circuit?
A. Two and four times the original frequency
B. The sum, difference and square root of the input
   frequencies
C. The original frequencies and the sum and difference
   frequencies
D. 1.414 and 0.707 times the input frequency
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366G-8.8   B 7-11  Selectivity and tuning
What are the advantages of the frequency-conversion process?
A. Automatic squelching and increased selectivity
B. Increased selectivity and optimal tuned-circuit design
C. Automatic soft limiting and automatic squelching
D. Automatic detection in the RF amplifier and increased
   selectivity
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367G-8.9   A 7-12  Spurious products called distortion
What occurs in a receiver when an excessive amount of
signal energy reaches the mixer circuit?
A. Spurious mixer products are generated
B. Mixer blanking occurs
C. Automatic limiting occurs
D. A beat frequency is generated
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368G-9.1   B 7-31  Enough to mask(overcome) noise
How much gain should be used in the RF amplifier stage
of a receiver?
A. As much gain as possible short of self oscillation
B. Sufficient gain to allow weak signals to overcome
   noise generated in the first mixer stage
C. Sufficient gain to keep weak signals below the noise
   of the first mixer stage
D. It depends on the amplification factor of the first
   IF stage
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369G-9.2   C 7-31  Prevent distortion, ie.|spurious mixer products
Why should the RF amplifier stage of a receiver only
have sufficient gain to allow weak signals to overcome
noise generated in the first mixer stage?
A. To prevent the sum and difference frequencies from
   being generated
B. To prevent bleed-through of the desired signal
C. To prevent the generation of spurious mixer products
D. To prevent bleed-through of the local oscillator
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370G-9.3   C 7-31  Improve noise figure
What is the primary purpose of an RF amplifier in a
receiver?
A. To provide most of the receiver gain
B. To vary the receiver image rejection by utilizing
   the AGC
C. To improve the receiver's noise figure
D. To develop the AGC voltage
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371G-9.4   A 7-33  Intermediate frequency amplifiers|usually have fixed tuned filters
What is an i-f amplifier stage?
A. A fixed-tuned pass-band amplifier
B. A receiver demodulator
C. A receiver filter
D. A buffer oscillator
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372G-9.5   C 7-35  Selectivity
What factors should be considered when selecting an
intermediate frequency?
A. Cross-modulation distortion and interference
B. Interference to other services
C. Image rejection and selectivity
D. Noise figure and distortion
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373G-9.6   D 7-33  Selectivity
What is the primary purpose of the first i-f amplifier
stage in a receiver?
A. Noise figure performance
B. Tune out cross-modulation distortion
C. Dynamic response
D. Selectivity
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374G-9.7   B 7-35  Gain
What is the primary purpose of the final i-f amplifier
stage in a receiver?
A. Dynamic response
B. Gain
C. Noise figure performance
D. Bypass undesired signals
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375G-10.1  C 7-28  Common emitter amplifier
What type of circuit is shown in Figure 4AG-10?
A. Switching voltage regulator
B. Linear voltage regulator
C. Common emitter amplifier
D. Emitter follower amplifier
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376G-10.2  B 7-29  Bias that is fixed(set) by R1 & R2
In Figure 4AG-10, what is the purpose of R1 and R2?
A. Load resistors
B. Fixed bias
C. Self bias
D. Feedback
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377G-10.3  D 7-29  Coupling
In Figure 4AG-10, what is the purpose of C1?
A. Decoupling
B. Output coupling
C. Self bias
D. Input coupling
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378G-10.4  D 7-29  Emitter bypass
In Figure 4AG-10, what is the purpose of C3?
A. AC feedback
B. Input coupling
C. Power supply decoupling
D. Emitter bypass
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379G-10.5  D 7-29  Bias from the active device(self)
In Figure 4AG-10, what is the purpose of R3?
A. Fixed bias
B. Emitter bypass
C. Output load resistor
D. Self bias
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380G-11.1  B 7-30  Common collecter
What type of circuit is shown in Figure 4AG-11?
A. High-gain amplifier
B. Common-collector amplifier
C. Linear voltage regulator
D. Grounded-emitter amplifier
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381G-11.2  A 7-30  Emitter load
In Figure 4AG-11, what is the purpose of R?
A. Emitter load
B. Fixed bias
C. Collector load
D. Voltage regulation
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382G-11.3  D 7-30  Collector bypass
In Figure 4AG-11, what is the purpose of C1?
A. Input coupling
B. Output coupling
C. Emitter bypass
D. Collector bypass
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383G-11.4  A 7-30  Coupling
In Figure 4AG-11, what is the purpose of C2?
A. Output coupling
B. Emitter bypass
C. Input coupling
D. Hum filtering
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384G-12.1  C 7-5   Linear voltage regulator
What type of circuit is shown in Figure 4AG-12?
A. Switching voltage regulator
B. Grounded emitter amplifier
C. Linear voltage regulator
D. Emitter follower
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385G-12.2  B 7-5   Voltage reference
What is the purpose of D1 in the circuit shown in Figure 4AG-12?
A. Line voltage stabilization
B. Voltage reference
C. Peak clipping
D. Hum filtering
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386G-12.3  C 7-5   Handles load current
What is the purpose of Q1 in the circuit shown in Figure 4AG-12?
A. It increases the output ripple
B. It provides a constant load for the voltage source
C. It increases the current handling capability
D. It provides D1 with current
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387G-12.4  D 7-5   Filtering supply voltage
What is the purpose of C1 in the circuit shown in Figure 4AG-12?
A. It resonates at the ripple frequency
B. It provides fixed bias for Q1
C. It decouples the output
D. It filters the supply voltage
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388G-12.5  A 7-5   Filtering for D1 to remove hum
What is the purpose of C2 in the circuit shown in Figure 4AG-12?
A. It bypasses hum around D1
B. It is a brute force filter for the output
C. To self resonate at the hum frequency
D. To provide fixed DC bias for Q1
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389G-12.6  A 7-5   Prevents oscillation
What is the purpose of C3 in the circuit shown in Figure 4AG-12?
A. It prevents self-oscillation
B. It provides brute force filtering of the output
C. It provides fixed bias for Q1
D. It clips the peaks of the ripple
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390G-12.7  C 7-5   Diode current
What is the purpose of R1 in the circuit shown in Figure 4AG-12?
A. It provides a constant load to the voltage source
B. It couples hum to D1
C. It supplies current to D1
D. It bypasses hum around D1
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391G-12.8  D 7-5   Minimum load
What is the purpose of R2 in the circuit shown in Figure 4AG-12?
A. It provides fixed bias for Q1
B. It provides fixed bias for D1
C. It decouples hum from D1
D. It provides a constant minimum load for Q1
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392G-13.1  C 5-16  C = 1/40*L*F2,  Pick F=3.75 MHz|C = 1/(40*20E-6*(3.75E6)2)|C = 89 pF
What value capacitor would be required to tune a 20-microhenry
inductor to resonate in the 80-meter wavelength band?
A. 150 picofarads
B. 200 picofarads
C. 100 picofarads
D. 100 microfarads
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393G-13.2  D 5-16  L = 1/40*C*F*F,  Pick F = 7.25 MHz|L = 1/(40*100E-12*7.25E6*7.25E6)  |L = 4.76 µH
What value inductor would be required to tune a 100-picofarad
capacitor to resonate in the 40-meter wavelength band?
A. 200 microhenrys
B. 150 microhenrys
C. 5 millihenrys
D. 5 microhenrys
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394G-13.3  A 5-16  C = 1/40*L*F2,  Pick F = 14.2 MHz|C = 1/(40*2E-6*(14.2E6)2)|C = 62 pF
What value capacitor would be required to tune a 2-microhenry
inductor to resonate in the 20-meter wavelength band?
A. 64 picofarads
B. 6 picofarads
C. 12 picofarads
D. 88 microfarads
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395G-13.4  C 5-16  L = 1/40*C*F2, Pick F = 21.1 MHz|L = 1/(40*15E-12*21.1E6*21.1E6)  |L = 3.7 µH
What value inductor would be required to tune a 15-picofarad
capacitor to resonate in the 15-meter wavelength band?
A. 2 microhenrys
B. 30 microhenrys
C. 4 microhenrys
D. 15 microhenrys
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396G-13.5  A 5-16  C = 1/40*L*F2,  Pick F = 1.8 kHz|C = 1/(40*100E-6*1.8E6*1.8E6)|C = 77 pF
What value capacitor would be required to tune a 100-microhenry
inductor to resonate in the 160-meter wavelength band?
A. 78 picofarads
B. 25 picofarads
C. 405 picofarads
D. 40.5 microfarads
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397H-1.1   A 8-2   Third digit C for Fax
What is emission A3C?
A. Facsimile
B. RTTY
C. ATV
D. Slow Scan TV
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398H-1.2   B 8-2   First digit A for AM |Third digit C for Fax
What type of emission is produced when an amplitude modulated
transmitter is modulated by a facsimile signal?
A. A3F
B. A3C
C. F3F
D. F3C
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