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135 lines
2.5 KiB
Plaintext
135 lines
2.5 KiB
Plaintext
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% FILENAME = N19.TXT
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% Transmitter Theory
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% Release version 2, January 00
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%QUESTION: 1
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#19.1 Morse code is usually transmitted by radio as:
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an interrupted carrier
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a voice modulated carrier
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a continuous carrier
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a series of clicks
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% ans 1
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%QUESTION: 2
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#19.2 To obtain high frequency stability in a transmitter, the VFO should be:
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run from a non-regulated AC supply
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in a plastic box
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powered from a regulated DC supply
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able to change frequency with temperature
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% ans 3
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%QUESTION: 3
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#19.3 SSB transmissions:
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occupy about twice the bandwidth of AM transmissions
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contain more information than AM transmissions
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occupy about half the bandwidth of AM transmissions
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are compatible with FM transmissions
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% ans 3
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%QUESTION: 4
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#19.4 The purpose of a balanced modulator in a SSB transmitter is to:
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make sure that the carrier and both sidebands are in phase
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make sure that the carrier and both sidebands are 180 degrees out of phase
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ensure that the percentage of modulation is kept constant
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suppress the carrier while producing two sidebands
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% ans 4
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%QUESTION: 5
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#19.5 Several stations advise that your FM simplex transmission in the "two metre" band is
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distorted. The cause might be that:
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the transmitter modulation deviation is too high
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your antenna is too low
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the transmitter has become unsynchronised
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your transmitter frequency split is incorrect
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% ans 1
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%QUESTION: 6
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#19.6 The driver stage of a transmitter is located:
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before the power amplifier
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between oscillator and buffer
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with the frequency multiplier
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after the output low-pass filter circuit
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% ans 1
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%QUESTION: 7
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#19.7 The purpose of the final amplifier in a transmitter is to:
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increase the frequency of a signal
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isolate the multiplier and later stages
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produce a stable radio frequency
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increase the power fed to the antenna
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% ans 4
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%QUESTION: 8
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#19.8 The difference between DC input power and RF power output of a transmitter RF amplifier:
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radiates from the antenna
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is dissipated as heat
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is lost in the feedline
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is due to oscillating current
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% ans 2
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%QUESTION: 9
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#19.9 The process of modulation allows:
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information to be impressed on to a carrier
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information to be removed from a carrier
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voice and Morse code to be combined
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none of these
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% ans 1
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%QUESTION: 10
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#19.10 The output power rating of a linear amplifier in a SSB transmitter is specified by the:
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peak DC input power
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mean AC input power
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peak envelope power
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unmodulated carrier power
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% ans 3
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