22. The output from a keyed-rainbow generator generates a colour pattern on the TV screen called the pattern.
A. bar
B. rainbow
C. ring
D. colour-difference

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23.  In practice, it is desirable to prevent vertical rolling of chroma bars because of the
A. loss of contrast
B. frequency drift in vertical oscillator
C. snaking action caused by the 50 Hz and 100 hz hum voltage
D. none of the above

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24.  Colour bar generators are used mainly to check the operation of the ........... in colour TV receivers.
A. number of chroma bars
B. chroma circuitry
C. video
D. RF

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25.  A vectorgram is useful because it shows at a glance whether the operation of the .......... is normal.
A. RF amplifier
B. horizontal amplifier
C. chroma demodulator
D. video amplifier

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26. The control that adjusts the frequency of the horizontal sweep oscillator in an oscilloscope is
A. sync selector
B. Z-axis
C. horizontal gain
D. sweep control

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27.  The probe commonly used on the oscilloscope when measuring high-frequency or high-impedance circuits is the
A. low-capacitance probe
B. voltage divider
C. demodulator probe
D. noise probe

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28.  The accessary probe that is used on the oscilloscope for detecting signal is
A. low-capacitance probe
B. AF probe
C. demodulator probe
D. direct probe

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