148. The most effective method for controlling cochannel interference is to use a
A. low-pass filter
B. high pass filter
C. high-gain antenna with rotor
D. rabbit-ear antenna

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149.  In TV studio lighting, the thumb rule for low-key lighting is
A. to reduce the aperture of the camera lens
B. to cut-off background lights completely
C. to give strong key lights and to cut-off the background lights
D. all above

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150. A TV signal from the antenna is processed by
A. local oscillator
B. RF amplifier
C. transmission line
D. RF tuner

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151.  If for channel No. 7, IF picture frequency is 45.75 mHz, the local oscillator frequency would be ----MHz.
A.221
B.175.25
C.179.75
D.181.25

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152. The primary function of a picture preference diode is to
A. demodulate video signal
B. change resonance frequency of the antenna
C. change the shape of RF resonance curve
D. change the shape of IF response curve

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153. In a TV receiver, IF channel bandwidth is approxiniately
A. 50 kHz
B. 45.75 MHz
C. 3.5 MHz
D. 4.5 MHz

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154. In choosing the lens of TV camera for achieving maximum perception of depth, a ? lens is best choice
A. short focal length
B. long focal length
C. zoom
D. Bi-focal length

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