# MCQs in Broadcasting and Cable TV System Part IV

Compiled MCQs in Broadcasting and Cable TV System Part 4 of the series as one topic in Electronic System and Technologies (Communications Engineering) in the ECE Board Exam.

This is the Multiples Choice Questions Part 4 of the Series in Broadcasting and Cable TV System as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

### Online Questions and Answers Topic Outline

• MCQs in AM and FM
• MCQs in Television
• MCQs in Studio (Microphone, Amplifiers, Cameras, Lighting, etc.)
• MCQs in Cable Television

### MCQs in Broadcasting and Cable TV System Series

Following is the list of multiple choice questions in this brand new series:

Broadcasting and Cable TV System MCQs
PART 1: MCQs from Number 1 – 50                        Answer key: PART I
PART 2: MCQs from Number 51 – 100                   Answer key: PART II
PART 3: MCQs from Number 101 – 150                 Answer key: PART III
PART 4: MCQs from Number 151 – 200                 Answer key: PART IV
PART 5: MCQs from Number 201 – 250                 Answer key: PART V
PART 6: MCQs from Number 251 – 300                 Answer key: PART VI
PART 7: MCQs from Number 301 – 350                 Answer key: PART VII
PART 8: MCQs from Number 351 – 400                 Answer key: PART VIII
PART 9: MCQs from Number 401 – 450                 Answer key: PART IX
PART 10: MCQs from Number 451 – 500                 Answer key: PART X

### Continue Practice Exam Test Questions Part IV of the Series

151. In the sawtooth waveform for linear scanning the

• a. Linear rise is for flyback
• b. Complete cycle includes trace and retrace
• c. Sharp reversal in amplitude produces trace
• d. Beam moves faster during trace than retrace

152. With vertical retrace time of 635 us, the number of complete horizontal lines scanned during vertical flyback is

• a. 10
• b. 20
• c. 30
• d. 63

153. One-half line spacing between the start positions for scanning even and odd fields produces

• a. Linear scanning
• b. Linear pairing
• c. Fishtailing
• d. Exact interlacing

154. In facsimile transmission, if the drum diameter is 60 mm and scanning pitch is 0.1 mm, calculate the index of cooperation using IEEE recommendation.

• a. 1885
• b. 600
• c. 1900
• d. 984

155. In the interlaced frame, alternate lines are skipped during vertical scanning because the

• a. Trace is slower than retrace
• b. Vertical scanning frequency is doubled from the 30-Hz frame rate to the 60-Hz field rate
• c. Horizontal scanning is slower than vertical scanning
• d. Frame has the aspect ratio of 4:3

156. With ten percent for horizontal flyback, this time equals

• a. 10 us
• b. 5 us
• c. 6.4 us
• d. 83 us

157. Which of the following is not true?

• a. Line pairing indicates poor interlacing
• b. People will look tall and thin on square raster on the picture tube screen
• c. A person can appear to have one shoulder wider than the other because of nonlinear horizontal scanning
• d. The keystone effect produces a square raster

158. The width of a vertical sync pulse with its serrations includes the time of

• a. 6 half lines or 3 lines
• b. Three half lines
• c. Five lines
• d. Five half lines

159. Sawtooth generator circuits produce scanning raster, but the sync pulse are needed for

• a. Linearity
• b. Timing
• c. Keystoning
• d. Line pairing

160. Which of the following frequencies is wrong?

• a. 15, 750 90 Hz for horizontal sync and scanning
• b. 60 Hz for vertical sync and scanning
• c. 31, 500 Hz for equalizing pulses and serrations in the vertical sync pulse
• d. 31, 500 Hz for the vertical scanning frequency

161. The modulated picture carrier wave includes the composite video signal as the

• a. Average carrier level
• b. Symmetrical envelope of amplitude variations
• c. Lower sideband without upper sideband
• d. Upper envelope without the lower envelope

162. Which of the following statements is true?

• a. Negative transmission means the carrier amplitude decrease for black
• b. Negative transmission means the carrier amplitude decreases for white
• c. Vestigial sideband transmission means both upper and lower sidebands are transmitted for all modulating frequencies
• d. Vestigial sideband transmission means the modulated picture carrier signal has only the upper envelope

163. With 2 MHz video signal modulating the picture carrier for channel \$ (66 to 72 MHz), which of the following is transmitted?

• a. 66- MHZ carrier and 68-MHz upper side frequency
• b. 71.75 MHz carrier, with 69- and 73- MHz carrier
• c. 67.25-MHz carrier, with 65.25- and 69.25- MHz side frequencies
• d. 67.25 MHz carrier and 69.25 MHz upper side frequency

164. With 0.5 MHz video signal modulating the picture carrier,

• a. Both upper and lower side frequencies are transmitted
• b. Only the upper side frequency is transmitted
• c. Only the lower side frequency is transmitted
• d. No side frequency are transmitted

165. In all standard television broadcast channels he difference between picture and sound carrier frequencies is

• a. 0.25 MHz
• b. 1.25 MHz
• c. 4.5 MHz
• d. 6 MHz

166. The difference between sound carrier frequencies in two adjacent channels equals

• a. 0,25 MHz
• b. 1.25 MHz
• c. 4.5 MHz
• d. 6 MHz

167. With 7% black setup, maximum black in picture corresponds to what percent amplitude in the modulated carrier signal?

• a. 5
• b. 68
• c. 75
• d. 95

168. Line-of-sight transmission is a characteristic of propagation for the

• a. VHF and UHF bands
• b. VHF bands but not the UHF band
• c. Low radio frequencies below a MHz
• d. AM picture signal but not the FM sound signal

169. In channel 14, 3.58 MHz color signal is transmitted at the frequency of

• a. 471.25 MHz
• b. 473.25 MHz
• c. 474.83 MHz
• d. 475. 25 MHz

170. The difference between the sound carrier and color subcarrier frequencies is

• a. 4.5 MHz
• b. 1.25 MHz
• c. 0.92 MHz
• d. 0.25 MHz

171. Brightness variations of the picture information are in which signal?

• a. I
• b. Q
• c. Y
• d. R-Y

172. The hue 1800 out of phase with red is

• a. Cyan
• b. Yellow
• c. Green
• d. Blue

173. Greater peak-to-peak amplitude of the 3.58-MHz chrominance signal indicates more

• a. White
• b. Yellow
• c. Hue
• d. Saturation

174. The interesting beat frequency of 920 kHz is between the 3.58-MHz color subcarrier and

• a. 4.5- MHz intercarrier sound
• b. Picture carrier

175. The hue of color sync phase is

• a. Red
• b. Cyan
• c. Blue
• d. Yellow-green

176. Which signal has color information for 1.5 MHz bandwidth?

• a. I
• b. Y
• c. R - Y
• d. B – Y

177. Which of the following is false?

• a. I video hues are orange or cyan
• b. The transmitter matrix output includes Y, I and Q video
• c. A three-gun picture tube can serve as a matrix
• d. A full saturated color is mostly white

178. The color with the most luminance is

• a. Red
• b. Yellow
• c. Green
• d. Blue

179. What is the hue of the color 90 degrees leading sync burst phase?

• a. Yellow
• b. Cyan
• c. Blue
• d. Orange

180. The average voltage value of the 3.58 MHZ modulated chrominance signal is

• a. Zero for most colors
• b. Close to black for yellow
• c. The brightness of the color
• d. The saturation of the color

181. The IF value for the color in receivers, for any station, is

• a. 0.5 MHz
• b. 1.5 MHz
• c. 3.58 MHz
• d. 4.5 MHz

182. If the 3.58 MHz C amplifier in the receiver does not operate, the result will be

• a. No color
• b. No red
• c. Too much blue
• d. Too much yellow

183. Which of the following is not tuned to 3.58 MHz?

• a. Burst amplifier
• b. Video preamplifier
• c. Chroma amplifier
• d. Color demodulator input

184. When B – Y and Y signal are combined, the result is

• a. Blue video
• b. 3.58 MHz chroma
• c. Red video
• d. Green video

185. The phase angle between B – Y and R – Y is

• a. 180°
• b. 57°
• c. 0°
• d. 90°

186. Which of the following applies for a monochrome program?

• a. Chroma amplifier on
• b. Y video amplifier off
• c. Color killer on
• d. Picture tube off

187. The manual color control is generally in which circuit?

• a. Red video output
• b. Y video output
• c. Chroma bandpass amplifier
• d. R – Y demodulator

188. The contrast control is generally in which circuit

• a. Red video output
• b. Y video output
• c. Chroma bandpass amplifier
• d. R – Y demodulator

189. If the color oscillator does not operate, the result will be

• a. No picture
• b. No color
• c. Incorrect hues
• d. No color sync

190. The hue of the color sync burst phase is

• a. Red
• b. Blue
• c. Magenta
• d. Yellow-green

191. The balance for Y video signals to the three guns in the picture tube is set by the

• a. Drive controls
• b. Contrast control
• c. Screen control
• d. Color control

192. The voltage wave shape in the output of the vertical amplifier is a

• a. Trapezoid
• b. Sawtooth
• c. Rectangle
• d. Square

193. An auto transformer in the vertical output circuit

• a. Steps up voltage for the scanning coils
• b. Isolates the scanning coils for B+ voltage in the primary
• c. Isolates the oscillator and output stages
• d. Does not isolate the secondary from dc voltage in the primary

194. Vertical flyback pulses at the plate of the vertical output tube are for retrace blanking at the picture tube

• a. Cathode
• b. Control grid
• c. Screen grid
• d. Anode

195. The top of the picture is stretched with too much height. To correct this

• a. Vary the vertical hold control
• b. Reduce height with the vertical linearity control
• c. Increase height with the size control
• d. Replace the vertical oscillator tube

196. Peak-to-peak sawtooth scanning current in the vertical coils can be

• a. 0.7 mA
• b. 0.7 A
• c. 50 A
• d. 150 uA

197. A push-pull amplifier in the vertical output circuit

• a. Usually operates class C
• b. Can use PNP and NPN transistor
• c. Cannot be used
• d. Generally uses two beam-power pentodes

198. Which stage is not necessary for producing horizontal output?

• a. Horizontal oscillator
• b. Horizontal amplifier
• c. Damper
• d. Horizontal AFC

199. The frequency of the sawtooth current in the horizontal amplifier is

• a. 60 Hz
• b. 10500 Hz
• c. 15750 Hz
• d. 70 kHz

200. When the horizontal amplifier is conducting peak plate current, the electron scanning beam is at the

• a. Left edge of the raster
• b. Right edge of the raster
• c. Center of trace
• d. Center of flyback

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