Start Grob TV End Chapter Exercise 13
Answers are Underlined
Chapter 13
Raster circuits and Sync
13-1
- a. All the sync pulses have the same amplitude. T
- b. The synchronizing pulses produce the scanning raster. F
- c. The V sync pulse has the lowest frequency. T
13-2
- a. The sync separator is a common-emitter amplifier.
- b. The separated sync includes all the sync pulses. T
- c. The separated sync is inverted from the pulses in the composite video signal. T.
13-3
- a. The input for the V integrator is taken from the sync separator.
- b. The output from the RC integrator is the voltage across C.
- c. A typical time constant for the vertical integrator is 50 µs.
13-4
- a A single bright line across the center of the screen can be caused failure of the oscillator or amplifier or a defect in the coupling circuits or yoke.
- b. Too much black space at the bottom of the screen can be caused by weak vertical output.
- c. The dc bias on the vertical amplifier affects the height and linearity of the raster.
13-5
- a. The diagonal black bar represents H scanning.
- b. V Hold control makes the picture stop rolling.
13-6
- a. HAFC – Horizontal AFC. It is a PLL.
- b. HAFC is for horizontal sync.
- c. Horizontal Flyback is for high voltage.
- d. The output stage operates similar to class c amplifier.
13-7
- a. The gen-lock system is used in television cameras and other studio equipment to provide the V and H drive signals. It provides excellent interlacing.
- b. The whole gen-lock circuit can be contained in one dedicated chip. T
- c. The master oscillator operates at 31.5 khz.
- d. No vertical hold is used. T
13-8
For the TV power supply:
- a. The Tripler is for high voltage.
- b. The voltage regulator is used for the line rectifier.
13-9
- a. No horizontal output results in a total loss of the raster since the Flyback high voltage depends on the horizontal output.
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