(Last Updated On: January 10, 2020)
This is the Chapter 13: Raster circuits and Sync end chapter exercise in Basic Television – Grob TV as one of the Electronics 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 Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.
Start Grob TV End Chapter Exercise 13
Answers are Underlined
Raster circuits and Sync
- 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
- 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.
- 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.
- 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.
- a. The diagonal black bar represents H scanning.
- b. V Hold control makes the picture stop rolling.
- 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.
- 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
For the TV power supply:
- a. The Tripler is for high voltage.
- b. The voltage regulator is used for the line rectifier.
- a. No horizontal output results in a total loss of the raster since the Flyback high voltage depends on the horizontal output.