(Last Updated On: January 10, 2020)
This is the Chapter 14: Color Television Receiver Circuits 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 14
Answers are Underlined
Color Television Receiver Circuits
- a. The Y signal produces a monochrome picture.
- b. The drive controls adjusted for white.
- c. Color red generally does not have a drive control.
- a. When the blue gun is dead, the monochrome picture and raster will be yellow. T
- b. A monochrome picture can be produced without the 3.58-MHz chroma section.
- c. An open in the green output-adder stage results in a magenta picture. T
- a. The value of the beat frequency between the associated sound carrier and color subcarrier is 920 kHz.
- b. The beat frequency between the associated sound carrier and the picture carrier is 4.5 MHz.
- c. The relative gain for 42.17 MHz in the IF amplifier is 50%.
- a. The bandpass amplifier is tuned to 3.58 MHz with a typical bandwidth of +/- .05 MHz. T
- b. The color control varies the gain of the bandpass amplifier. T
- c. The burst amplifier is on during H Flyback time.
- d. A synchronous demodulator needs two input signals. T
- e. The AFPC circuit provides dc control voltage for the color oscillator. T
- f. The tint control adjusts for the phase angle for the demodulated color video signals.
- a. Circuits that can cause the trouble of no color are Bandpass amplifier, color oscillator and color killer.
- b. A fixed phase error in the color oscillator causes wrong hues.
- c. The R-Y demodulator fails, colors red and cyan will be missing from the picture.
- a. The ACC circuit varies the gain of the first BPA.
- b. The manual color control varies the amplitude of the 3.58 MHz chroma signal.
- c. The output from the BPA feed the demodulators.
- d. The burst amplitude used to determine the ACC bias.
- a. The color killer bias is on the PBA. T
- b. Burst is used to produce the dc bias from the color-killer diode detector. T
- c. Color snow, or confetti is predominantly magenta. T
- a. The angle between R-Y and B-Y is 90° .
- b. The bandwidth of the I signal is 1.3 MHz.
- c. DC coupling used for the demodulator output.
- a. The crystal ringer is shock-excited by color burst. T
- b. In an AFPC phase detector, the burst and oscillator cw signals are 90° out of phase.
- c. The burst separator is off during horizontal trace line. T
- d. No color sync means that colors drift through the picture. T
1. Which of the following applies for a monochrome picture? Chroma amplifier off.
2. Which of the following is not tuned to 3.58 Mhz? Video preamplifier
3. The contrast control is in the Y video amplifier.
4. The color level control is in the BPA.
5. The color oscillator does not operate. The trouble is no color.
6. The balance for Y video signals to the three guns in the picture tube is set by the drive controls.
7. Which needs a 0.8ms time delay? Y video.
8. The output of the burst separator feeds the AFPC for color oscillator.
9. The output of the color oscillator feeds the color demodulators.
10. Drifting color bars in the picture indicate trouble in the AFPC for color oscillator.
11. The beat frequency between the 3.58 color subcarrier and the 4.5 Mhz sound signal is 0.92 MHz.
12. Which control varies the phase angle of the color video signal? Tint
13. Which of the following stages has the bias from the AGC and color killer circuits? Chroma BPA.
14. Which of the following stages must be on during horizontal Flyback time? Burst separator.
15. A crystal-ringer circuit is used for the AFPC on color oscillator.