Start Grob TV End Chapter Exercise 10
Answers are Underlined
CHAPTER 10
Video Tape Recorders and Disk Players
10-1
- a. The range of 30 to 40 Hz is 3 octaves. T
- b. Frequency modulation is used for video signals.
- c. In video recording, both the tape and the head gap are in motion. T
- d. The VCR and TV receiver must be operating on the same channel in order to record. F
10-2
- a. Which is nonmagnetic, the head core, the gap or the tape? Gap
- b. The high-frequency response improved with a thinner head gap.
- c. There are 2 octaves in a range of 4:1 in frequencies equal.
10-3
- a. The frequency range of the recorded FM signal is less than 3 octaves.
- b. For video recording FM is better than AM. T
- c. In the VHS and Betamax systems, the luminance signal is modulated for recording. T
10-4
- a. The luminance is recorded as an FM signal.
- b. A 700 kHz is a color-under.
- c. In VHS system, 3.58 MHz corresponds to 629 kHz color under frequency.
- d. The highest frequency to be played back in a typical VCR is 5 – 6 MHz.
10-5
- a. One TV field does a slant track record in one pass.
- b. The angle of wrap that the tape makes around the scanner head slightly is more than 180°.
- c. Head switching takes place at the bottom of the TV picture.
- d. Increasing the drum diameter increases the writing speed.
10-6
- a. The timing reference for the scanner servo in the recording is the V sync divided by 2. T
- b. A tone generator on the scanner shaft indicates the frequency of rotation. T
- c. A pickup coil next to a magnet on the scanner shaft indicates the position of the reference video head. T
- d. A sample-and-hold circuit is used as a timing comparator. T
10-7
- a. The control and audio are the two stationary recording heads.
- b. Tape speed is controlled by the capstan.
- c. The poor tracking of the video heads causes snow in the picture.
- d. The exact frequency of the CTL pulses is 29.97 Hz.
10-8
- a. In the zero guard-band system, at 6 or 7° is the angle in each head canted.
- b. The canted azimuth angle work better for luminance signals.
- c. The time delay of the comb filter is 1H or 63.5 µs.
- d. The frequency that is the 455th harmonic of H/2 is 3.579545 MHz.
10-9
- a. The supply reel of tape in the video cassette is at the left side. T
- b. The audio track can be erased, but the video tracks cannot. F
- c. The audio and the control heads rotate in the same direction as the scanner. F
10-10
- a. The CED system is based on variations in capacitance. T
- b. The VLD system requires a laser light beam.
- c. Videodisk machines are generally used for playback but not for recording. T
10-11
- a. A laser source produces coherent light. T
- b. The recorded pits on an optical videodisk vary in depth. F
- c. The color-under process is necessary in optical videodisk recording. F
10-12
- a. The CED and VHD systems both use capacitance variations for signal. T
- b. The deeper the pit in a disk, the lesser the capacitance.
- c. The color-under system is used in the CED method bit not for optical disks. T
- d. Disk rotation is 450 rpm in the CED system.
From the multiple choice questions:
1. How many octaves is the frequency range of 1 to 8? 3
2. Which system can be used for both recording and playback? VHS
3. How many TV fields are recorded on one slant track of tape? 1
4. The video heads rotate at high velocity to increase the writing speed.
5. A typical frequency for the FM luminance signal in VCR recording is 3.5 Mhz.
6. Which of the following applies to the color-under technique? Chroma frequencies are reduced.
7. What oscillator frequency is needed to heterodyne 629 khz up to 3.58 Mhz? 4.21 Mhz
8. A comb filter is used to cancel chroma crosstalk.
9. Switching for each field is required for the video heads.
10. Servocontrol of speed and phase is used for the video scanner head.
11. The part that rotates to meter o the tape at constant speed is capstan.
12. To make the tape speed the same in playback as in recording, the tape speed is regulated by the control-track pulses.
13. Tilting the video head gaps is necessary with the zero guard bands.
14. Which system uses a laser light beam for playback? VLP
15. In the CED system, the disk capacitance varies with the pit depth.
Post a Comment