Objectives:
1.1 Getting to know the video camera.
1.2 Measuring the composite video on a video camera.
1.3 Determining the parameters of composite video.
1.1 Getting to know the video camera.
1.2 Measuring the composite video on a video camera.
1.3 Determining the parameters of composite video.
Equipment Used:
1 Video Camera
1 Oscilloscope 40 MHz and passive probe
1 RCA cable connector - BNC (75 W)
Introduction:
A comprehensive idea of a TV camera function is depicted in Figure 3-2 and 3-3. In Figure 3-2 the camera is aimed at scene / view so that the optical image (optical image) can be focused on the target plate tube makers (pick-up tube). If you can look inside, you'll see the shadow-optical. The resulting video signal is shown by the oscilloscope waveform in the bottom left of the picture. Above is a monitor oscilloscope, which shows a reproduced image.
Details of the video signal waveform which is more fully shown by the block diagram in Figure 3-3. At first, blanking pulses added to signal the camera. They cause the signal amplitude to the black levels so pengulangjejakan (retrace) the MRV will not be visible. Further alignment pulses (sync) is inserted. Alignment (synchronization) is required to set the time & MRV horizontal and vertical. Camera signal with blanking and synchronization (sync) is called a composite video signal (composite video signal). Sometimes the term is not a composite video signal (noncompoxite video signal) is used to identify the signal with blanking camera but without alignment. Standard output level of the composite video signal from the camera is 1Vpuncak-to-peak (pp = peak to peak) with the alignment pulses in the down position for negative polarity
Experimental Procedure
1. Set-up devices such as a picture he bag, connect the video camera out with input CRO.
2. ON the instrument.
3. Set the appropriate CRO to be easily observed (MODE on the TV-H position and / or TV-V).
When seeing a wave of horizontal synchronization MODE switch put on the TV-H position, while to see a wave of vertical sync put the MODE switch on the TV-V position.
4. Specify the synchronization pulses, blanking pulses, front and rear porch, and image information.
5. Image of the wave form and specify voltage.
1. Set-up devices such as a picture he bag, connect the video camera out with input CRO.
2. ON the instrument.
3. Set the appropriate CRO to be easily observed (MODE on the TV-H position and / or TV-V).
When seeing a wave of horizontal synchronization MODE switch put on the TV-H position, while to see a wave of vertical sync put the MODE switch on the TV-V position.
4. Specify the synchronization pulses, blanking pulses, front and rear porch, and image information.
5. Image of the wave form and specify voltage.
Basic theory
Horizontal synchronization
A horizontal synchronization pulse is sent whenever the television set should start scanning a new line. The rest of the scan line follows, with the signal ranging from 0.3 V (black) to 1 V (white), until the next horizontal or vertical synchronization pulse.
The format of the horizontal sync pulse varies. In the 525-line NTSC system it is a 4.85 µs-long pulse at 0 V. In the 625-line PAL system the pulse is 4.7 µs synchronization pulse at 0 V . This is lower than the amplitude of any video signal (blacker than black) so it can be detected by the level-sensitive "sync stripper" circuit of the receiver.
The format of the horizontal sync pulse varies. In the 525-line NTSC system it is a 4.85 µs-long pulse at 0 V. In the 625-line PAL system the pulse is 4.7 µs synchronization pulse at 0 V . This is lower than the amplitude of any video signal (blacker than black) so it can be detected by the level-sensitive "sync stripper" circuit of the receiver.
Vertical synchronization
A vertical synchronization pulse is sent whenever the television set should start scanning a new frame from the top of the screen.The format of such a signal in 525-line NTSC is:
-
- pre-equalizing pulses (6 to start scanning odd lines, 5 to start scanning even lines)
- long-sync pulses (5 pulses)
- post-equalizing pulses (5 to start scanning odd lines, 4 to start scanning even lines)
Each pre- or post- equalizing pulse consists in half a scan line of black signal: 2 µs at 0 V, followed by 30 µs at 0.3 V.
Each long sync pulse consists in an equalizing pulse with timings inverted: 30 µs at 0 V, followed by 2 µs at 0.3 V.
In video production and computer graphics, changes to the image are often kept in step with the vertical synchronization pulse to avoid visible discontinuity of the image. Since the frame buffer of a computer graphicspage tearingartifact partway down the image.
Vertical synchronization eliminates this by timing frame buffer fills to coincide with the vertical blanking interval, thus ensuring that only whole frames are seen on-screen. Software such as computer games and CAD packages often allow vertical synchronization as an option, because it delays the image update until the vertical blanking interval. This produces a small penalty in latency, because the program has to wait until the video controller has finished transmitting the image to the display before continuing. Triple buffering reduces this latency significantly.
VSYNC is also the name of the signal indicating this frame change in analog RGB component video.
display imitates the dynamics of a cathode-ray display, if it is updated with a new image while the image is being transmitted to the display, the display shows a mishmash of both frames, producing a
Each long sync pulse consists in an equalizing pulse with timings inverted: 30 µs at 0 V, followed by 2 µs at 0.3 V.
In video production and computer graphics, changes to the image are often kept in step with the vertical synchronization pulse to avoid visible discontinuity of the image. Since the frame buffer of a computer graphicspage tearingartifact partway down the image.
Vertical synchronization eliminates this by timing frame buffer fills to coincide with the vertical blanking interval, thus ensuring that only whole frames are seen on-screen. Software such as computer games and CAD packages often allow vertical synchronization as an option, because it delays the image update until the vertical blanking interval. This produces a small penalty in latency, because the program has to wait until the video controller has finished transmitting the image to the display before continuing. Triple buffering reduces this latency significantly.
VSYNC is also the name of the signal indicating this frame change in analog RGB component video.
display imitates the dynamics of a cathode-ray display, if it is updated with a new image while the image is being transmitted to the display, the display shows a mishmash of both frames, producing a
source : WIKIPEDIA.COM
RESULT EXPERIMENT
Conclussion :
There are two type of syncronization it is, horizontal sync and vertical sync, each syncronization mark by blank pulse (show in picture), the signal betwen blank pulse it is information that contain analog date.
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