Create Custom Composite, Y/C, and RGB Video Test Patterns
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Television or broadcast video signals use a composite method to encode all video information, such as luma (brightness), chroma (color) and synchronization pulses, into one signal. The composite signal method has the advantage of compressing the video information into a small bandwidth, thereby reducing the amount of RF spectrum used when transmitting the signal.
Figure 1. Video Line from Common NTSC Video Test Pattern
When generating video signals for other graphics displays, bandwidth is less of a concern because the signal is never transmitted wirelessly. With a large amount of bandwidth available, the information contained in the composite signal is never combined into one signal. The RGB format uses three signals that represent the intensity of red, green, and blue in the image. The separation of the image data provides higher resolution and improved clarity at the expense of consumed bandwidth.
An NI 5431 Video Signal Generator can produce composite video waveforms used to test broadcast equipment. Using LabVIEW and the NI Video Signal Generator Toolkit software, you can convert custom image test patterns into NTSC, PAL, and SECAM composite video formats and download them into the NI 5431. In addition to converting custom image patterns to composite video, you can also include Insertion Test Signals (ITSs) anywhere in the video signal, giving you complete control over the waveform generated. Virtually all aspects of the video waveform can be adjusted. Attributes such as sync level and color burst amplitude are variable, providing for comprehensive limit testing and characterization of the device under test.
With the synchronization capabilities of modular waveform generators, you can also generate RGB signals. Once again, you can use LabVIEW and the Video Signal Generator Toolkit software to create the R, G, and B signals. You can then download these signals into three tightly synchronized NI 5431s, each one generating one of the three signals.
The same flexible LabVIEW and modular video signal generator can be used to test other video formats such as component video. Component video combines the luma information in one signal, Y, and the chroma information in a second signal, C. Y/C video signals are commonly found in consumer electronics such as DVD players. By synchronizing two NI 5431 video signal generators, you can load the Y and C video signals to test video electronics using the component video format.
Related Links:
RGB Video Generation Using the NI 5431 Video Generator
Generating S-Video Data and Waveforms with the NI-5431
Adding a DC Offset to Video Lines
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