Contents
What should be included in an eye diagram?
Eye diagrams usually include voltage and time samples of the data acquired at some sample rate below the data rate. In Figure 1 , the bit sequences 011, 001, 100, and 110 are superimposed over one another to obtain the final eye diagram. Figure 1 These diagrams illustrate how an eye diagram is formed.
How is an eye diagram different from a phase portrait?
A fundamental difference between the eye diagram and phase portrait is that the latter contains information about the correlation between samples on the time scale of a bit period. This information is absent in eye diagrams that are constructed from samples that are separated by long periods.
Why does the eye diagram deviate from a real situation?
In reality, the transmitter and receiver have a limited bandwidth with noise and jitter, and the transmission media (i.e., optical fiber) has dispersion and nonlinearites. Therefore, the eye diagram deviates from the perfect rectangular shape. Figure 24b shows the eye diagram close to a real situation.
What is the ratio of errors in the eye diagram?
The ratio of bits that have errors, compared to the overall bits, is called BER. The eye diagram does not show protocol or logic problems. It does, however, allow the engineer to more easily view signal impairments in the physical layer in terms of amplitude and time distortion.
What kind of oscilloscope is needed for HDMI 2?
The HDMI standard assumes that the measurement is performed using a real-time oscilloscope (RT scope). With a RT scope, the CRU as well as the formation of the eye diagram are realized in software. Measurements of HDMI 2 signals require an analog bandwidth of >12.5 GHz.
How to interpret the RGB and HDMI standard?
Thus, the HDMI standard must specify how the color space standard (RGB, YUV…) and the subsampling (4:4:4, 4:2:2…). The YCrCb standard implies the YUV color spalce and CrCb or CbCr information order. The numbers after describe subsampling. Now, this is how I would interpret the RGB4:4:4.