An eye diagram with compliance masks is shown in Figure 6 below. 1 overcomes the limitations of a single-value display by overlapping all of the possible one-zero combinations on the oscilloscope screen.
DPOJET is the premiere eye-diagram jitter noise and timing analysis package available for real-time oscilloscopes.
Eye diagram oscilloscope display. Accelerating data rates greater design complexity standards requirements and shorter cycle times put greater demand on design engineers to debug complex signal integrity issues as early as possible. Then successive waveforms accumulate to form a composite image in the manner of tracks in the snow. Eye Diagram Test Setup Pulse Generator Oscilloscope Data DUT Clock The Pulse Generator is required to generate a random bit pattern since the eye diagram is a statistical average of.
Once you have your clock recovery system set up all you have to do to set up the eye is press auto setup. For easy viewing the time axis in Figure is normalized for bits with the 1 bit eye opening in the center. If the data pattern is repeating and the length of.
It then describes different ways that information from an eye diagram can be sliced to gain more. To display the eye diagram the clock recovery unit CRU is used to recover the data clock from the TMDS clock see Fig. You will see in just a few seconds that the eye diagram has begun to form.
In the oscilloscope an eye diagram is often used to analyze signal quality. Generally you will want to let the test run for a longer period of time. In a radio system the point of measurement may be prior to the modulator in a transmitter or.
Next they had to trigger the oscilloscope with clock signal turn up the persistence and if. Because todays serial data links operate at gigahertz transmission frequencies a host. Operating in the Tektronix DPODSAMSO70000 DPO7000 and MSODPO5000 Series oscilloscopes DPOJET provides engineers the highest sensitivity.
You can diagnose problems such as attenuation noise jitter and dispersion that arise or. Acquisitions for creating the worst-case jitter condition in the eye diagram. The eye diagram is used primarily to look at digital signals for the purpose of recognizing the effects of distortion and finding its source.
The recovered clock is used to trigger the oscilloscope which lays all waveforms over each other. Full rate clocks as well as divided clocks will gen-erate an eye diagram. The eye diagram is an oscilloscope display of a digital signal repetitively sampled to get a good representation of its behavior.
An eye diagram or eye pattern is simply a graphical display of a serial data signal with respect to time that shows a pattern that resembles an eye. An eye diagram Fig. Eye diagrams are multivalued displays because each point in the time axis has multiple voltage values.
To demonstrate using a Tektronix MDO3104 oscilloscope we connect the AFG output on the back panel to an analog input channel on the front panel and press AFG so a sine wave displays. Over time you will be able to see if there is any jitter or anomalies in your signal. DP 14 Eye Diagram Changes TEKTRONIX DISPLAYPORT 14 WEBINAR 2017 10 Find the optimal CTLE and DFE and create a waveform using this value.
When constructing the eye diagram. To perform an eye mask test engineers used to draw a mask on the display of an analog oscilloscope with a grease pencil. The eye diagram shows up in an oscilloscope display when the instrument is placed in the infinite persistence mode.
Determined by using a compliance mask overlay on the eye diagram display. A Digital Phosphor Oscilloscope DPO in. Abstract This paper describes what an eye diagram is how it is constructed and common methods of triggering used to generate one.
Reveals the eye of the eye diagram as shown in Figure. Using a digital storage oscilloscope might take the user about an hour to accumulate one million acquisitions. How to relate eye-mask tests to BER.
An eye diagram is a pattern shown on an oscilloscope that depicts a fuller view of what a digital signal stream looks like from a more holistic viewpoint one could say. Whats actually happening is that the oscilloscope is receiving or sampling a digital signal a stream of step functions that represent 0s and 1s in varying patterns. Reading and applying eye diagrams.
Use these values for performing the eye diagram measurement. Eye diagram measurement with an oscilloscope can help users visually display the transmission quality of digital signals thereby understanding the strength of crosstalk between codes in the system and making improvements in. Eye diagram basics.
The signal at the receiving end of the serial link is connected to an oscilloscope and the sweep rate is set so that one or two bit time periods unit intervals or UI are displayed. But there are some important considerations when using divided clocks. See Figures 621 and 622.
A typical mask includes both time and amplitude limits.