Agilent Eyescn Technology

Digital designers are becoming increasingly aware of design problems associated with crosstalk, intersymbol interference and clock and data jitter. A designer must understand the concept of a Data Eye when talking about high speed buses. It is important to consider not only the width of the data valid window, measured in time, but its height as well, measured in voltage. The Data Eye is the single measurement that captures both of these considerations. Finding and maintaining the size of the Eye is the principal challenge in designing and validating high speed busses.

Measuring The Eye

If you put a scope in infinite persistence and let it run repetitively, you build up the familiar eye diagram. The name comes from the fact that it looks like an eye, but also through the eye you can see a lot about the performance characteristics of your circuit and how well it's meeting your signal integrity goals.

However, using a scope on multiple signals of a high speed bus can take hours. Agilent has just introduced a new technology called "Eye Scan", which uses the 16700B / 16702B Logic Analysis System to make the measurements. An Eye Scan of up to 169 signals can take as little as 5 minutes. A list of supported logic analysis modules can be found below.

Eye Scan Benefits

• Compare signal quality on many signals in minutes
• Archive measurements for later examination
• Quickly verify signal integrity during environmental testing
• Reduce project risk due to signal integrity issues
• Deliver a more reliable product in less time

Some FuturePlus analysis probes incorporate active circuitry and are not appropriate for Eye Scan measurements. The passive analysis probes, however, are ideal for making Eye Scan measurements. You can contact our technical support department if you are not sure.

• 16753A - 1 MB, 600 MHz State/1.2 GHz Timing
• 16754A - 4 MB, 600 MHz State/1.2 GHz Timing
• 16755A - 16 MB, 600 MHz State/1.2 GHz Timing
• 16756A - 64 MB, 600 MHz State/1.2 GHz Timing
• 16760A - 128 MB, 1250 MHz State/800 MHz Timing
• 16950A - 1-16 MB, 600 MHz State/1.2 GHz Timing

For a complete up to date list, check out Agilent's logic analyzers.