1.5-GHz bit-error-rate tester also quickly captures eye diagrams
By Dan Strassberg -- EDN, February 6, 2003
The 1.5-GHz BitAlyzer1500 from Synthesys Research includes a proprietary sampling technology that allows the bit-error-rate tester to also create and display images of complete colorized eye diagrams, such as those normally displayed by a high-end oscilloscope or a digital-communications analyzer (Picture). According to the manufacturer, the ability to use a bit-error-rate tester to create eye diagrams is unique and provides users with several technical advantages. First, the technique eliminates the long-standing problem of finger-pointing between the bit-error-rate tester and the oscilloscope when eye diagrams and bit-error-rate results don't match. Second, the tester's bit-for-bit analysis increases the speed of eye-diagram and mask testing by approximately 100 times over statistical sampling in most wideband oscilloscopes. Finally, not having to repeatedly reconnect cables to the scope and the bit-error-rate tester removes a major source of inconvenience and wasted time.
The BitAlzyer1500 also includes built-in ANSI T11.2-defined deterministic- and random-jitter-measurement capabilities. The ANSI specification documents this method as more efficient in data collection than either oscilloscopes or time-interval analyzers because of bit-error-rate testers' inherent ability to continuously sample at high rates over long periods. Previously, a few home-brewed setups using remote-control interfaces implemented the technique, but it was not commercially available as part of a bit-error-rate tester's user interface.
Traditional labs and production-test setups for components and systems often incorporate bit-error-rate testers, oscilloscopes, and, sometimes, jitter-measurement systems to measure both digital errors and eye diagrams. The BitAlyzer1500 combines these functions as well as a high-bit-rate data generator into one higher speed instrument with prices starting at $44,500.
Synthesys Research, 1-650-364-1853, www.synthesysresearch.com/ba1500.htm.
