RELATED MATERIAL Option SF: Symbol Filtering Product Brief (PDF) USB 3.0 Brochure (PDF)

Asynchronous BER
and Jitter Tolerance Testing

Symbol Filtering on the BERTScope enables asynchronous Bit Error Ratio (BER) testing, including Jitter Tolerance testing, on incoming data streams that have a non-deterministic number of clock compensation symbols inserted into the bit stream. This is a key capability needed in testing 8b/10b serial data systems such as USB 3.0 and SATA.

It is common in 8b/10b encoded serial data systems to use a recovered clock in the receiver. However, there could be a slight mismatch in the recovered clock frequency and the local or transmitted clock frequency, which poses a problem when testing receivers in loopback mode. Transceivers accommodate this mismatch by use of inserted or deleted clock compensation patterns. For example, USB 3.0 uses SKP ordered sets, and SATA uses ALIGN primitives.

By filtering out these user-definable symbols, the Symbol Filtering option enables the BERTScope to maintain synchronization and perform BER measurements for applications such as USB 3.0 and SATA receiver compliance testing.

This transceiver’s local clock is slightly faster than the recovered clock. To compensate, the transmitter has inserted an extra SKP. With Symbol Filtering, the BERTScope can handle any number of contiguous clock compensation patterns for accurate BER or Jitter Tolerance testing.

Key Features:

• User-specified symbols are automatically filtered from the incoming data
• Supports BER and Jitter Tolerance Testing
• Patterns of symbols from one to four in length can be targeted for filtering, such as SKPs used in USB 3.0, or ALIGNs in SATA
• Running Disparity (RD) is automatically taken into account and both positive and negative RD bit sequences for the chosen symbols are filtered
• Filters multiple contiguous patterns of symbols appearing as close as 64 bits apart
• The BERTScope Detector maintains a count of filtered bits
• Operates at data rates up to 11.2 Gb/s

Ordering Information

Contact a SyntheSys sales representative.

To learn more about how BERTScope can meet your testing needs, or to schedule a demonstration in your lab, contact our Sales Engineers.