Adjustable & integrated inter-symbol interference in a BERT

January 23, 2015 // By Graham Prophet
Streamlining high-speed digital receiver characterisation, Keysight Technologies has added an adjustable and integrated intersymbol interference (ISI) capability for the J-BERT M8020A high-performance BERT (bit-error-rate tester).

When engineers characterise and test high-speed digital receivers for compliance, they often need to emulate a certain channel loss. The adjustable and programmable ISI function allows engineers to emulate channel loss. This function is integrated in each pattern generator channel of the J-BERT M8020A, which streamlines test setup by eliminating the need for external cabling and the need to switch external ISI traces.

When R&D and validation teams characterise next-generation digital designs, they face several test challenges. As data rates continuously increase, channel loss between transmitter and receiver becomes more important. The loss is caused by printed circuit board traces, connectors and cables in the signal path. This channel loss results in ISI that depends on the channel material and dimensions, the data rate and bit pattern. All high-speed digital receivers are specified to tolerate a certain amount of total jitter, which typically includes some ISI caused by channel loss. During receiver characterisation and compliance test, engineers need to emulate this loss. To emulate channel loss in the past, engineers used external trace boards that required external cabling and switching, which required time-consuming setup and contributed to test complexity.

“The M8020A high-performance BERT enables fast and accurate receiver characterisation and compliance testing with today’s highest level of integration,” said Juergen Beck, general manager and vice president of Keysight’s Digital and Photonic Test Division. “With its integrated and adjustable ISI capability, the M8020A sets a new standard to help engineers master the test challenges for next-generation high-speed digital designs.”

The J-BERT M8020A high-performance BERT accelerates insight into digital designs. It offers fast and accurate receiver characterisation for single- and multilane devices operating at data rates up to 16 Gb/sec and 32 Gb/sec. The built-in ISI functionality is programmable for each pattern generator channel, simplifying receiver test automation by eliminating cabling and switching of external traces for data rates up to 16 Gb/sec. The ISI option provides accurate and repeatable results for