Electronic Design

BER Testers Handle Tomorrow's Devices As Well As Today's

A trio of bit-error-ratio tester (BERT) products from Agilent Technologies cuts the costs of physical-layer testing today's 3G communications devices. They also should trim the laboratory testing costs of tomorrow's 100-Gbit systems.

The tunable loop-bandwidth clock data recovery (CDR) option for the N4903A JBERT reduces the need for extra cabling and connections, which can degrade the signal. The E4898A BERT front end offers a wide data range and multiple built-in measurements and patterns for testing next-generation optical transceivers. The N5980A 3.125-Gbit/s serial BERT offers low-cost transceiver manufacturing test.

The CDR option for the J-BERT includes a library of standards-compliant CDR settings. The option helps designers get precise jitter-budget results for characterizing and validating devices with clockless architectures. Above 10 Gbits/s, the extra cabling that would be needed could cause up to 5% of a unit interval of extra jitter, reducing design margins. The tunable loop bandwidth lets designers adapt the CDR to proprietary devices and simulate the receiver's jitter filtering so the device's jitter budget can be measured as it's designed to be used. Available on May 1, the CDR option (N4903AU-UTR) costs $26,500.

Agilent expects 100-Gbit/s links to be deployed in metro communications and high-speed server interconnects starting in late 2008. Targeting those applications, the E4898A BERT front end contains multiplexer and demultiplexer technology. It can be used with the 81250 ParBERT (parallel BERT) analyzer module, which measures 1/8-rate sampled signals of up to 12.5 Gbits/s (see the figure). Key specifications include a 40- to 100-Gbit/s data rate, a level range of 200 to 400 mV p-p, a rise/fall time (20% to 80%) of 5 ps, and jitter of 400 fs rms. The E4898A costs $250,000.

The N5980A features measurement rates from 155 Mbits/s to 3.125 Gbits/s. Designed primarily for manufacturing test, it has twice the throughput at one-third the cost of the existing N4906B BERT. It includes simplified transceiver measurements for just the essential tests, controlled by a graphical user interface that runs on an external Windows XP PC via a USB 2.0 connection. It costs $20,000.

Agilent Technologies Inc.

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