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Test Solutions Take Aim At High-Speed Physical Layer

These test sources, analyzers, and modules arm high-speed digital designers to evaluate components and networks operating at electrical and optical rates to 40 Gb/s.

High-speed serial-communications networks are delivering data and video at unprecedented (microwave) speeds. As the transmission rates increase, characterization of the networks and their component parts becomes more difficult, requiring special measurement tools. One of these is a set of new options for the Agilent J-BERT N4903A serial bit-error-rate tester (BERT) that add calibrated jitter injection capabilities for checking the effects of jitter on component and system performance, while another is the Agilent N4916A De-Emphasis Signal Converter for evaluating systems and circuits using de-emphasis techniques to compensate for signal losses.

The J-BERT N4903A is available with 7- and 12.5-Gb/s pattern generator options for creating high-speed digital test signals. While the generators can be used for injecting ideal distortion-free signals into a component or system, engineers can also choose to dial in a desired amount of jitter (timing instability noise), including random jitter, periodic jitter, and bounded uncorrelated jitter. An additional option allows control of inter-symbol interference (ISI) in the generated test signals. The J-BERT N4903A sources feature 20-ps 20-to80-percent transition times and 9-ps peak-to-peak jitter.

The Agilent N4916A De-Emphasis Signal Converter (see figure) allows injection of de-emphasis signals when used as a front end for the company's J-BERT N4903A serial bit-error-rate tester (BERT) and 81141/2A Serial Pulse Pattern Generator. De-emphasis signals are often employed in high-speed digital systems and circuits to compensate for signal losses and degradation through printed-circuit boards (PCBs), circuit traces, cables, and backplanes. By controlling de-emphasis injection in 0.5-dB steps, the N4916A and J-BERT can analyze channel effects under various de-emphasis and signal conditions, covering data rates to 13.5 Gb/s.

The company also added new software, a clock-recovery module, and an optical/electrical (OE) module for their Digital Communications Analyzer (DCA-J) to aid high-speed digital circuit designers. The software allows phase noise and jitter analysis of clock and data signals. When used with the Agilent 83496B Clock Recovery Module, the combination supports phase-noise and jitter testing for signals from 50 Mb/s to 13.5 Gb/s, including spread-spectrum clocking (SSC) signals.

When the DCA-J is equipped with the Agilent 86116C optical/electrical module, the combination can be used as a 65-GHz oscilloscope channel or as a reference receiver for 40-Gb/s optical transmitter eye-mask tests. It can be configured for OC-768, STM256, and other high-speed digital performance verification testing. An additional option (300) for the DCA-J enables amplitude modulation measurements, such as testing of relative intensity noise (RIN) in optical components and systems. P&A: $122,000 (J-BERT Pattern Generator with 7-Gb/s option), $138,000 (J-BERT Pattern Generator with 12.5-Gb/s option), $18,5000 (clock recovery module), $64,089 (optical/electrical module), and $40,000 (N4916A de-emphasis signal converter for J-BERT).

Agilent Technologies, Inc., Test and Measurement Organization, 5301 Stevens Creek Blvd., MS 54LAK, Santa Clara, CA 95052; Internet:

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