N4967A Serial BERT System 44 Gb/s 40G BER test system

Key features

Operates at data rates from 22 to 44 Gb/s with external clock

Built-in clock for operation at 40 Gb/s

True PRBS pattern generation at full data rate

Supports differential or single ended inputs and outputs

Remote control through USB or GPIB

Compact size

Modular system architecture

The N4967A serial BERT system 44 Gb/s is formed from three main components:

N4974A PRBS Generator 44 Gb/sProvides a true PRBS pattern at full data rate to stimulate the device under test.

N4968A clock and data demultiplexer 44 Gb/sDe-multiplexes the full rate output data stream from the device under test into 4x sub-rate data streams. Also divides the high speed clock to provide a selection of lower speed clock outputs.

N4965A multi-channel BERT 12.5 Gb/sMeasures the bit error rate of the 4x de-multiplexed data streams and provides clock control for the clock and data demultiplexer 44Gb/s.

System configuration

The N4974A PRBS generator 44 Gb/s source can produce PRBS 7, 15, or 31 patterns, providing flexible trade-off between test duration and pattern dependent stress level. An internal low jitter clock source provides operation at 39.8 Gb/s. Alternatively the generator can be clocked from an external source for operation at any rate between 22 and 44 Gb/s (half-rate clock required).

Data outputs are differential, and can be used in single-ended applications by terminating the unused output with a 50 ohm load. The PRBS source also provides pattern trigger and clock outputs, which can be used to trigger a sampling oscilloscope to view the bit stream or a classic eye diagram.

System automation

In both production testing as well as engineering characterization, automation of the system for instrument control and results data collection are essential.

Tools are provided with the N4967A serial BERT system 44 Gb/s system to simplify the setup and integration into an automated test system.

The N4980A multi-instrument BERT software provides a complete user control interface for performing multi-channel BER testing for the N4967A serial BERT system 44 Gb/s. The application computes the BER at the full data rate.

Bar graphs display the computed BER of the full rate data stream, as well as BER on each de-multiplexed data output - giving a quick visual indication of any sub rate related bit errors.