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All-in-One 400GbE PAM4 BER Measurements

21/11/2018

World-Beating Signal Level Quality and Excellent Rx Sensitivity

Anritsu Corporation (President Hirokazu Hamada) announces the release of its 64-Gbaud*1 PAM4*2 Pulse Pattern Generator (PPG) and 32-Gbaud PAM4 Error Detector (ED) supporting 400GbE*3 and Over 400G bit error rate tests.
These modules are installed in the Anritsu Signal Quality Analyzer-R MP1900A series to implement a bit-error-rate test solution with best-in-class signal level accuracy and excellent Rx sensitivity for next-generation broadband communication systems.

[Development Background]

Data traffic volumes are expected to increase due to the spread of next-generation 5G mobile communications and Cloud services. To cope with this demand, infrastructure operators, such as data centers, are investigating not only speed increases but also PAM4 and multilane communications methods.
400GbE speeds are being deployed using either the 26.5625-Gbaud PAM4 x 8 lanes or 53.125- Gbaud PAM4 x 4 lanes methods. When using the PAM4 method expressing data as four amplitude levels, the gap between signal levels is one-third that of the NRZ method, which reduces the unit time per symbol at higher baud rates, emphasizing the importance of signal quality in achieving high-speed transmissions. On the other hand, the inability to avoid degraded signal quality caused by crosstalk and noise resulting from use of multiple lanes and high-density circuit design increases the need for evaluation of minimum Rx sensitivity using stress-test signals.
Consequently, Anritsu has developed the released 64-Gbaud PAM4 PPG with best-of-class signal level quality and the 32-Gbaud PAM4 ED with excellent Rx sensitivity performance to support evaluation of equipment and devices for high-speed, large-capacity transmissions.

[Product Outline]

The Signal Quality Analyzer-R MP1900A is a leading bit error rate tester for the Over 400G market and supports generation of high-speed signals as well as analysis of signal performance.
The newly developed PPG outputting PAM4 signals up to 64 Gbaud has the world’s best Tr/Tf*5 (20% to 80%) time of 8.5 ps (typ.) and Intrinsic Jitter*6 of 170 fs (typ.). Moreover, the multichannel function can be expanded up to 4 channels, and the Emphasis function corrects signals degraded by transmission path loss. The 32-Gbaud PAM4 ED module has a high sensitivity performance of 1623 mV (typ.) and supports installation of a clock recovery function*7 required for Rx sensitivity evaluation, as well as PAM4 symbol error measurements.
As a result, the true performance of 400GbE optical modules and devices, which has been difficult to evaluate accurately due to inadequate signal quality, can now be tested with adequate margin satisfying the specifications. Additionally, the multichannel expandability matching instrument purchase budgets helps cut measurement times using simultaneous measurement of multiple lanes. Moreover, easy combination with jitter and noise addition functions to configure an all-in-one test solution for evaluating Rx sensitivity, helps improve development and testing efficiency.

PAM4 One Box Test Solution

[Click for more details about MP1900A PAM4 BERT]

[Technical Terms]

*1 Gigabaud
Baud is a unit of modulation rate defined as the number of modulations per one second.

*2 PAM
PAM is the abbreviation for Pulse Amplitude Modulation, a transmission method in which the voltage amplitude (pulse height) is controlled. Using PAM4, two bits of information are transferred in one time slot using four voltage levels.

*3 400GbE
This communication standard is defined by IEEE.

*4 Bit Error Rate
The number of errors in a digital signal.

*5 Tr/Tf
The time required for the digital signal level transition.

*6 Jitter
Signal fluctuation in the time domain caused by noise, etc., in internal circuits.

*7 Clock Recovery
A technology used by digital transmissions to extract the clock from the received data signal with superimposed clock.

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