Error detector with high PAM4 Rx sensitivity at ECOC

3rd September 2019

Alex Lynn

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With what the company believes to be the world’s highest operation bit rate and Rx sensitivity, this new ED module for Anritsu’s popular Signal Quality Analyser-R MP1900A Series PAM4 BERT supports high-accuracy Bit and Symbol Error Ratio measurement of PAM4 signals when combined with the previously released PAM4 Pattern Signal Generator.

Communications data traffic volumes are expected to grow with the spread of next generation 5G mobile communications and Cloud computing services. As a result, data centres supporting fast, large-capacity communications are examining speed increases to 400GbE using four 53.125-Gbaud PAM4 lanes as well as future upgrades to 800GbE using eight PAM4 lanes.

Since the PAM4 method expresses two bits of data with four amplitude levels, it has one-third the signal level difference of the NRZ method using two levels, thus requiring instruments to have much higher input sensitivity performance, to evaluate signal quality (integrity).

Moreover, at faster speeds, it is no longer possible to ignore the effects of losses from components, such as PC boards, cables, connectors in the transmission path, on measured results. As a consequence, evaluating the true performance of the devices under test requires not only excellent fundamental performance such as sensitivity and frequency bandwidth, but also high-level integrated functions, such as Clock Recovery and Equaliser, to compensate for the impact of losses.

Anritsu developed this new Error Detector with built-in clock recovery and equaliser functions, to implement worldwide highest sensitivity performance for PAM4 BER measurements.

The Signal Quality Analyser-R MP1900A Series PAM4 BERT is the market-leading Bit Error Rate Tester for communications speeds at 400G and above and supports high quality signal generation and analysis. The new PAM4 ED module uses a unique InP (Indium phosphide compound) semiconductor Rx circuit to achieve a sensitivity performance of 50mV (typ.) for a 58-Gbaud PAM4 input.

The built-in clock recovery and equaliser functions, and transmission path compensation, support never-before-seen validation of BER measurement results.

As an additional unique value in the market, multichannel signal generation, combined with FEC patterns emulation and jitter tolerance testing, enables accurate evaluation of the true performance of optical transceiver modules and devices, as well as specification margins, in real life working conditions. Hirokazu Hamada, Anritsu’s President comments.