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Tektronix expands 100G electrical test

Tektronix expands 100G electrical test

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By eeNews Europe



Adding to its portfolio of instrumentation and software to support designers working on the electrical side of 100 Gbps communication systems, Tek’s introductions include (pictured above) the LE320, a 2-differential channel, 9-tap linear equaliser supporting data rates up to 32 Gbps as part of a BERTScope receiver test system; new options for the PPG/PED multi-channel BERTs that provide signal impairments and output adjustment at data rates up to 32 Gbps, as well as, a new 40 Gbps error detector model; and Option CEI-VSR that automates the DSA8300 Sampling Oscilloscope to perform required compliance tests for the CEI-28G-VSRstandard.

The need for 4x25G testing is becoming more important as the industry moves from silicon design to transceiver and system design. Designers are creating innovative network elements that allow up to 100 Gbps, which will be delivered using four lanes of 25-28 Gbps. Design challenges emerge when transmitting these high frequencies on printed circuit boards, even for short distances. The LE320 provides test engineers with versatile output signal conditioning and tunable input equalisation to create an optimal system for testing four electrical channels operating at 25-28 Gbps each; a complement to the multi-channel capabilities of the enhanced line of PPG/PED pattern generator and error detector products. The Sampling Oscilloscope Option CEI-VSR will ensure efficient and consistent compliance testing support so that design teams can smooth the transition to manufacturing.

"As 100G moves into the mainstream, we are providing two critical additions to our portfolio that address challenges in 4x25G electrical PHY testing for chips, gearboxes, transceivers and systems," said Brian Reich, general manager, Performance Oscilloscopes, Tektronix. "For receiver testing we’ve enhanced our BERTScope with support for electronic channel modelling and equalisation while adding 40 Gbps support to our multi-channel BERT. And for transmitter electrical testing we are providing designers with an automated solution for CEI-28G-VSR."

Designers developing systems that run at 10 Gbps or faster need an equaliser in front of Rx inputs or a pre-emphasis module on transmitter Tx outputs. As speeds increase, designers have had a limited selection of instrument-grade signal conditioning products beyond 12 Gbps for meeting these requirements. The LE320 will support signal conditioning on data rates from 8 Gbps to 32 Gbps in a 9-tap design used to deliver the high-precision error rate testing required by 100G communication standards such as CEI-28G-VSR.The remote head design of the LE320 enables designers to minimise cable length in their test system and avoid signal degradation issues which are significant at 25-28 Gbps. Based on custom microwave silicon from Hittite to reduce component count, the new LE320 delivers breakthrough performance and versatility in an instrument-grade package not much larger than a smartphone at prices of less than one-third that of less capable alternatives.

With instrument-grade programmable equalisation, the LE320 can be configured to provide standards specific equalisation, permitting bit error rate (BER) analysis on otherwise closed eye signals. For customers working with lower data rates, Tektronix will also offer an LE160 model for systems up to 20 Gbps for such applications as 40G-KR4, 14Gbps Fibre-channel and 16GbpsPCI Express 4.0.

Multi-lane, high data rate standards are driving the need for multi-channel Bit Error Rate instruments. Stressed receiver tests, four-channel end-to-end BER testing, and crosstalk tests are now among of the suite of tests driven by the move to multiple high-speed parallel lanes. The Tektronix PPG/PED line of multi-lane BERTs has now been enhanced to provide expanded jitter impairment capability, new output adjustment flexibility and higher speed error detection capability to better meet the requirement of these standards.

The extended range of jitter insertion options includes option HFJIT which now provides BUJ as well as RJ and SJ; and high amplitude/ low frequency PJ as part of new option LFJIT. Also introduced is option ADJ which adds adjustable outputs with fast rise/fall time and low intrinsic jitter required for 32 Gbps multi-channel pattern generator applications. Data rate margin testing has been enhanced with the introduction of the new PED4000 series of error detector products capable of data rate of up to 40 Gbps, in 1 or 2-channel configurations.

The Implementation Agreement for Optical Internetworking Forum Common Electrical Interface (OIF CEI) 3.0 specifies the tests and limits for devices based on OIF standards. CEI-28G-VSR is one of those standards and is intended for use in very short-reach electrical channels in pluggable optical transceivers. It is critical that these electrical interfaces are able to meet system bit error rate (BER) targets and must undergo rigorous testing and debug cycles.

By using Option CEI-VSR with their Tektronix DSA8300 Sampling oscilloscope, design engineers can perform compliance measurements in less than 5 minutes, reducing their testing time by approximately 95% compared to manual alternatives. In addition, Option CEI-VSR can be used to determine the optimal value for CTLE peaking as required by the CEI-28G-VSR Host-to-Module interface specification. The best CTLE filter is chosen from a given set of filters and used to perform the measurement. Without this capability, design engineers would need to devote time to manually determining the optimal CTLE value, decreasing productivity.

32 Gbps LE320 and 16 Gbps LE160 Linear Equalizers will start at $23,000; PPG3000 Options for Jitter Insertion start at $13,800; and new PED4000 series begins at $102,000.

Tektronix’ President looks to “disaggregation” to shape future instrument designs

In the course of a recent conversation with EDN Europe, Tektronix President Amir Aghdaei reflected on the company’s progress since becoming part of Danaher corporation, some current trends in the T&M sector, and offered a few hints as to directions in which Tek might seek to extend technological leadership.

Among the forces driving T&M technology, Aghdaei identifies – perhaps unsurprisingly – the global trend to total mobility, and the burden this places on his customer base in the sector to integrate RF into overall systems. More specifically, he identifies high-end WiFi (802.11ac) as a problematic area for developers and for operators, in which exacting systems measurements will increasingly be required.

A related, but much wider trend to which Amir Aghdaei believes Tektronix can contribute is that of power-conscious design; almost every engineer is now working with battery-powered or power-constrained designs, and test and measurement systems must offer that dimension as well as their basic domain-specific feature set.

Asked if, in the constant race to stay “one step ahead” of the technology of the devices-under-test, Aghdaei would cite any aspects of the T&M engineering challenge that might require a major change of direction, he mentions the problem of signal capture and access – the need to observe, without disturbing, signals that are increasingly hard to reach. Embedded access tools have a role to play, he says, but also mentions photonic approaches, using optical means to probe ever-faster, ever-smaller quantities.

In a competely different direction, a key term that emerged more than once in EDN’s discussion was “disaggregation” – separation of the attributes of a T&M product, for example to locate the control-and-display attribute of an instrument remotely from the measurement itself. In part this reflects trends such as BYOD (bring you own device) – today’s users want to use their tablets to view data where it is convenient. Is that not just a VXI/PXI/AXI – or other modular standard – instrument by another name? Does this presage a move by Tektronix into more modular products? To both questions, Aghdaei responds that Tektronix remains committed to the fully-featured “conventional” instrument, but will explore more modular concepts. Offering what may be a hint on future product directions, Aghdaei adds, “Modular does not mean a specific architecture; recall that one of the pressures that led to the PXI standard was the need for bandwidth [across an interconnecting bus] – today standards such as USB 3.0 offer wide [data] bandwidths.”

Look back for a full version of this interview with Tektronix’ Amir Aghdaei in a few days time.

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