Waveform generator tests serial data receivers

The Tektronix AWG7000 arbitrary waveform generator has been approved for direct synthesis testing of Serial ATA data receivers

Tektronix has made significant advances in the application of direct synthesis (DS) for high speed serial receiver compliance testing. Direct synthesis is a flexible and repeatable method for creating ideal or impaired waveforms that are then directly synthesised by the Tektronix AWG7000 arbitrary waveform generator.

This enables precise and uniform testing of high speed serial data receivers, yielding higher quality computing and consumer electronic devices.

Direct synthesis with the AWG7000 was approved as a normative test technique for the SATA Interop Workshops (IW) and applied to products seeking SATA IW certification during the recent SATA-IO Interop Workshop in Milpitas, California.

As datarates continue to increase, the reduction in timing margins has forced the industry to adopt much more rigorous and comprehensive test methods.

One of the last areas of test coverage has been in the field of receiver testing.

The complexity of this testing has been a principal challenge, and the problems with obtaining consistent settings between high speed NRZ generators with the needed levels of specification mandated impairments by standards organisations are real and substantial impediments to the successful deployment of these test practices.

Use of external, intersymbol interference generating hardware in conjunction with microwave mixing of sinusoidal terms leads to laboratory setups that are challenging to reproduce with any level of certainty.

Direct synthesis with the AWG7000 enables repeatable serial data measurements with an unprecedented degree of simplicity, flexibility and speed for high speed serial data receiver compliance testing.

'Designers have had to rely almost exclusively on digital data generators to produce the binary signals for their serial tests', said Jit Lim, Manager, Technology Solutions Group, Tektronix.

'These solutions are complicated, expensive, and can produce inconsistent results'.

'New entries in the signal source realm such as the Tektronix AWG7000 with direct synthesis capabilities are changing that'.

'The DS capabilities of the AWG7000 allow engineers to easily create signals that embody the effects of propagation through a transmission line'.

'Rise times, pulse shapes, delays, and aberrations all can be controlled'.

'This is exactly what needs to be done for rigorous serial bus testing'.

Tektronix has pioneered the development and deployment of a fully direct synthesis technique for high speed serial data testing.

Engineers are able to simply recall a setup file that encapsulates all of the relevant standard, mandated jitter terms and signal impairments, without the need for any additional external components or mixing required.

AWG setup file deployment can be managed through electronic circulation of files, enabling systems worldwide to be synchronised to a common and consistent level of generation properties with no external hardware dependencies.

'Direct synthesis with the AWG7000 offers the ultimate in flexibility of waveform creation, with very competitive cost of test, and greater measurement repeatability than other solutions that use complex collections of signal generation boxes and modules', said Bob Buxton, Marketing Manager, Signal Source Product Line, Tektronix.

'Direct synthesis can be used to emulate all forms of channel impairments and even provides the capability to pre-compensate for losses in the overall test setup and cabling, something no digital signal generation product can do'.

The versatility and breadth of coverage of a single AWG7000 based system allows easy design and conformance testing to a multitude of technologies or standards with the press of a button.

With 10bit vertical precision and 20Gsample/s sample rate, the AWG7102 is extremely versatile for any form of complex signal generation.

From complex equalisation schemes, multi level signalling and pre-emphasis to being able to sweep ISI with a continuity from zero, to multiple UIs of jitter with digital precision, the AWG7102 offers users am unprecedented level of testing flexibility.

The AWG7000 is the only AWG fast enough for high speed serial data test with up to 20Gsample/s and the ability to generate data streams including imperfections such as noise and jitter for datarates up to 10Gbit/s.

With two analogue channels and four marker outputs, the AWG7000 is capable of generating mixed-signal waveforms to provide for analogue signals and digital control channels.

For serial data, the high sample rate of the AWG7000 enables developers to create pre- and de-emphasis or multilevel signals such as four PAM (pulse amplitude modulation) without having to work with cumbersome external components and without wasting multiple output channels.