When the AXIe standard was announced, a common question was, “why do we need another standard?” The response was typically a technical summary of module sizes, bus structures, power supplies and cooling systems. Yes, you could imagine the increased density due to the deeper profile and robust cooling system. You could also imagine clever uses of the 62 lane wide local bus. But unless someone actually offers real products that exploit these features, it remains an unproven hypothesis.
Back to basics. The core specifications of any digitizer are its speed (sampling rate and bandwidth), its resolution (bits, effective bits, SFDR), number of channels, and it’s memory depth. Guzik has taken an 8-bit A/D converter architecture that supports an aggregated 40Gs/s (that’s right, 40 Gigasamples per second) on a blade, and produced multiple derivatives of it:
- 1 channel at 40Gs/s – 13Ghz BW
- 2 channels at 20Gs/s – 8Ghz BW
- 4 channels at 10Gs/s – 4Ghz BW
There’s also a 3 channel version with improved bandwidth. These are very impressive specifications, but two other things particularly stand out. Each blade can have up to 64 GByte of memory. Yikes! That’s a G, not a K or an M. Try to put that much 40Gs memory onto a single PC board, and you will realize what AXIe can bring to the table. If that is not enough, Guzik took advantage of AXIe’s high-speed local bus, and is able to stream data at full bandwidth to additional memory cards or digital processors.
I spoke with Lauri Viitas, Marketing Manager at Guzik, about the product. He claims that even when loaded up with memory, the AXIe platform delivers double the density of the other form factors, such as PXI. So I tested the hypothesis. The 20Gs and 40Gs products have no equivalent in PXI, but the 10Gs/s does. In PXI, a user can concentrate 10 such channels into a 4U PXI chassis. In AXIe, a 4U chassis hosts 5 slots, each with 4 channels. That’s 20 channels in the same rack space, or a 2 to 1 density improvement.
This is where both form factors bring their particular strengths. PXI products generally offer superior granularity and can be mixed and matched with other PXI products. AXIe products offer advantages of pure density and performance. The application will drive the choice of form factors.
Speaking of applications, where does the Guzik product fit? Guzik has a rich background in disk drive testing, so I assume this is a good match. The ADC 6000 family will also find a home where the density of a large number of synchronized channels is critical. “Big Physics” comes to mind, as well as many aerospace and defense applications.
The AXIe Consortium has positioned AXIe as the big brother to PXI since it’s creation. Kudos to Guzik for delivering a compelling proof point.