National Instruments Cabled PCI Express guide

Figure 3. Cabled PCI Express makes MXI Express 80X higher bandwidth than MXI-1

While bandwidth has dramatically increased, the costs of these links have decreased. Figure 4 shows how the price per bandwidth has dropped significantly over the last 15 years.

Figure 4: From $450/MB/s to $2.25/MB/s – Cabled PCI Express Helps Decrease Price per Bandwidth

MXI Express x1 for PXI chassis cut the cost per MB/s in half from $19/MB/s to $9/MB/s. MXI Express x4 for PXI Express chassis cut that further to $2.25/MB/s. The cost reductions show the power of adopting commercial technologies and ensure that PXI-based virtual instrumentation will continue to grow into more price sensitive applications.

Software-centric Synthetic and Virtual Instrumentation

Because cabled PCI Express was designed for box-to-box applications it can connect a PC to traditional instruments. As the trend for more software-centric instrumentation increases, the need for a high-speed connection to a host processor is even more important. The US Department of Defense, for example, has coined a term called synthetic instrumentation, to describe these software-centric systems. The DoD has created a forum called the Synthetic Instrument Working Group (SIWG) who’s role is to define standards for interoperability of synthetic instrument systems. The SIWG defines synthetic instruments (SI) as:

A reconfigurable system that links a series of elemental hardware and software components with standardized interfaces to generate signals or make measurements using numeric processing techniques.

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