Microwave Journal
Next Generation 16-Bit Digitizers

Next Generation 16-Bit Digitizers

January 12, 2018

Over the years numerous customers have incorporated digitizers into their applications, their research setups, even their own products as original equipment manufacturer (OEM) components. While the general design concept is still a perfect fit for many applications, the technical realization is nowadays no longer state-of-the-art. Components are discontinued, technology has evolved and customers demand improving the hardware.

To adapt to current and future requirements, Spectrum Instrumentation is addressing these issues with the introduction of a newly designed digitizer card series. It consists of the new M2p platform board, which will be the PCI Express (PCIe) base for all future products from Spectrum. The first analog module series available for the M2p platform is the new 59xx module family, which consists of four different speed options of 20, 40, 80 or 125 MSPS and the choices of 1, 2, 4 or 8 channels. This creates 16 different digitizer products, and all cards can be switched by software between single-ended and differential inputs. These products will be the heart of a new mid-range digitizer series, designed to cover signal frequencies from 1 to 60 MHz.

Figure 1

Figure 1 The digitizer front-end amplifier can be switched between single-ended or true differential operation.


The existing cards in Spectrum’s M2i and M3i series comply with PCIe specifications; however, such full size, 312 mm cards are being sidelined by system vendors scaling down systems to a smaller footprint. With the M2p platform, even the smallest and compact PC system can be equipped with high performance measurement hardware—as long as the systems offer full height slots and reasonable cooling. Only 167 mm long, the new half length PCIe card format saves space, enabling it to fit into much smaller PC systems than before—perfect for compact OEM solutions—yet it offers more features than previously available. Each channel has a separate analog-to-digital converter and a fully individual programmable input amplifier with ranges between ±200 mV and ±10 V, programmable input offset for unipolar measurements, programmable input termination of 50 Ω and 1 MΩ and an integrated calibration circuit (see Figure 1). Models are available with up to eight single-ended and up to four differential channels.

Figure 2

Figure 2 The Star-Hub module enables systems with up to 128 channels.

The interface is PCI Express with four lanes, reaching a continuous streaming speed of more than 600 Mbps, or more than 75 MSPS continuous streaming for four channels. This extends the large on-board memory of 1 GB and enables applications that need continuous data storage or fast online calculations. Intelligent acquisition modes are incorporated in the FPGA: multiple recoding for segmented acquisition, gated sampling for time specific acquisition and ABA (dual time base) for a combination of half digitizer and flow chart recorder in one instrument. All modes can be combined with trigger time stamping. The combination of fast and slow continuous acquisition matches nearly every application demand. The versatile and proven piggyback module, called Star-Hub, (see Figure 2) allows systems to be created with up to 128 channels, all sharing a common clock and trigger, in one single chassis. For synchronization with external equipment, clock and trigger inputs and outputs are standard. For even more flexibility, four individually programmable connectors are available on the front plate that offer additional trigger inputs, status outputs, synchronous digital input lines, asynchronous I/O or a reference clock input for an integrated time stamping unit.


The new card is based on Spectrum’s general driver application programming interface (API) that was introduced in 2006; more than 400 different products now share this common driver library, allowing easy switching from slow to fast products and combining PCIe, PXIe or Ethernet/LXI products with one common software interface. A complete software development kit (SDK) based on Windows and Linux is included standard. Also, drivers and examples for nearly every programming language are included, leaving the decision of the preferred programming interface to the customer. The current SDK includes C, C++, C#, Delphi, VB.NET, J#, Python, Java, LabVIEW, MATLAB and LabWindows/CVI.

Within the 1 to 60 MHz range, the new units smoothly replace the company’s current 12-, 14- and 16-bit models, giving existing users an easy upgrade path with many technical advantages. As such, the applications for these new products include ultrasound, laser, LiDAR, radar, automotive and “big physics” experiments. All units are shipped factory tested and include a base version of Spectrum’s SBench 6 software for control, display, storage, analysis and reporting. The professional license of the software adds full support of all acquisition modes, a large number of calculations and new displays, project control and reporting. Like all the company’s digitizers, the new series has a five year warranty, with lifetime software and firmware updates and the company’s SDKs offered for free.




Spectrum Instrumentation GmbH
Grosshansdorf, Germany

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