New high-speed PXI Express digitizer family

13-06-2016 | Spectrum | Subs & Systems

Spectrum has released its first high-speed digitizer product line based on the popular PXIe (PXI Express) modular instrumentation standard. The M4x.44xx series consists of six new products, each packaged in a dual-width 3U module and incorporating a four lane PCI Express Generation 2 interface. The high-performance interface allows data transfer speeds in excess of 1.7GB/s, making the cards ideal for use in today's fastest PXIe mainframe systems.

The digitizers include versions with two and four fully synchronous channels and they come with resolutions of either 14 bits, for sampling at rates up to 500 MS/s, or 16 bits, for sampling at rates up to 130 or 250MS/s. With analog bandwidth up to 250 MHz, the digitizers are suited to use in ATE systems where electronic signals in the 1 to 200MHz range need to be acquired and measured with the best possible speed and precision.

Typical applications include semiconductor and component testing, radar, wireless communications, medical science, automotive, power, physics, surveillance, aerospace and defence systems.

Designed so that they can be used with the widest range of signals the M4x.44xx series cards feature an oscilloscope style front-end. Each channel has its own separate monolithic ADC and low noise signal conditioning circuitry. Fully programmable, the cards provide six gain input ranges (±200mV up to ±10V), selectable input impedance of 50ohm or 1Oohm and AC or DC coupling. Furthermore, an internal bandwidth filter can be activated in situations where high frequency noise, that may mask signals, needs to be suppressed.

The flexible front-end circuitry is complimented by a powerful trigger system and versatile clock. The trigger source can be any of the input channels, either of the two external trigger inputs, any of the eight PXI trigger lines or the PXI star trigger. Trigger modes include positive or negative edge, both edges (window), software and rearm. In addition, logic triggering can be implemented based on the state of the channel and the external trigger inputs.

The clocking system of the digitizers is precise and advanced. The clock can be internally or externally generated (including as source the 100 MHz PXIe differential clock and the 10MHz PXI clock). It has a built-in 10 MHz reference and, if required, it can be synchronized with other reference sources. A fine-resolution mode is also available that allows clock rates to be selected with 1Hz resolution. The feature makes it possible to program the sampling rate of the digitizers to match that of other devices or to setup acquisitions for specialized input signal conditions.

All the digitizers come with a standard 4 GByte (2 Giga-Samples) of on-board acquisition memory. The large memory makes it easy to acquire long and complex signals. The capability is further expanded by a host of data acquisition and readout modes. These include single-shot capture (transient recording), streaming (FIFO), segmented (Multiple Recording), gated (Gated Sampling), or the combination of segmented acquisition of fast signals in parallel with slow continuous data recording (ABA mode). All trigger events can be time stamped, making it simple to know when they occurred and to determine the time between events.

With their low noise front-ends, high-resolution ADCs and accurate clocks, these PXIe digitizers deliver outstanding dynamic performance. For example, signal-to-noise ratios (SNR) are typically over 70dB, spurious free dynamic range (SFDR) is better than 90 dB, and total harmonic distortion (THD) is less than -70dB. The combination not only makes it possible to detect small signals on large ones but it also produces better measurement repeatability, precision and accuracy.

The new PXIe products are based on Spectrum's proven M4i line of standard PCIe products and combine the advanced features and signal quality of this series with the industrial standard of PXIe. The M4x products are two slots wide and fit into any PXIe chassis. Compared with the PCIe standard PXIe systems come with superior mechanical design, better connectors and a defined air flow for cooling. All these features make it an ideal platform for industrial and mobile applications including those found in aerospace and defence or transportation. As Spectrum's M4x platform is based on a modular concept, it will also allow the release of several new PXIe products within a short time - all programmed through a common software interface that is compatible to existing PCIe, PCI and LXI products.

Another advantage of sharing technology between platforms is that the new PXIe modules can immediately utilize the FPGA based firmware options that already exist for the PCIe cards. Block averaging and block statistics packages are available for high trigger rate applications that require hardware based processing functions. Block averaging can be used to reduce signal noise and improve measurement resolution while block statistics performs a peak detection process that yields a waveforms maximum, minimum and average values.

To control and operate the digitizers, Spectrum provides its powerful SBench 6 program. SBench 6 supports all the key functions of the digitizer as well as providing data display, storage, analysis and documentation. The program offers both oscilloscope and transient recording modes, including data streaming. A base version of SBench 6 is provided free of charge to enable out-of-the box operation of the digitizers.

Users who want to develop their own programs can use the proven Spectrum drivers (available for Windows and Linux), which are included in the delivery. A set of standard programming examples is provided to illustrate the cards main signal capture functions. Extensive support includes Visual C++, Borland C++, Gnu C++, LabVIEW, MATLAB, Visual Basic, VB.NET, C#, J# and Delphi code, says the company.

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