Ultra-fast data-acquisition digitiser platform

November 18, 2013 // By Graham Prophet
German T&M company Spectrum has announced its first product in what will be a family of systems based on its ultra-fast, modular M4i platform and will, the company says, set standards for data acquisition and transfer speeds.

Spectrum designed the platform to meet the growing need for increased streaming bandwidth and higher sampling rates and is up to 16 times faster than previous models. Acquisition data is stored in a 4 GByte on-board buffer and can be read out at more than 3 GByte/sec through the PCI Express x8 Gen2 interface. The ¾ card length plug-in cards are compatible to Gen1 and Gen3 and need a PCI Express slot with 8 or 16 physical lanes.

The first model released using the platform - the M4i.4451-x8 - comes with four channels and 500 Msamples/sec synchronous sampling speed at 14 bit ADC resolution. A smaller version with two channels and 500 Msamples/sec is also available. Both versions have a signal bandwidth of 250 MHz.

To optimise data storage and bus transfer, repetitive signals can be stored into separate segments using Multiple Recording mode while transferring data in parallel. The M4i card is already equipped with different acquisition modes such as single-shot, 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. The time-stamp clock can either be based on the internal clock circuit or an externally fed-in time reference signal.

The four (or two) input channels are completely separate and have one monolithic ADC per channel, as well as their own high precision pre-amplifier. Each amplifier can be configured separately by software. Software can select one of six input ranges (±200 mV up to ±10V), 50 Ohm or 1 MOhm input impedance and AC or DC coupling. A bandwidth filter can be activated which suppresses high frequency noise signals.


The M4i cards have a trigger engine that can combine the two external trigger inputs with channel trigger of each channel by a logical OR or AND. The channel trigger detection can be programmed for edge,