High-precision PCIe 625 Msample/sec, 16-bit arbitrary generators

June 17, 2015 // By Graham Prophet
Spectrum (Grosshansdorf, Germany) has added three M4i series arbitrary waveform generators (AWGs) with one, two or four channels with each channel capable of outputting signals at rates of up to 625 Msamples/sec with 16 bit amplitude resolution.

TheseAWGs can generate signals up to 200 MHz with accuracy and fidelity. Based on Spectrum's M4i series PCI Express (PCIe) platform the products are much smaller than conventional instruments and can be used in most modern PCs. Install the AWG cards into a vacant PCIe x8 or x16 slot, install the driver, load Spectrum's software and start generating waveforms. The AWG's are fully programmable and work with Spectrum's own SBench 6 control software as well as third party software tools such as LabVIEW, LabWindows and MATLAB.

To allow the generation of long and complex waveforms the AWGs include 2 Gsamples of on-board memory and a number of operating modes such as Single-Shot, Loop, FIFO, Gating and Sequence Replay. The Sequence Replay mode allows the unit to store different waveform segments in memory and concatenate and loop them in a sequence. The user can switch between stored waveforms by software command or overload waveforms in run-time.

In FIFO mode the cards use an ultra-fast PCIe x8 Gen2 interface to stream data continuously from the PC memory to the AWG at speeds in excess of 1.5 GB/sec. If two or four channels are used the outputs are fully synchronised and share a common clock to ensure minimal phase error. If more channels are needed then up to 8 cards can be connected together with Spectrum's Star-Hub clock and trigger system. Star-Hub enables instruments with up to 32 fully synchronous channels to be created.

Designed to output signals that simulate those found in the real world the AWG's deliver programmable output levels from ±200 mV to ±5V into high-impedance (resulting in ±100 mV up to ±2.5V into 50Ω termination). Using 16 bit digital to analogue conversion the AWGs also allow fine signal details to be generated. They deliver dynamic performance both in signal-to-noise (SNR) and spurious free dynamic range (SFDR).

Each channel is clocked using a precision phase locked loop (PLL) control system