Building the High Speed Data Acquisition System
Hybrid DSP assists clients in building high performance data acquisition front ends and if necessary their connection to storage devices such as SAS or the Hybrid DSP Distributed High Speed Data Recorder / Player (DHSDR). Possible front ends components are shown below and can be incorporated into many cPCI, cPCI-Express, PCI-X, PCI-Express systems with optional storage.
There are many advantages to separating the data acquisition system from the storage and control components. Optical fibre between I/O devices (digitizers and waveform generators) allows these to be placed more than 150 meters away from the storage or processing units:
- Position digitizers closer to source signals
- Shorter analogue cabling
- Large storage devices kept out of way
- Storage devices can be on central network
- Easier to control EMC interference
- Stand-alone hostless sensors
- System is controllable from office
The Problem of Data Throughput
High speed digitizers have been around for a long time, the problem occurs when you want to sample fast and in large or continuous bursts resulting in data throughput issues. The PCI bus was shared and its performance unpredictable. PCI-X promises well with its point to point transfers but motherboard architectures and complexity of multi-threaded software and operating system behaviour make this also complex. By using optical fibre connections directly from digitizers to the storage device we by-pass the PCI / PC bottleneck. When you do need to go via the host PC then Hybrid DSP are the experts in motherboard selection and software design for achieving maximum throughput: overlapped I/O, client - server distributed architectures, device drivers, full-duplex I/O, multi-processor / multi-thread optimization, file systems, file formats, etc.
Data Acquisition Solutions Product Brief (pdf)