* Software Radio
* LIGO viewer
* DAQ system
* About me
The data acqusition system pictured above can acquire data with 24-bit resolution at 50 kS/s and output high precision (16 and 20 bit) voltages. It was created with mostly Open Source software, with the exception of two components: Xilinx WebKit and Digilent Adept, both of which are freely available, but closed source.
Why not use ready-made commercial cards ?
- There is often a large lag between release of new ADCs and DACs from manufacturers and when they become available in commercial cards.
- High end cards are usually very expensive.
- There is usually no access to FPGA and no way to enforce particular timing regimes (i.e. you cannot sync your digital circuits to a GPS module or other custom clock)
- A data sheet for a TI or Analog ADC has exhaustive documation of device performance. A commercial ADC card often says that it is "16-bit" and, maybe, provides absolute maximum voltages.
- There is a disturbing tendency of many companies to force their custom software on users, which interferes with application in real-life situations.
Advantages of custom DAQ system
- You have complete control over FPGA programming:
- Input and use custom clocks
- Create and output custom clocks, use them to annotate acquired samples.
- Implement control circuits directly in FPGA.
- Use Ethernet to transfer data to main analysis computer.
- Use ready made evaluation boards or make your own for latest ADC/DAC chips from any manufacturer.
Features of this daq system
- Accepts 24-bit 50 kS/s TI ADC modules.
- Accepts 16 and 20 bit TI DAC modules.
- Interfaces to main data acquisition computer via 100 Mbit ethernet cable.
- Design made mostly with Open Source software, with the exception of FPGA programming tools (Xilinx Webkit and Digilent Adept).
- Part cost less than $1000 for a single unit.
Papers using this daq system
- A high precision, compact electromechanical ground rotation sensor, V.Dergachev, R.DeSalvo, M.Asador, A.Bhawal, P.Gong, C.Kim, A.Lottarini, Y.Minenkov, C.Murphy, A.O'Toole, F.E.Pena Arellano, A.V.Rodionov, M.Shaner, E.Sobacchi, RSI 85, 054502 2014)
- Design and Initial Characterization of a Compact, Ultra High Vacuum Compatible, Low Frequency, Tilt Accelerometer,
A. O'Toole, F.E.Pena Arellano, A.V.Rodionov, M.Shaner, E.Sobacchi, V.Dergachev, R.DeSalvo, M.Asadoor, A.Bhawal, P.Gong, C.Kim, A.Lottarini, Y.Minenkov, C.Murphy, accepted to RSI.
- Wiener filtering with a seismic underground array at the Sanford Underground Research Facility, Michael Coughlin, Jan Harms, Nelson Christensen, Vladimir Dergachev, Riccardo DeSalvo, Shivaraj Kandhasamy, Vuk Mandic