Electronics and SoftwareEngineering Innovation
AstroFFT: Astronomical Digital Spectrometer
||The AstroFFT Digital Spectrometer System is
designed to pick out coherent signals from large levels of
noise. One example of use is to survey the Galaxy searching
for maser emission from water both in star-forming regions
and in the circumstellar envelopes of late-type stars.
The system processes, in real time, multiple wide
bandwidth analogue signals from a radio telescope. The
system employs the Fast Fourier Transform (FFT) to
calculate the spectrum of the signals and integrates the
power of this spectrum over time.
The AstroFFT system consists of a network accessible host
containing multiple FFT processing engines. Each
processing engine has two, fast, analogue to digital
converters connected directly to one of the latest
generation of Field Programmable Gate Arrays (FPGA's). The
FFT, power and integration calculations are performed by
this FPGA. This novel architecture provides the high level
of performance required with the flexibility to modify or
use different processing algorithms.
- Network connected FFT processing
- Host system based on the Linux
operating system for reliability and flexibility.
- Real-time data capture and
- FPGA based re-configurable hardware
based on the Xilinx Vertex-E series chips for fast and
flexible signal processing.
- Parallel FFT, power and integration
algorithms in hardware.
- Multiple processing engines per
- Processing engines can be
interconnected with high speed connections.
- Alternative data processing
algorithms can be developed and downloaded to the
- GUI control application for
configuration and control.
- Remote control by remote software.
- Data stored on local disk accessible
via NFS, SMB, FTP or HTTP network protocols.
- Input signal: 2V p-p into 50
ohm on each channel.
- Input Clock: 50 MHz digital
clock input into 100 ohm.
- Internal 50MHz digital clock.
- Clock source selection with
- Anti-aliasing filters on each
channel: 6 pole elliptic filter, 1 KHz to 23 MHz +-1
- Two 50MHz 14 bit analogue to digital
samplers per processing engine.
- FFT Algorithm: 4096 point, 14 bit
with adaptive scaling in 82 micro seconds.
- Spectrum power Integrator: operates
in parallel with the FFT algorithm, 64 bit depth.
- Further integration on the host
using 64 bit floating point arithmetic.
- 10/100 baseT Ethernet network
- Standard algorithms: analogue data
capture, FFT processing, quadrature FFT processing.