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27-10-2008
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Special colloquium: LOW-NOISE, HIGH DYNAMIC RANGE DIGITAL RECEIVER/SPECTROMETER FOR RADIO ASTRONOMY APPLICATIONS

Submitter: Marianna Ivashina
Description: Prof. Dmytro Vavriv from the Institute of Radio Astronomy of the National Academy of Science of Ukraine (Kharkov) will visit ASTRON on October 27th for the purpose of an invited colloquium.

In his presentation, he will talk about a recently developed digital receiver which is used at the Decameter radio telescope UTR-2, Kharkov, Ukraine. This receiver is shown in the figure above. It consists of two parts: an ADC module and a DSP board connected via a 5Gbit/sec serial data link. The DSP board is produced as a PCI card which supports the PCI-X64/66 standard interface. Different modes of signal processing are realized in the receiver by using the FPGA and the signal processor capabilities.

The ADC module is manufactured as a separate block in order to avoid interference from the DSP board and the PC. A high SFDR value of 115 dBc, a low noise floor of 120 dBFS, and a high SNR (dynamic range) of 74 dBFS have been achieved. A real time, half-overlapped FFT calculation and spectral averaging are carried out in the FPGA of the DSP board. The FFT is performed for 16384 points of a real signal (carrier) what provides 8192 frequency channels.

In addition to spectrum calculating modes, the DSP board can operate in a waveform mode. In this mode, it is possible to transfer data continuously with the rate of 260 Mbyte/sec via the PCI-X64/66 interface, and store them on the HDDs organized as a RAID-0 system.

The receiver has perfect linearity, a calibration option, and a capability for accurately computing correlations for beam-forming when used in multi-beam radio telescopes. Finally, the low cost of the receiver is determined by the usage of COTS components and original software solutions.
Copyright: Institute of Radio Astronomy of the National Academy of Sciences of Ukraine
 
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