Digital signal processing for radio astronomy
The application-specific integrated circuit (ASIC) for the digital spectrometer was developed within the EU-funded project ADSPRA (Advanced digital signal processing for radio astronomy applications). This ASIC has been fabricated using radiation-tolerant 65-nm complementary metal-oxide semiconductor technology. The ADSPRA chip integrates an analogue-to-digital converter, digital spectroscopy and spectral analysis functions. Specifically, the digital back end of the chip combines a polyphase filter bank and a fast Fourier transform together with a digital transmitter that serialises data and transmits it to an on-board computer. A test structure was used to support the detection of soft errors. Researchers used a field-programmable gate array board to evaluate the performance of signal processing algorithms and, generally, the behaviour of the chip's digital back end. The largely digital nature of the implementation promises reduced calibration requirements and enhanced stability compared to alternative approaches. Before the end of ADSPRA, digital design tools were also set up for the development of mixed-signal ASICs. Researchers are still working on revolutionising the development of signal processing instrumentation for the next generation of radio telescopes. Computational requirements will be far beyond the capabilities of general-purpose computing devices that have traditionally been the commodity solution.
Keywords
Signal processing, radio astronomy, digital spectrometer, ASIC, ADSPRA
