A Field Programmable Gate Array Spectrometer for Radio Astronomy First Light at the Effelsberg 100-m Telescope

We describe the technological concept and the first-light re sults of a 1024-channel spectrometer based on field programmable gate array (FPGA) hardware. This spectrometer is the prototype for the seven beam L-band receiver to be installed at the Effelsberg 100-m telescope in autumn 2005. Using "of-the-shelf" hardware and software products, we designed and constructed an extremely flexible Fast-Fourier-Transf orm (FFT) spectrometer with unprecedented sensitivity and dynamic range, which can be considered prototypical for spectrometer development in future radio astronomy.