  The core architecture, tests in the lab and first results of a Fast Fourier
Transform (FFT) spectrometer are described. It is based on a commercially
available fast digital sampler (AC240) with an on-board Field Programmable Gate
Array (FPGA). The spectrometer works continuously and has a remarkable total
bandwidth of 1 GHz, resolved into 16384 channels. The data is sampled with 8
bits, yielding a dynamic range of 48 dB. An Allan time of more than 2000 s and
an SFDR of 37 dB were measured. First light observations with the KOSMA
telescope show a perfect spectrum without internal or external spurious
signals.
