The FPGA-based continuous FFT tune measurement system for the LHC and its test at the CERN SPS

A base band tune (BBQ) measurement system has recently been developed at CERN based on a high- sensitivity direct-diode detection technique followed by a high resolution FFT algorithm implemented in an FPGA. The FPGA based digital processing allows the acquisition of continuous real-time spectra with 32-bit resolution, while a digital frequency synthesiser (DFS) can provide acquisition synchronised chirp excitation. All the implemented algorithms support dynamic reconfiguration of processing and excitation parameters. Results from both laboratory measurements and tests performed with beam at the CERN SPS will be presented.