Dynamic RFI measurement systems on a ROACH-2 platform ICEAA-IEEE APWC-EMS

We describe developments in a radio frequency interference (RFI) detection instrument dubbed RATTY 2. With uncertain RFI environments in mind, the system is hardware and software reconfigurable, functioning either as a spectrometer or a transient-signal analyser. RATTY 2 is equipped with a 900 MHz bandwidth, 10-bit, non-interleaved analogue-digital converter (ADC) and the data is processed on a Reconfigurable Open Architecture Computer Hardware 2 (ROACH) platform. A computer is used for post-processing dynamically-stored data. Two different strategies were followed in designing the RF front-end systems for signal conditioning prior to digitisation: 1) a single mixer, down-converting topology, and 2) a multiple Nyquist-zone sampling configuration. The two systems are evaluated and compared in this paper.