Ultra Wideband ADCs and FPGA Technology for Processing RF Telescope Data
October 16, 2018Download PDF
Radio Frequency (RF) telescopes are different than standard optical telescopes as they amplify radio frequencies in the GHz domain rather than light waves. As the front-end of these telescopes are continuously improved, it is important that the back-end processing be updated to take advantage of the latest advancements in technology. For one observatory, processing RF signal data using legacy systems proved to be a challenge.
Dated systems often make it difficult to generate timely and efficient results. Today, to perform spectroscopic analysis, or measure the frequency spectrum of incoming data, some scientists and engineers are exploring a more modern method utilizing multi-GHz analog-to-digital-converters (ADCs) coupled with Field Programmable Gate Array (FPGA). With the wider bandwidths now available in silicon ADCs, the front-end of the RF telescope can be used to filter large swaths of bandwidth with a single down conversion stage, and any further processing within that band can be done digitally within the FPGA. For the observatory, this required just a few front-end RF channels to simplify the analog design. Even with this simplification, there was still the challenge of processing a 4 GHz input signal that was being received from the RF telescope and perform spectrometry on the incoming data. To process a 4 GHz signal, the data needed to be sampled with at least an 8 GHz clock and preferably a bit faster. Few products in the market can do that today. Another challenge involved improving image rejection using a digital signal-processing algorithm. This required a big FPGA that had enough resources to implement a large Fast Fourier Transform (FFT) algorithm as well as the IO bandwidth to handle the tremendous amount of data being received.
The decision to be made was, could the legacy system be updated using modern FPGA technology? The choice was easy. After confirming that a product manufactured by Curtiss-Wright could handle such a wide frequency and keep up with incoming data, the CHAMP-WB-A25G was selected for the task.
The CHAMP-WB-A25G’s FPGA with its two 12.5 GHz ADCs and sample and hold device proved to be a perfect fit for the customers application. With the improved, much smaller and more reliable system, the customer is able to capture results that are more accurate.
Read about the solution Curtiss-Wright developed and the results achieved in our case study - download the 'Using Ultra Wideband ADCs and FPGA Technology for Processing RF Telescope Data' case study here.