Speaker
Description
ASTRON is developing technology for 'large-N, small-D' radio telescopes, i.e. systems having many, small, low-cost antennas. To reduce the receiver cost, we are investigating various technologies, such as non-cryogenic ultra-low noise frontends, simple RF chains with direct sampling receivers and white-rabbit timing.
An L-band technology demonstrator, using one of the Westerbork Synthesis Radio Telescope (WSRT) dishes, is currently being developed to test these new technologies. The demonstrator aims to achieve a system noise temperature of 30 K over a 1 GHz bandwidth in the L-band, which is a crowded RFI environment.
The frontend builds upon advances in low-noise transistors operating at ambient temperatures. A new design technique makes it possible to integrated the low-noise amplifier into the feed and optimise them together for minimum noise. The first such active feed will be presented, with a measured receiver noise temperature of around 15 K at room temperature.
Following amplification and filtering, an ethernet receiver is used to directly sampled the RF signals (at 14 bits per sample) and transport them via optical fiber ethernet. Timing is distributed over the optical fiber using white-rabbit technology. A first 100MHz bandwidth ethernet receiver with integrated white-rabbit timing has been produced and a new 1 GHz bandwidth receiver is currently under developed.
