Toward 64 Gbps wideband digital backend design for the Event Horizon Telescope

A broad international collaboration is building the Event Horizon Telescope (EHT). The aim is to test Einstein's theory of General Relativity (GR) in one of the very few places it could break down: the strong gravity regime right at the edge of a black hole. The EHT is an earthsize VLBI array operating at the shortest radio wavelengths that has achieved unprecedented angular resolution of a few tens of μarcseconds. For nearby supermassive black holes (SMBH) this size scale is comparable to the Schwarzschild Radius, and emission in the strong GR regime at the edge of the event horizon can be directly observed.