Sigma Designs this week introduced the idea of taking the set top away from being on top of the TV, and produced a reference design and a new chip that will allow you instead to plug it straight into the wall, neatly out of sight. The reference design relies on the new SMP8670 media processor, and comes with built in Z-Wave control technology for RF based remote controls and the new Clearpath capability that Sigma describes as MIMO, which uses all three cables in a home power grid, to bring up the capability of powerline by two or three times the throughput. Michael Weissman, vice president of corporate marketing for Sigma Designs talked us through the new reference design which…