[Mike Field] took what he had learned with a few past projects and combined them to make this FPGA-based SPDIF audio pass-through. In order to get the SPDIF signal ready for the FPGA he needed a few components to use for level conversion. Once everything was connected he used a first in first out (FIFO) buffer to ensure that the outgoing bitrate is the same as the input, while still allowing enough time for the FPGA to do some digital manipulation.
This reminds us of the NeTV, which is an HDMI pass-through device. That one allows you to overlay your own video information to any TV that has an HDMI port. This would allow you patch into any audio system that’s using SPDIF, letting you inject your own audio, such as a paging system in a public lobby, or the ringing of a phone when you get a call, or to create your own sounds.
We like his overhand knot cable management system to keep those jumper wires from becoming too much of a mess on the breadboard.