On February 18, 2016 at 10:21, Fred Harding said...
Murideo makes a 4k signal generator. I don't think you'll be excited by the price, however...
What Fred said:
This is a great unit (although not cheap) at $2500, it will generate a full 18 Gbps, 4K/60, 4:4:4 or 4K/60, 4:2:0 HDR signal, as well as pretty much any other resolution. They also have (coming in about 6 weeks) a signal analyzer.