Cite? I'd be rather surprised. Sky are toying with 4k but I don't think they have any routine 4k broadcasts.
SD though? Some of the "lesser" channels are nearer 1 Mbps or below or were.
Which way is that meant to be read?
1) 1 Gbps is not fast enough for decent orgination. 2) 1 Gbps is too fast for distribution to the end user.SDI is what is used to link cameras to CCUs, CCUs to mixers/EVS, truck output to fibre/sat truck, seems to be a "broadcast signal" to me...