> > If we are OK with losing the back-compatibility with previous designs, we > can think about using high-speed connectors e.g. SAMTEC QRM8, which are > designed for this sort of thing.
How about this solution: we use an inexpensive high-speed board-edge connector (Samtec HSEC8-DV: http://www.samtec.com/technical-specifications/default.aspx?SeriesMaster=HSEC8-DV). The new DDS boards would then have gold fingers on the edges and just plug in, much in the same way one plugs in a RAM DIMM module in a computer, potentially with board locks as is used for DIMMs. This connector should have plenty of bandwidth for the rise times we are discussing (spec'ed to 10.5 GHz for differential signals). We get a connector with 74 or 80 pins, which is enough to send in all the signals we would want plus some to spare. Then, we can make a simple, very short adapter board with a 2mm pin header on one side and fingers on the other side, wired such that we could plug any legacy DDS cards with 2mm connectors into the new FMC backplane via the adapter board. This board would be very inexpensive to build dozens or hundreds of, and the 2mm pin header could be stuffed by hand as needed. Obviously any legacy DDS cards would not be able to take advantage of the new features, e.g. syncing, that we are planning, but this adapter board would enable them to be used if desired for some reason. Thus we solve the back-compatibility problem as well as the connector speed/edge time problem. _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
