Re: [casper] Roach2/channelization question

[Gerry Harp]

Hi  Dan Your numbers look somehow backwards. Did you mean: 32 inputs at 8K 16 at 4K 8 at 2K 4 at 1K? Presumably, by narrowing the input bandwidth could permit proportionally smaller channels at the output? So at 2.5 MHz input one could do 1 Hz channels? Trying and compiling is the right thing to do. Hopefully we can arrange to do this pretty soon. Gerry On 8/24/2012 8:55 AM, Dan Werthimer wrote: hi john,   to get a real number, it would be best to compile the design . you can re-compile zaki's octal F engine designed for roach I (8 inputs at 250 Msps), or Hong's F engine (32 inputs at 250 Msps, designed for roach II).   rough guess:  you can get 32 analog inputs at 1K channels, or 16 analog inputs at 2K channels, or 8 analog inputs at 4K channels, or 4 analog inputs at 8K channels.   best wishes,   dan   On Fri, Aug 24, 2012 at 7:54 AM, Jon Richards <jricha...@seti.org> wrote: All, I need some advice. We are looking into developing an FX correlator using the Roach2 s as the "F" and GPUs as the "X". We will have 4 inputs to the Roach2 ADCs, at 250Msamples/sec, 8Gb/sec flowing out to the X boards. How many channels should the Roach2 be able to process? How would I guestimate that? Any ideas appreciated! Thanks, Jon Richards -- ---------------------- Gerald R. Harp, Ph.D. Director, Center for SETI Research SETI Institute