Thanks Homin, that's a nice find! I have checked the MeerKAT designs, and our convert latencies are all set to zero, and can verify that the operation is correct in this case. The xeng's dual-pol-cmac primitive also has an embedded cmult with latency set to zero. If it pulls a new cmult out the library, however, it gets a latency of one.
The Xeng init script doesn't try to set these parameters, from what I can tell. It looks like the cmult block's defaults must have changed at some point, from zero to one, and the xeng design still assumes a latency of zero. An appeal to all CASPERites: whenever committing new features or changes to a block, please ensure that the default behaviour matches that of the original block. Jason > On 08 Apr 2020, at 05:30, Homin Jiang <[email protected]> wrote: > > Dear all: > > Hope that you are well all. > Recently we have an issue about correlation that motivates me to dig > in the X engine block. Found that it might be a bug in the X engine > block. > I compare the current X engine with the one a couple years ago, "mdl" > era. The difference is that there is one more delay in the current X > engine. The older one has no problem. They are here: > ----------------------------------------------------------------------------------- > Xengine -> auto_tap, baseline_tap1, baseline_tap2, ... baseline_tapn > -> dual_pol_cmac->cmac2, cmac3, cmac4-> cmult -> latency -> change > "convert latency" from 1 to 0. > -------------------------------------------------------------------------------------- > If you used directly, the output will not be exactly correct. > > best regards > homin jiang > > -- > You received this message because you are subscribed to the Google Groups > "[email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAGbeiKjwbDbi3C3XFLbgzsiZ4bKvcD1jvgP7Z5TbLrDc-PFWUw%40mail.gmail.com. -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/DC3C5C5E-2B97-4BD1-95D9-0673D89D80EC%40ska.ac.za.
