Hi dan， Thank you very much for telling me this.
I have a question: My current project consists of 96 dual-polarized antennas, so there are 192 signal inputs, and each F engine has 32 inputs. Therefore, I plan to use 6 ROACH2 (6 F-engines), but only 8,4,2,1 is given in CTMODE. Can I design the model of 6 F-engines by the same way? Cheers, Wang 在2022年11月27日星期日 UTC+8 04:29:19<danseti> 写道： > > > hi wang, > > a bit more about the corner turner - > you probably know about this, but just in case: > > for an FX correlator, there's an F engine for each antenna and each > polarization to break the time domain signal into frequency channels. > for large antenna arrays or large bandwidths, the correlation is too much > computation and too high a data rate for a single X engine, > so this real time correlation computation must be broken up into several X > engines (several CPU's, or GPU's, or FPGA's). > > in an FX correlator, this computation is sliced up by frequency - > different sub-bands are sent to different X engines. > to compute the correlation on all the antennas, each X engine requires > data from all the antennas and polarizations, > but that X engine only needs data from a subset of the frequency channels. > > so the job of the corner-turner/transpose/data-reorder is to take the full > bandwidth data from all the antennas, and break it up into subbands, > and then send each subband to a different Xengine. > > best wishes, > > dan > > > > On Sat, Nov 26, 2022 at 12:01 AM Wang <sandang...@gmail.com> wrote: > >> Thank you very much dan. >> cheers, >> Wang >> >> >> 在2022年11月26日星期六 UTC+8 12:31:58<danseti> 写道： >> >>> >>> >>> hi wang, >>> >>> i can only answer two of your questions: >>> >>> 1) >>> the "corner turner" is also called a "data re-order" or a "matrix >>> transpose". >>> it's job is to change antenna ordered data to frequency ordered data. >>> >>> 2) >>> "miriad" is an open source data reduction software package for radio >>> antenna arrays. >>> e.g. it does post processing convert the data from a correlator into a >>> spectral image. >>> >>> best wishes, >>> >>> dan >>> >>> >>> On Fri, Nov 25, 2022 at 9:37 AM Wang <sandang...@gmail.com> wrote: >>> >>>> Hi all， >>>> >>>> I am studying the design of PAPER Correlator. >>>> PAPER Correlator Netcfg - Casper (berkeley.edu) >>>> <https://casper.astro.berkeley.edu/wiki/PAPER_Correlator_Netcfg> >>>> There are some questions about Corner Turner Mode(CTMODE) and MIRIAD >>>> Channel Mapping. >>>> >>>> 8 F engines(CTMODE):The 256 inputs by 1024 channels are presented to >>>> the X engines as exactly that. >>>> 4 F engines(CTMODE):The 128 inputs by 1024 channels are presented to >>>> the X engines as 256 inputs by 512 channels. >>>> ······ >>>> I know that each F engine has 32 inputs, so 8 for 256 and 4 for 128. >>>> But in 'X engine' I don't understand the relationship between input and >>>> channel. >>>> >>>> And，I have a silly question, why is 'Corner Turner' called that? >>>> >>>> The last part is "MIRIAD Channel Mapping". >>>> I don't understand the meaning of the abbreviation (if it is an >>>> abbreviation). >>>> Can I get this part by typing the command line? >>>> >>>> I'd appreciate it if someone could help me with that! >>>> >>>> BW！ >>>> Wang >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "cas...@lists.berkeley.edu" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to casper+un...@lists.berkeley.edu. >>>> To view this discussion on the web visit >>>> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/966891fe-31ae-4280-a4e4-18a71f94a12cn%40lists.berkeley.edu >>>> >>>> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/966891fe-31ae-4280-a4e4-18a71f94a12cn%40lists.berkeley.edu?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/b432e507-f11d-4608-baff-d0999378165fn%40lists.berkeley.edu.
