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 <[email protected]> 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 <[email protected]> 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 "[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/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 "[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/CAGHS_vEP2eAHz3yA%3D-vinUrq1dmNdFDnbQf%3DKdVKztb0H2HjdA%40mail.gmail.com.
