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Dtacq2weraOld

  % dtacq2wera

  NCHAN=16;       % the number of dtacq A/D channel PAIRS
  IQ=2;           % number of channels to make pair
  OVER=2;         % the oversampling rate
  NANT=8;         % the WERA number of antennas, remaining channels set to 0
  MT=1984;        % the number of WERA samples/chirp
  NCHIRP=2048;    % the number of chirps
  SKIP=1;         % we'll have to SKIP chirps
  SHIFT=6;        % number of bits to loose when converting 32->16 bit

  % read a binary dtacq file over exact number of chirps
  % raw dtacq data: NCHIRP+SKIP of MT*OVER of NCHAN A/D channel pairs,
  % each containing IQ channels of 4 bytes (long)
  % file acquired with SKIP>>1

  f=fopen(filein,'r','ieee-le');
  raw=fread(f,Inf,'int32=>int32');
  fclose(f);

  N=length(raw)                   % the raw number of samples
  NFRAM=floor(N/(NCHAN*IQ*OVER))  % the number of intact frames
  N=NFRAM*NCHAN*IQ*OVER           % the cleaned number of samples

  data=reshape(raw(1:N),NCHAN*IQ,NFRAM*OVER);
  clear raw;

  % remap data channels to dtacq indices
  % root@acq164_061 ~ #cat /dev/dtacq/channel_mapping
  % checked - after mapping channels 17-32 are correctly empty
  % assume mapping is correct w.r.t I/Q

  map=reshape([ 1  0 2  4 3  8 4 12 5  1 6  5 7  9 8 13 9  2 10  6 11 10 12 14 13  3 14  7 15 11 16 15 17 19 18 23 19 27 20 31 21 18 22 22 23 26 24 30 25 17 26 21 27 25 28 29 29 16 30 20 31 24 32 28],2,32)';
  map(:,2)=map(:,2)+1;

  mdata(squeeze(map(:,2)),:)=data(squeeze(map(:,1)),:);
  clear data;

  % average oversampling and decimate; shift to int16 range (/256)
  % I find that the /256 is way too much. After /256, max/min is 10000 but
  % std is only 500. Let/s divide by only 64 (6 bits SNR gained).
  % ENOB appears to be around 19 bits. Get rid of 6 bits

  sdata=zeros(NCHAN*IQ,NFRAM);
  for i=1:NCHAN*IQ
          sdata(i,1:NFRAM)=(mdata(i,1:OVER:OVER*NFRAM-1)+mdata(i,2:OVER:OVER*NFRAM))/2^(SHIFT+1);
          end
  %clear mdata;

  % clip overrange if any

  sdata(find(sdata>2^15-1))=2^15-1;
  sdata(find(sdata<-2^15+1))=-2^15+1;

  % 37 bad samples before first chirp

  sdata(:,1:37)=[];

  % write binary wera data
  % .RAW format: NCHIRP of NANT antennas, each containing
  % MT samples of IQ of 2 bytes (short)
  % CAUTION! looking at Yves Barbin read function suggest that
  % the indices order is NANT,MT,IQ,NCHIRP
  % with the code below,  I can read and
  % rewrite out and see Bragg lines with a Zambales .RAW file
  % skip first chirp
  % CAUTION! this is correct only for an 8-antenna 16-channel system

  wera=int16(zeros(IQ,MT,NANT,NCHIRP));
  for ichirp=2:NCHIRP+1
    for iant=1:NANT
      for imt=1:MT
        for iiq=1:IQ
  % verified by disconnecting: I 1...8 followed by Q 1...8
  %       wera(iiq,imt,iant,ichirp-1)=int16(sdata(iant+(iiq-1)*NANT,(ichirp-1)*MT+imt));
  % I-Q swapped? try below
          wera(IQ-iiq+1,imt,iant,ichirp-1)=int16(sdata(iant+(iiq-1)*NANT,(ichirp-1)*MT+imt));
        end
      end
    end
  end

  % output the binary part of a wera .RAW file

  f=fopen(fileout,'w','ieee-le');
  fwrite(f,wera,'int16');
  fclose(f);
  clear wera

  % save sdata, only for debugging, slow, do not save if not needed
  clear sdata;
  % save mdata
  save