如何用Matlab处理.wfm格式的数据
从示波器中捕获的波形处理，此代码源于https://ww2.mathworks.cn/matlabcentral/fileexchange/14918-tektronix-wfm-file-reader
function:
1 function [out_descript, outdata, timedata] = wfm_ascii_dpo(fname, data_start, data_stop) 2 % Converts TSD5/6/7k and DPO7k/70k .wfm file to ASCII format 3 % with time array 4 % 5 % data_start and data_stop input arguments are optional 6 % and can be used to read parts of file 7 % 8 % To do: implement fast frame, pixel maps 9 % 10 out = []; 11 if nargin==0 12 fname=''; 13 end 14 if isempty(fname) 15 [filename,pname]=uigetfile({'*.wfm', 'Tektronix Waveform Files (*.wfm)';'*.*', 'All Files (*.*)'},'Choose Tektronix WFM file'); 16 fname=[pname filename]; 17 end 18 %---Open file 19 fd = fopen(fname,'r'); 20 if fd==-1 21 error('Problem opening file "%s"',fname) 22 end 23 %---Determine byte ordering, then close and reopen with proper byte ordering 24 ByteOrder = fread(fd,1,'ushort'); 25 if ByteOrder==61680 26 fclose(fd); 27 fd = fopen(fname,'r','ieee-be'); 28 else 29 fclose(fd); 30 fd = fopen(fname,'r','ieee-le'); 31 end 32 %---WFM static file information 33 out.ByteOrder = fread(fd, 1,'ushort' ); 34 out.VersionNum = fread(fd, 8,'*char' )'; 35 if ~any(strcmp(out.VersionNum,{':WFM#001';':WFM#002';':WFM#003'})) 36 fclose(fd); 37 error('File "%s" is not a valid WFM file',fname) 38 end 39 out.NumDigitsInByteCount = fread(fd, 1,'char' ); 40 out.NumBytesToEOF = fread(fd, 1,'long' ); 41 out.NumBytesPerPoint = fread(fd, 1,'char' ); 42 out.ByteOffsetToCurveBuffer = fread(fd, 1,'long' ); 43 out.HorZoomScale = fread(fd, 1,'long' ); 44 out.HorZoomPos = fread(fd, 1,'float32'); 45 out.VerZoomScale = fread(fd, 1,'double' ); 46 out.VerZoomPos = fread(fd, 1,'float32'); 47 out.WaveformLabel = fread(fd,32,'*char' )'; 48 out.N = fread(fd, 1,'ulong' ); 49 out.HeaderSize = fread(fd, 1,'ushort' ); 50 %---WFM header 51 out.SetType = fread(fd, 1,'int' ); 52 out.WfmCnt = fread(fd, 1,'ulong' ); 53 jnk = fread(fd,36,'uchar' ); % Skip these for now 54 out.DataType = fread(fd, 1,'int' ); 55 jnk = fread(fd,28,'uchar' ); % Skip these for now 56 switch out.VersionNum 57 case {':WFM#002' ':WFM#003'} 58 jnk = fread(fd, 1,'ushort'); % Skip these for now 59 end 60 jnk = fread(fd,12,'uchar' ); % Skip these for now 61 %---Explicit Dimension 1/2 62 s = []; 63 for n=1:2 64 s.DimScale = fread(fd, 1,'double'); 65 s.DimOffset = fread(fd, 1,'double'); 66 s.DimSize = fread(fd, 1,'ulong' ); 67 s.Units = fread(fd,20,'*char' ); 68 s.DimExtentMin = fread(fd, 1,'double'); 69 s.DimExtentMax = fread(fd, 1,'double'); 70 s.DimResolution = fread(fd, 1,'double'); 71 s.DimRefPoint = fread(fd, 1,'double'); 72 s.Format = fread(fd, 1,'int' ); 73 s.StorageType = fread(fd, 1,'int' ); 74 jnk = fread(fd,20,'uchar' ); % Skip these for now 75 s.UserScale = fread(fd, 1,'double'); 76 s.UserUnits = fread(fd,20,'*char' ); 77 s.UserOffset = fread(fd, 1,'double'); 78 switch out.VersionNum 79 case ':WFM#003' 80 s.PointDensity = fread(fd, 1,'double'); 81 otherwise 82 s.PointDensity = fread(fd, 1,'ulong' ); 83 end 84 s.HRef = fread(fd, 1,'double'); 85 s.TrigDelay = fread(fd, 1,'double'); 86 out.ExplicitDimension(n) = s; 87 end 88 %---Implicit Dimension 1/2 89 s=[]; 90 for n=1:2 91 s.DimScale = fread(fd, 1,'double'); 92 s.DimOffset = fread(fd, 1,'double'); 93 s.DimSize = fread(fd, 1,'ulong' ); 94 s.Units = fread(fd,20,'*char' )'; 95 jnk = fread(fd,16,'uchar' ); % Skip these for now 96 s.DimResolution = fread(fd, 1,'double'); 97 jnk = fread(fd,12,'uchar' ); % Skip these for now 98 s.UserScale = fread(fd, 1,'double'); 99 s.UserUnits = fread(fd,20,'*char' ); 100 s.UserOffset = fread(fd, 1,'double'); 101 switch out.VersionNum 102 case ':WFM#003' 103 s.PointDensity = fread(fd, 1,'double'); 104 otherwise 105 s.PointDensity = fread(fd, 1,'ulong' ); 106 end 107 s.HRef = fread(fd, 1,'double'); 108 s.TrigDelay = fread(fd, 1,'double'); 109 out.ImplicitDimension(n) = s; 110 end 111 %---Time Base 1/2 Information 112 s=[]; 113 for n=1:2 114 s.RealPointSpacing = fread(fd, 1,'ulong' ); 115 s.Sweep = fread(fd, 1,'int' ); 116 s.TypeOfBase = fread(fd, 1,'int' ); 117 out.TimeBase(n) = s; 118 end 119 %---WFM Update Spec 120 jnk = fread(fd,24,'uchar'); % Skip these for now 121 %---WFM Curve Information 122 jnk = fread(fd,10,'uchar'); % Skip these for now 123 PrechargeStartOffset = fread(fd, 1,'ulong'); 124 DataStartOffset = fread(fd, 1,'ulong'); 125 PostchargeStartOffset = fread(fd, 1,'ulong'); 126 PostchargeStopOffset = fread(fd, 1,'ulong'); 127 EndOfCurveBufferOffset = fread(fd, 1,'ulong'); 128 %---FastFrame Frames 129 %OPTIONAL 130 %---Curve Buffer 131 out.CurveSizeInBytes = PostchargeStartOffset - DataStartOffset; 132 out.CurveSize = out.CurveSizeInBytes / out.NumBytesPerPoint; 133 jnk = fread(fd,DataStartOffset,'uchar'); % Skip precharge 134 if nargin<3 135 data_start = 1; 136 data_stop = out.CurveSize; 137 end 138 switch out.NumBytesPerPoint 139 case 1 140 if data_start > 1 141 jnk = fread(fd,data_start-1,'*int8'); 142 out.CurveData = fread(fd,data_stop-data_start+1,'*int8'); 143 else 144 out.CurveData = fread(fd,data_stop,'*int8'); 145 end 146 case 2 147 if data_start > 1 148 out.CurveData = fread(fd,data_start-1,'*int16'); 149 out.CurveData = fread(fd,data_stop-data_start+1,'*int16'); 150 else 151 out.CurveData = fread(fd,data_stop,'*int16'); 152 end 153 end 154 155 %---Close file 156 fclose(fd); 157 %E_DimOffset = out.ExplicitDimension(1,1).DimOffset; 158 %E_DimScale = out.ExplicitDimension(1,1).DimScale; 159 %E_CurveData = out.CurveData; 160 %I_DimOffset = out.ImplicitDimension(1,1).DimOffset 161 %I_DimScale = out.ImplicitDimension(1,1).DimScale 162 y = (out.ExplicitDimension(1,1).DimOffset) + (out.ExplicitDimension(1,1).DimScale)*double(out.CurveData); 163 t = out.ImplicitDimension(1,1).DimOffset + out.ImplicitDimension(1,1).DimScale*(data_start:data_stop); 164 out_descript.Fs = 1/out.ImplicitDimension(1,1).DimScale; 165 out_descript.Ts = out.ImplicitDimension(1,1).DimScale; 166 out_descript.N = out.CurveSize; 167 out_descript.byte = out.NumBytesPerPoint; 168 outdata = y; 169 timedata = t;
调用函数：
1 clc 2 clear all 3 [out_descript,outdata,timedata]= wfm_ascii_dpo('Tek001.wfm') % wfm_ascii_dpo(fname,data_start,data_stop) 4 figure; 5 plot(timedata * 10^9,outdata * 200,'b-'); 6 xlabel('x') 7 ylabel('y)') 8 legend('map')