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TCTAnalyse

TCTAnalyse User Guide


The class library has only a few classes, which deal with the TCT measurements taken. Although it is suited for the data format produced by Particulars PSTCT software, the class library can be tailored for any data format, by adding the load functions to the appropriate class.

The file format of the PSTCT.exe is composed of header including information about the measurements, followed by an array of taken waveforms (detailed description). There are 5 scanning parameters in PSTCT which results in 5 dimensional array. The length of the waveforms (WaveformLength) taken depends on the oscilloscope setting and number of channels taken (NCh). Therefore the produced files can be very large.
Size~ HeaderSize+Nx*Ny*Nz*NU1*NU2*NCh*Sizeof(float)*WaveformLength 
where Nx,Ny,Nz,NU1,NU2 denote number of steps for a given parameter (x,y,z, voltage source 1, voltage source 2). The format of the file is binary with every point stored as "float".

The PSTCT class is a standard interface to the data. An example of how individual waveforms can be accessed can be found in the folowing example . The constructor of the class takes the file name, time offset and byte order. These are the only paramerters. The time offset is requried to be inserted by hand so that t=0 marks the begining of the current pulse. This is important for the correction of the baseline (DC offset) of the waveforms. The DC level before t=0 is substracted from all the waveforms (CorrectBaseLine method). The third parameter in the constructor of the class is byte order of the float variable (endianess). On some platforms (unix) his may differ from the LabView (PC) and explicit byte order may be set (0=system default, 1=little, 2=big endian). Make sure that the same order is used as in DAQ.

Once the waveforms are loaded PrintInfo is usually used to see if the data are correctly read in. As already said the waveforms form a multidimensional array in the computer memory. For practical reasons the multidimensional array is organized as a 1D array with appropriate number of elements. For each set of parameters the appropriate waveform is found by calculation its position in this array (see method indx ). Each oscilloscope channel has its own array. The PSTCT class serves therefore for manipulation and presentation of this array. Any particular waveform can be reached by using method (function)
TH1F *stct.GetHA(ch,x,y,z,u1,u2);
which returns histogram with the waveform. Any subsequent analysis can therefore be based on this function (see ). Some operations/analysis of the waveforms are standard and are also included in the PSTCT class as methods.

Projections

One of the most used functions/methods is called Projection. It basically groupds several waveforms to a new class called MeasureWF. There are a lot of methods implemented in this class

Averaging