Cosine bell function

The size of the window must be carefully fit to the FID being processed. Varian uses the parameter sb to describe the width (in seconds) of the sine-bell window from the 0° point to the 90° point. Thus for an unshifted sine-bell function, we want the 0° to 180° portion of the sine function (2 sb) to just fit over the time duration of the FID at). This is accomplished by setting the value of sb to one-half the acquisition time sb = at/2. Since the sine-bell is not shifted, the sine-bell shift (sbs) is set to zero. For a cosine-bell or 90° shifted sine-bell window, we want the portion of the sine function from 90° to 180° (or sb, since the 0° to 90° portion is of the same duration as the 90° to 180° portion) to just fit over the FID (duration at) sb = at. In addition, the whole sine function is shifted to the left side by the duration of the FID, so we set the parameter sbs (sine-bell shift) equal to —at (left shift corresponds to a negative number). In F we do not have a parameter for acquisition time at) in t, but we know that the maximum t value is just the number of data points times the sampling delay ... 

So you can just set sbl = nilswl and sbsl = —sbl for a 90°-shifted sine-bell, and sbl = nil(2 x swl) and sbsl = 0 for an unshifted sine-bell. Bruker uses the parameter wdw (in both F and To) to set the window function (SINE = sine-bell, QSINE = sine-squared, etc.) and ssb for the sine-bell shift. For example, if ssb = 2, the sine function is shifted 90° (180°/ssb) and we get a simple cosine-bell window. For an unshifted sine-bell, use ssb = 0. 

Shifted sine bell function. An apodization function with the amplitude of the sinusoidal pattern starting at a maximum and dropping to zero. The first quarter of a cosine waveform. 

In our estimation of the baseline and ptunp cycle, we must exclude the sulfate peak. To specify the computations, we define a weight fimction w(t). This weight function includes the cosine-bell tapering of the ends of the Intervals needed to reduce the bias in spectral estimation (2). Let the Interval to be excluded because it has the sulfate peak be denoted by [tj, t, ]. We let... 

Figure 3 shows the intensities of the electric field as a function of incidence angle where media 1 and 2 are silica (ni=1.46) and water (n2=l-33), respectively. The intensities of both p- and s-polarizations increase with incidence angle for d

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