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|Home MathPack Math2 Procedures and Functions CalcSincHPKernel|
|See also: CalcSincBSKernel, CalcSincBPKernel, CalcSincLPKernel, MovingKernelFilter|
The procedure CalcSincHPKernel calculates the coefficients of a highpass sinc filter. The coefficients which are returned in the array FilterKernel can be used by the function MovingKernelFilter to apply a highpass filter to a signal. The open array  or vector  FilterKernel is automatically resized to contain KLeng elements.
The parameter KLeng determines the roll-off of the filter. As a rule of thumb the transition bandwidth BW can be estimated by
BW = 4/KLeng.The parameter CutOffFQ controls the cutoff frequency, which is specified as a fraction of the sampling rate. Thus the CutOffFQ parameter may assume values between 0 and 0.500. The following figure shows the influence of the kernel length on the roll-off at a fixed cutoff frequency (left diagram, fc = 0.2) and the roll-off of different cutoff frequencies using the same kernel length (right diagram, KLeng = 41).
The parameter Windowing determines the type of windowing applied to the filter kernel. Currently the following windowing modes are supported:
0 ... no windowing