5.3.2 vsip_vcreate_kaiser_p - Create a Kaiser Window Vector

vsip_vview_f* vsip_vcreate_kaiser_f(vsip_length n, vsip_scalar_f beta, vsip_memory_hint hint);

Description

This function creates and initializes a vector with coefficients of a Kaiser window of length . The Kaiser window is defined by:

where is the zeroth-order modified Bessel function of the first kind.

Parameters

• vsip_length n: Length of the window (number of elements in the vector).

• vsip_scalar_p beta: Shape parameter that controls the trade-off between main lobe width and side lobe attenuation, .

• vsip_memory_hint hint: Memory allocation hint:

  • VSIP_MEM_NONE - No memory hint

  • VSIP_MEM_RDONLY - The memory is to be used read-only

  • VSIP_MEM_CONST - The memory will hold constants

  • VSIP_MEM_SHARED - The memory will be shared

  • VSIP_MEM_SHARED_RDONLY - The memory will be shared and is read-only

  • VSIP_MEM_SHARED_CONST - The memory will be shared and will hold constants

Return Value

• On success, returns a pointer to the newly created and initialized vector containing the Kaiser window coefficients.

• On error, returns NULL.

Example

vsip_vview_f *kaiser_win; 
vsip_length n = 64; 
vsip_scalar_f beta = 6.0f;  // Moderate side lobe suppression 
 
// Create a Kaiser window 
kaiser_win = vsip_vcreate_kaiser_f(n, beta, VSIP_MEM_NONE); 
 
if (kaiser_win == NULL) { 
    // Handle error 
} 
 
// Use the window in an application 
// For example, apply it to a signal 
vsip_vview_f *signal = vsip_vcreate_f(n, VSIP_MEM_NONE); 
vsip_vview_f *windowed_signal = vsip_vcreate_f(n, VSIP_MEM_NONE); 
 
// Initialize signal... 
// vsip_vramp_f(0.0f, 1.0f, signal); 
 
// Apply the window 
vsip_vmul_f(signal, kaiser_win, windowed_signal); 
 
// Clean up 
vsip_valldestroy_f(kaiser_win); 
vsip_valldestroy_f(signal); 
vsip_valldestroy_f(windowed_signal);

Notes

• The Kaiser window is symmetric for even-length vectors and nearly symmetric for odd-length vectors.

• Common values and their approximate side lobe attenuations:

  • : Rectangular window ( 13 dB)

  • :  30 dB side lobe attenuation

  • :  50 dB side lobe attenuation

  • :  60 dB side lobe attenuation