vsip_vcreate_cheby_p - Create a Chebyshev Window Vector

Core

This manual is preliminary and incomplete.
While our Core implementation implements all functions given in the standard we are still working on completing this documentation.

Please refer to the VSIPL standard for a complete function reference of the Core profile until we have completed work on this documentation.

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5.3.3 vsip_vcreate_cheby_p - Create a Chebyshev Window Vector

vsip_vview_f* vsip_vcreate_cheby_f(vsip_length n, vsip_scalar_f ripple, vsip_memory_hint hint);

Description

This function creates and initializes a vector with coefficients of a Chebyshev (Dolph-Chebyshev) window of length $n$ . The Chebyshev window is designed to have equal ripple in the passband and is optimal in the sense that it minimizes the main lobe width for a given side lobe level.

The ripple parameter specifies the side lobe level in decibels (dB), with typical values ranging from 40 to 120 dB. Higher ripple values result in better side lobe suppression but wider main lobes.

Parameters

vsip_length n: Length of the window (number of elements in the vector).
vsip_scalar_f ripple: Side lobe level in dB (typically 40-120 dB).
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 Chebyshev window coefficients.
On error, returns NULL.

Example

vsip_vview_f *cheby_win; 
vsip_length n = 64; 
vsip_scalar_f ripple = 60.0f;  // 60 dB side lobe attenuation 
 
// Create a Chebyshev window 
cheby_win = vsip_vcreate_cheby_f(n, ripple, VSIP_MEM_NONE); 
 
if (cheby_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, cheby_win, windowed_signal); 
 
// Clean up 
vsip_vdestroy_f(cheby_win); 
vsip_vdestroy_f(signal); 
vsip_vdestroy_f(windowed_signal);

Notes

The Chebyshev window provides the narrowest main lobe for a given side lobe level.
The window is symmetric for even-length vectors and nearly symmetric for odd-length vectors.
Common ripple values:
- 40 dB: Moderate side lobe suppression
- 60 dB: Good side lobe suppression
- 80 dB: Excellent side lobe suppression
- 100 dB: Very high side lobe suppression

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