echomap::WindowFunctions::Blackman Struct Reference

The Blackman cosine-sum window. More...

#include <WindowFunctions.hpp>

Static Public Member Functions
static float	operator() (std::size_t index, std::size_t size) noexcept
	Maps the index into the Blackman function.

Detailed Description

The Blackman cosine-sum window.

Definition at line 180 of file WindowFunctions.hpp.

Member Function Documentation

operator()()

float echomap::WindowFunctions::Blackman::operator() ( std::size_t index, std::size_t size )

staticnoexcept

Maps the index into the Blackman function.

For a window of size \( M \), let \( N = M - 1 \).

\[ w[n] = 0.42 - 0.5\cos\left(\frac{2\pi n}{N}\right) + 0.08\cos\left(\frac{4\pi n}{N}\right) \]

for index \( n \).

This is the common approximate Blackman window, not the exact sidelobe-nulling Blackman variant.

Parameters

index	The index within the window.
size	The size of the window.

Returns

The Blackman-mapped index.

Definition at line 65 of file WindowFunctions.cpp.

{
    if (size <= 1)
        return 1.0f;
 
    const auto phase = 2.0f * std::numbers::pi_v<float> * static_cast<float>(index) / static_cast<float>(size - 1);
    return 0.42f - 0.5f * std::cos(phase) + 0.08f * std::cos(2.0f * phase);
}

---

The documentation for this struct was generated from the following files:

• src/objects/factories/WindowFunctions.hpp
• src/objects/factories/WindowFunctions.cpp