<!--
{
  "documentType" : "article",
  "framework" : "Accelerate",
  "identifier" : "/documentation/Accelerate/finite-impulse-response-filters",
  "metadataVersion" : "0.1.0",
  "role" : "collectionGroup",
  "title" : "Finite impulse response filters"
}
-->

# Finite impulse response filters

Perform finite impulse response filtering with decimation and antialiasing on vectors of real or complex values.

## Topics

### FIR Filter Creation

[`extern void vDSP_wiener(vDSP_Length __L, const float *__A, const float *__C, float *__F, float *__P, int __Flag, int *__Error);`](/documentation/Accelerate/vDSP_wiener)

Solves a system of linear equations for a single-precision symmetric Toeplitz coefficient matrix.

[`extern void vDSP_wienerD(vDSP_Length __L, const double *__A, const double *__C, double *__F, double *__P, int __Flag, int *__Error);`](/documentation/Accelerate/vDSP_wienerD)

Solves a system of linear equations for a double-precision symmetric Toeplitz coefficient matrix.

### Real Vectors

  <doc://com.apple.accelerate/documentation/Accelerate/resampling-a-signal-with-decimation>

[`static func downsample<T, U>(U, decimationFactor: Int, filter: T) -> [Double]`](/documentation/Accelerate/vDSP/downsample(_:decimationFactor:filter:)-1o8it)

Returns the downsampled double-precision vector.

[`static func downsample<T, U>(U, decimationFactor: Int, filter: T) -> [Float]`](/documentation/Accelerate/vDSP/downsample(_:decimationFactor:filter:)-40d8o)

Returns the downsampled single-precision vector.

[`static func downsample<T, U, V>(U, decimationFactor: Int, filter: T, result: inout V)`](/documentation/Accelerate/vDSP/downsample(_:decimationFactor:filter:result:)-2y1iv)

Calculates the downsampled double-precision vector.

[`static func downsample<T, U, V>(U, decimationFactor: Int, filter: T, result: inout V)`](/documentation/Accelerate/vDSP/downsample(_:decimationFactor:filter:result:)-1g4a)

Calculates the downsampled single-precision vector.

[`extern void vDSP_desamp(const float *__A, vDSP_Stride __DF, const float *__F, float *__C, vDSP_Length __N, vDSP_Length __P);`](/documentation/Accelerate/vDSP_desamp)

Performs single-precision FIR filtering with decimation and antialiasing.

[`extern void vDSP_desampD(const double *__A, vDSP_Stride __DF, const double *__F, double *__C, vDSP_Length __N, vDSP_Length __P);`](/documentation/Accelerate/vDSP_desampD)

Performs double-precision FIR filtering with decimation and antialiasing.

### Complex Vectors

[`extern void vDSP_zrdesamp(const DSPSplitComplex *__A, vDSP_Stride __DF, const float *__F, const DSPSplitComplex *__C, vDSP_Length __N, vDSP_Length __P);`](/documentation/Accelerate/vDSP_zrdesamp)

Performs complex-real single-precision FIR filtering with decimation and antialiasing.

[`extern void vDSP_zrdesampD(const DSPDoubleSplitComplex *__A, vDSP_Stride __DF, const double *__F, const DSPDoubleSplitComplex *__C, vDSP_Length __N, vDSP_Length __P);`](/documentation/Accelerate/vDSP_zrdesampD)

Performs complex-real double-precision FIR filtering with decimation and antialiasing.


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)