Documentation

flattopwin

Flat top weighted window

所有的页面崩溃

Syntax

w = flattopwin(L)
w = flattopwin(L,sflag)

Description

平顶windows have very low passband ripple (< 0.01 dB) and are used primarily for calibration purposes. Their bandwidth is approximately 2.5 times wider than a Hann window.

w = flattopwin(L)returns theL-point symmetric flat top window in column vectorw.

w = flattopwin(L,sflag)returns theL-point symmetric flat top window usingsflagwindow sampling, wheresflagis either'symmetric'or'periodic'. The'periodic'flag is useful for DFT/FFT purposes, such as in spectral analysis. The DFT/FFT contains an implicit periodic extension and the periodic flag enables a signal windowed with a periodic window to have perfect periodic extension. When'periodic'is specified,flattopwincomputes a lengthL+1window and returns the firstLpoints. When using windows for filter design, the'symmetric'flag should be used.

Examples

collapse all

Open Live Script

Create a 64-point symmetric flat top window. View the result usingwvtool.

N = 64; w = flattopwin(N); wvtool(w)

Algorithms

平顶windows are summations of cosines. The coefficients of a flat top window are computed from the following equation:

w ( n ) = a 0 − a 1 cos ( 2 π n N − 1 ) + a 2 cos ( 4 π n N − 1 ) − a 3 cos ( 6 π n N − 1 ) + a 4 cos ( 8 π n N − 1 ) ,

where 0 ≤ n ≤ N − 1 . The coefficient values are

Coefficient Value
a0 0.21557895
a1 0.41663158
a2 0.277263158
a3 0.083578947
a4 0.006947368

References

[1] D’Antona, Gabriele, and A. Ferrero. Digital Signal Processing for Measurement Systems. New York: Springer Media, 2006, pp. 70–72.

[2] Gade, Svend, and Henrik Herlufsen. “Use of Weighting Functions in DFT/FFT Analysis (Part I).” Windows to FFT Analysis (Part I): Brüel & Kjær Technical Review, No. 3, 1987, pp. 1–28.

Extended Capabilities

See Also

Apps

Functions

Introduced before R2006a

Was this topic helpful?
Signal Processing Toolbox Documentation
万博1manbetx

Try MATLAB, Simulink, and Other Products

Get trial now