lagrange

来自 fdesign.fracdelay 设定对象的小数延迟滤波器

语法

Hd = design(d,'lagrange')
hd = design(d,'lagrange',FilterStructure,structure)

说明

Hd = design(d,'lagrange') 根据 d 中的设定，使用拉格朗日方法设计小数延迟滤波器。

hd = design(d,'lagrange',FilterStructure,structure) 指定拉格朗日设计方法和 hd 的 structure 滤波器结构。唯一有效的滤波器结构是 fd，它描述小数延迟结构。

示例

此示例使用 0.30 个采样的小数延迟。help 和 designopts 命令提供有关设计小数延迟滤波器的详细信息。

d=fdesign.fracdelay(.30)
 
d =
 
               Response: 'Fractional Delay'
          Specification: 'N'               
            Description: {'Filter Order'}  
              FracDelay: 0.3               
    NormalizedFrequency: true              
            FilterOrder: 3                 
                                           
designmethods(d)

Design Methods for class fdesign.fracdelay (N):

lagrange

help(d,'lagrange')

DESIGN Design a Lagrange fractional delay filter.
HD = DESIGN(D, 'lagrange') designs a Lagrange filter specified by the
  FDESIGN object D, and returns the DFILT object HD.
 
HD = DESIGN(..., 'FilterStructure', STRUCTURE) returns a filter with the
 structure STRUCTURE.  STRUCTURE is 'farrowfd' by default and can be any of
 the following:

'farrowfd'
'fd'
 
 % Example #1 - Design a linear Lagrange fractional delay filter of 0.2 samples.
 h = fdesign.fracdelay(0.2,'N',2);
 Hd = design(h, 'lagrange', 'FilterStructure', 'farrowfd')
 
 % Example #2 - Design a cubic Lagrange fractional delay filter
 Fs = 8000;      % Sampling frequency of 8kHz
 fdelay = 50e-6; % Fractional delay of 50 microseconds.
 h  = fdesign.fracdelay(fdelay,'N',3,Fs);
 Hd = design(h, 'lagrange', 'FilterStructure', 'farrowfd');

此示例设计一个线性拉格朗日小数延迟滤波器，其中延迟设置为 0.2 秒，滤波器阶数 N 设置为 2。

h = fdesign.fracdelay(0.2,'N',2); 
hd = design(h,'lagrange','FilterStructure','farrowfd')

设计一个滤波器阶数等于 3 的三次拉格朗日小数延迟滤波器。

Fs = 8000;      % Sampling frequency of 8 kHz.
fdelay = 50e-6; % Fractional delay of 50 microseconds.
h  = fdesign.fracdelay(fdelay,'N',3,Fs);
hd = design(h,'lagrange','FilterStructure','farrowfd');

参考资料

Laakso, T. I., V. Välimäki, M. Karjalainen, and Unto K. Laine, “Splitting the Unit Delay - Tools for Fractional Delay Filter Design,” IEEE® Signal Processing Magazine, Vol. 13, No. 1, pp. 30-60, January 1996.

版本历史记录

在 R2011a 中推出

另请参阅

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