DC component remover

Syntax

Hd = dcremover (Fc, DFormat)

Description

Implements a first order IIR highpass filter (DC component remover), defined in general as:

$$\displaystyle H(z)=G\times\Big(\frac{1-z^{-1}}{1-\alpha z^{-1}}\Big)$$

Defining this alpha filter in terms of a cut-off frequency, $$w_c$$,

$$\displaystyle H(z)=\frac{1}{w_c+1} \bigg( \frac{1-z^{-1}} {1+\frac{w_c-1}{w_c+1} z^{-1}} \bigg) = \frac{1-z^{-1}}{(w_c+1)+(w_c-1)z^{-1}}$$

Fc: -3dB cut-off frequency, given by: $$w_c = \tan (\frac{\pi F _c}{f s})$$

DFormat: allows you to specify the display format of resulting digital filter object.

 symbolic Display a symbolic representation of the filter object. numeric Display a matrix representation of the filter object void Create a filter object, but do not display output

Example

ClearH1;  // clear primary filter from cascade
ShowH2DM;   // show DM on chart

Main()

F=5;
Hd=dcremover(Fc,"symbolic");

Num = getnum(Hd); // define numerator coefficients
Den = getden(Hd); // define denominator coefficients
Gain = getgain(Hd); // define gain