How to find amplitude frequency characteristics and phase frequency characteristics for discrete seq

Amplitude-frequency characteristics and phase-frequency characteristics generally describe the properties of a digital signal system, for example, we say the amplitude-frequency characteristics of a filter network. The amplitude-frequency characteristic and phase-frequency characteristic curves can be plotted according to the zero-pole distribution of the system function in the s-plane.

There should be a problem with the landlord's problem, what the discrete sequence can plot is the waveform of amplitude and phase. MATLAB.

abs(x) and (180 pi)*angle(x) and then plotted with a stem rod plot. I'll give you an example question:

Generate complex numerical signals:

x(n)=e (,10 n 10, plotting the waveform of its amplitude and phase.

Solution: n=[-10:10]; alpha=;

x=exp(alpha*n);

subplot(2,1,1);stem(n,abs(x));title('Amplitude');xlabel('n')

subplot(2,1,2);stem(n,(180/pi)*angle(x));title('Phase');xlabel('n')

With abs and angle:

clear,clc,close all;

w=:10;

f=am=abs(f);

ang=angle(f);

subplot(2,1,1);plot(w,am);title('Amplitude-frequency response');

subplot(2,1,2);plot(w,ang);title('Phase frequency response');

1. Shou Nian Ye first defines the Bernstein basis function, which is used to calculate the value of the corresponding Bernstein basis function in a given T point column.

2. Give the xy coordinates of the control vertices.

3. Define the point column of parameter t, define xx and yy as 0, and store the values of x coordinates and y coordinates corresponding to the calculated bezier curve respectively. Spine attack.

4. Calculate the value of the Bézier curve at the corresponding point column. According to the formula of the Bézier curve.

5. Draw the Bézier curve and the corresponding control polygons and vertices.

Refer to the following below:

2.Gives the xy coordinates of the vertices of the control, as shown in the following figure.

3.Define the point column of the parameter t, define xx and yy as 0, and find the plate values of the x coordinates and y coordinates corresponding to the stored and calculated Bézier curves, respectively.

4.Calculate the value of the Bézier curve in the corresponding point column. According to the Bezier curve formula.

5.Draw Bezier curves, control polygons and control vertices accordingly.

6.The plot of the function is shown in the figure below.

The logarithmic frequency bai rate characteristics of the system are obtained.

Figure (Bode Chart):

dubode()

Obtain the system Nai.

zhiQuest diagram dao (amplitude phase curve diagram or polar graph): The content format is as follows:

bode(num,den);

bode(num,den,w);

mag,phase,w]=bode(num,den,w);You try it.,See if it's okay.,If you have a problem, you'll communicate.。。

The top graph is the phase frequency characteristic curve, and the bottom one is the amplitude-frequency characteristic curve