i want to the fft for this bp but i have this error Error using fft Invalid data type. First argument must be double, single, int8, uint8, int16, uint16, int32, uint32, or log

Answer 1

[Star Strider]

Assuming that ‘bp’ does not contain any symbolic variables, perhaps this —

FTbp = fft(double(bp));

This also assigns it to a variable to make it easier to work with later.

.

[Star Strider]

My version of MATLAB cannot run incomplete images of code. It can only run actual complete code as text.

Copy and paste the actual text of your code to a Comment here. Then, I may be able to determine what the problem is and how to solve it.

[ahmad salahat]

syms x n t g b m z d k v p c s q bp ss
n=1:3

n = 1×3

1 2 3

w=(2*pi)/0.1

w = 62.8319

x=heaviside(t)-((t-0.05).*heaviside(t-0.05))+((t-0.1).*heaviside(t-0.1));
a0=(1/0.1)*int(x,t,0,0.1)

a0 = 

an=(2/0.1)*int(x*cos(n*w*t),t,0,0.1)

an = 

bn=(2/0.1)*int(x*sin(n*w*t),t,0,0.1)

bn = 

d=a0+an(1)*cos(w*t)+bn(1)*sin(w*t)

d = 

z=a0+an(2)*cos(2*w*t)+bn(2)*sin(2*w*t)

z = 

p=a0+an(3)*cos(3*w*t)+bn(3)*sin(3*w*t)

p = 

m=a0+an(1)*cos(w*t)+an(2)*cos(2*w*t)+an(3)*cos(3*w*t)+bn(1)*sin(w*t)+bn(2)*sin(2*w*t)+bn(3)*sin(3*w*t)

m = 

fplot(x,t)
hold on
fplot(t,m) 
hold off

k=(x-d)^2

k = 

v=(1/0.1)*int(k,t,0,0.1)

v = 

fs=400

fs = 400

t=0:(1/fs):1

t = 1×401

0 0.0025 0.0050 0.0075 0.0100 0.0125 0.0150 0.0175 0.0200 0.0225 0.0250 0.0275 0.0300 0.0325 0.0350 0.0375 0.0400 0.0425 0.0450 0.0475 0.0500 0.0525 0.0550 0.0575 0.0600 0.0625 0.0650 0.0675 0.0700 0.0725

c=10*cos(2*pi*200*t)

c = 1×401

10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10 10 -10

plot(t,c)

s=c*p

s = 

bpFilt = designfilt('bandpassfir','FilterOrder',1000, ...
    'CutoffFrequency1',200,'CutoffFrequency2',300, ...
    'SampleRate',1500);
fvtool(bpFilt)

This functionality is not available on remote platforms.

dataout=filter(bpFilt,s)

[Walter Roberson]

Your s contains symbolic values such as

sin(60*pi*t)/(6*pi) - cos(60*pi*t)/(9*pi^2) + 79/8

filter() is not able to process symbolic variables.

You cannot get fft() of symbolic variables. fft() is something that only applies to numeric data. To get a fourier transform of symbolic values you need to use fourier