Matlab code to Upsample a given sequence.

[Prosenjit101]

Here i have a code to downsample a given sequence.

in editor:

function[y]= dns(x)
k = input('Enter downsampling factor = ')
y= x(1:k:length(x));
end

in command window:

>> x = [ 1 2 3 4 5 6 7 8 9 10 11 12]
>> dns(x)
Enter downsampling factor = 3

k =

3


ans =

1 4 7 10


I need a similar type of code for upsampling.

 

[keremcant]

Hi,
the upsampling is not that straight forward as down sampling.
there are various methods to do the upsampling, the easiest in my opinion is linear interpolation, but you can use quadratic methods, cubic spline interpolation etc... depends on why you need it for...
so you have to specify your application a bit more.
would recommend you to read at least the wiki page of interpolation: https://en.wikipedia.org/wiki/Interpolation

 

[Pulkit Varshney]

for linear interpolation...

close all;
clear all;
x = [ 1 2 3 4 5 6 7 8 9 10 11 12]
k = input('Enter downsampling factor = ');
z=[];
for i=1:length(x)-1
m=(x(i+1)-x(i))/k;
for j=1:k-1
y(1,j)=x(i)+j*m;
end
z=[z x(i) y];
end
z=[z x(length(x))]


Enter downsampling factor = 2

z =

Columns 1 through 9

1.0000 1.5000 2.0000 2.5000 3.0000 3.5000 4.0000 4.5000 5.0000

Columns 10 through 18

5.5000 6.0000 6.5000 7.0000 7.5000 8.0000 8.5000 9.0000 9.5000

Columns 19 through 23

10.0000 10.5000 11.0000 11.5000 12.0000