downsample

is there a matlab command that will filter and downsample data?

[Baba]

I found a command " decimate ". it seems like it does the trick. I have not tried it yet though.

[Walter Roberson]

decimate is in the signals processing toolbox

[Honglei Chen]

Be aware that decimate has limited filtering support, not as flexible as the ones I mentioned below.

[Baba]

yes, i noticed that only a chebishev I and FIR filters are available, as I understand for decimate command.

[Baba]

yep, the only toolbox that i have is the sptool

Answer 1

[Honglei Chen]

There are several possibilities. You can use either upfirdn or design the filter using fdesign.decimator and then filter your signal.

doc upfirdn
doc fdesign.decimator

Answer 2

[Walter Roberson]

imresize() in the Image Processing Toolbox

[Baba]

unfortunately i don't have that toolbox

[Walter Roberson]

There isn't any command for it in basic MATLAB. You may be able to construct routines for it out of basic MATLAB, depending on how you want to do your filtering. For example, you could fft2, adjust the frequency matrix, then ifft2() specifying fewer points than the original had.