command 'downsample' in matlab doesn't work

for example :

x = [1 2 3 4 5 6 7 8 9 10];
y = downsample(x)

we see :

y =

       2     4     6     8    10

but for :

x = [1 2 3 4 5 6 7 8 9 10];
y = downsample(x,3)

it doesn't work

in matlab R2011b

Answer 1

[Wayne King]

I think you need to give the error message, if any, you receive in R2010b. Do you have the Signal Processing Toolbox in your R2010b installation?

Enter

>>ver

to make sure you have the SP Toolbox.

I have no problem with this:

x = [1 2 3 4 5 6 7 8 9 10]; 
y = downsample(x,3);

in R2010b.

[amid aliaghazadeh]

yes I have

[Wayne King]

Then what is not working for you. What error message are you getting?

[amid aliaghazadeh]

??? Error using ==> downsample

Too many input arguments.

Answer 2

[Wayne King]

Please enter:

>>which downsample

at the command line. I think in your R2010b version you have some other downsample.m (which is not the MATHWORKS version).

If this other downsample.m precedes the MATHWORKS version on your path, then you are calling that program and not the MATHWORKS version.

If you do not get back something like:

toolbox/signal/signal/downsample.m

then you have a different version of downsample.m

[amid aliaghazadeh]

thank you for your help