Hi,If you need a discrete linear filter, all you need to do is implement the equation a(1)*y(n) = b(1)*x(n) + b(2)*x(n-1) + ... + b(nb+1)*x(n-nb) - a(2)*y(n-1) - ... - a(na+1)*y(n-na) where a(1:na+1) and b(1:nb+1) are the coefficients of the denominator and numerator respectively. If you need only an FIR filter you can use 'conv' function for convolution which does not need any toolboxes. For simple echo effect the audio signal is added to its own delayed version which does not need filter. Navan --- wrote: > I am a new user for matlab. I need to know how to > implement a filter of any > kind without using the tool box . I mean only using > programming . If anyone > has any example of a code of a digital filter of any > kind ( making an echo > effect for ex ) and applying it on a wav file ,plz > send it to me or if u > know any good links i will appreciate this so much. > Thanks in advance, __________________________________________________ |