Upsample the input signal by the factor osf.
osf
y = upsample(x,osf)
input signal
over-sampling factor
output, upsampled, signal
Insert osf-1 zeros between each input sample
y = upsample([1 2 3 4 5 6], 2); // y should be [1 0 2 0 3 0 4 0 5 0 6 0]