How to generate correlated noise

Hi to everyone. I have to generate some correlated noise with Gaussian-like pdf and autocorrelation. It's quite simple in theory: incorrelated Gaussian noise generated with randn(1,...) filtered with a 1D Gaussian FIR filter, whose impulse response is equal to the desired noise autocorrelation. My issue is to implement the Gaussian FIR filter. I could use gaussdesign(bt,span,sps): - bt: the 3dB passband - span: number of symbols - sps: samples per symbol But I don't know how to use 'span' and 'sps'.