Fir filter designing in matlab

[saad zulfiqar]

I am studying digital signal processing subject and our Professor gives us a task of modulation and demodulation and then design appropriate Fir low pass filter in matlab. I have done modulation and demodulation but i am stuck in filter designing. I want to know how the filter's order is determine from its transition width ?
Can anyone help me!

 

[2010ee179]

Type fdatool in MATLAB. It'll open some GUI. Here you can specify :

>>your response type as lowpass
>>design method FIR (there will be a drop down menu...choose equiripple if you are not sure what to do with this)
>>select minimum order
>>choose Fs, Fpass and Fstop (Fstop - Fpass is your transition width)
>>choose passband and stop band attenuation
>>then press design filter and it will give minimum order required for your specs