B=FIRRCOS(N,Fc,DF,Fs) returns an order N low pass linear phase FIR
filter with a raised cosine transition band. The filter has cutoff
frequency Fc, sampling frequency Fs and transition bandwidth DF (all in
Hz). The order of the filter, N, must be even.
Fc +/- DF/2 must be in the range [0,Fs/2].
The coefficients of B are normalized so that the nominal passband gain
is always equal to one.
FIRRCOS(N,Fc,DF) uses a default sampling frequency of Fs = 2.
B=FIRRCOS(N,Fc,R,Fs,'rolloff') interprets the third argument as the
rolloff factor instead of as a transition bandwidth. Alternatively, you
can specify B=FIRRCOS(N,Fc,DF,Fs,'bandwidth') which is equivalent to
B=FIRRCOS(N,Fc,DF,Fs).
R must be in the range [0,1].
B=FIRRCOS(N,Fc,DF,Fs,DESIGNTYPE) or
B=FIRRCOS(N,Fc,R,Fs,'rolloff',DESIGNTYPE)
will design a regular FIR raised cosine filter when DESIGNTYPE is
'normal' or set to an empty matrix. If DESIGNTYPE is 'sqrt', B is the
square root FIR raised cosine filter.
B=FIRRCOS(...,DESIGNTYPE,DELAY) allows for a variable integer delay to
be specified. When omitted or left empty, DELAY defaults to N/2.
DELAY must be an integer in the range [0, N+1].
B=FIRRCOS(...,DELAY,WINDOW) applies a length N+1 window to the designed
filter in order to reduce the ripple in the frequency response. WINDOW
must be a N+1 long column vector. If no window is specified a boxcar
(rectangular) window is used.
WARNING: Care must be exercised when using a window with a delay other
than the default.
[B,A]=FIRRCOS(...) will always return A = 1.
See also firls, fir1, fir2. Reference page in Help browser
doc firrcos ================================================================================= 你式中的“F0”其实是上面help中的“Fc”，也就是frequency频率，相应设置它的值即可。其中你都明白的香农定理为：0
