diff options
Diffstat (limited to 'macros/rcosdesign.sci')
| -rw-r--r-- | macros/rcosdesign.sci | 86 |
1 files changed, 48 insertions, 38 deletions
diff --git a/macros/rcosdesign.sci b/macros/rcosdesign.sci index b3218c1..ba20ee2 100644 --- a/macros/rcosdesign.sci +++ b/macros/rcosdesign.sci @@ -1,19 +1,29 @@ function h = rcosdesign(rollof_factor, num_of_symb, samp_per_symb, varargin) // RCOSDESIGN computes the raised cosine FIR filter -// Inputs: +// Inputs: // rollof_fact: roll-off factor of the designed filter // num_of_symb: filter truncated to these many number of symbols // samp_per_symb: each symbol represented by these many samples // shape: returns a normal raised-cosine FIR filter when set to 'normal'. // returns a square-root raised cosing filter when set to 'sqrt'. -// Output: +// Output: // h: returned filter coefficients //The output result for the input parameter of shape 'normal' is not equivalent to the matlab output because of the use of sinc function in the computation. Matlab and scilab sinc functions seem to not be equivalent. +////EXAMPLE: +//rolloff = 0.25; +//span = 3; +//sample per symbol=sps=2; +//b=rcosdesign(rolloff,span,sps); +//OUTPUT: +//b=- 0.1210006 - 0.0456421 0.4418023 0.7590604 0.4418023 - 0.0456421 - 0.1210006 - // Check validity of number of inout arguments + + + +// Check validity of number of inout arguments checkNArgin(3, 4, argn(2)); - + // Check validity of input arguments valid_class_ROF = ['single', 'double']; properties_ROF = ['scalar', 'real', 'nonNegative']; @@ -21,7 +31,7 @@ function h = rcosdesign(rollof_factor, num_of_symb, samp_per_symb, varargin) if rollof_factor > 1 then error('roll-off factor should be <= 1'); end - + if rollof_factor == 0 then rollof_factor = number_peroperties("tiny"); end @@ -29,81 +39,81 @@ function h = rcosdesign(rollof_factor, num_of_symb, samp_per_symb, varargin) valid_class_NOS = ['single', 'double']; properties_NOS = ['scalar', 'real', 'positive', 'finite']; checkIpValidity(num_of_symb, valid_class_NOS, properties_NOS); - + valid_class_SPS = ['single', 'double']; properties_SPS = ['scalar', 'real', 'positive', 'finite', 'integer']; checkIpValidity(samp_per_symb, valid_class_SPS, properties_SPS); - + if pmodulo((num_of_symb*samp_per_symb), 2) ~= 0 then error('product of number_of_symbols and samples_per_symbol should be even'); end - - + + if argn(2) > 3 then shape = varargin(1); else shape = 'sqrt'; end - + valid_string_shape = ['sqrt', 'normal']; checkStringValidity(shape, valid_string_shape); - + // Designing the raised cosine filter - + pr = (samp_per_symb*num_of_symb)/2; ax = (-pr:pr)/samp_per_symb; - + if ~strcmpi(shape, 'normal') then den = (1-(2*rollof_factor*ax).^2); id1 = find(abs(den) > sqrt(%eps)); for idx = 1:length(id1) filt_resp(id1(idx)) = sinc(ax(id1(idx))).*(cos(%pi*rollof_factor*ax(id1(idx)))./den(id1(idx)))/samp_per_symb; end - + id2 = 1:length(ax); id2(id1) = []; for idx = 1:length(id2) filt_resp(id2(idx)) = rollof_factor*sin(%pi/(2*rollof_factor))/(samp_per_symb); end - - + + else id1 = find(ax == 0); if ~isempty(id1) then filt_resp(id1) = (-1)./(%pi.*samp_per_symb).*(%pi.*(rollof_factor-1) - 4.*rollof_factor); end - + id2 = find(abs(abs(4.*rollof_factor.*ax) - 1.0) < sqrt(%eps)); if ~isempty(id2) then filt_resp(id2) = 1 ./ (2.*%pi.*samp_per_symb) * (%pi.*(rollof_factor+1) .* sin(%pi.*(rollof_factor+1)./(4.*rollof_factor)) - 4.*rollof_factor .* sin(%pi.*(rollof_factor-1)./(4.*rollof_factor)) + %pi.*(rollof_factor-1) .* cos(%pi.*(rollof_factor-1)./(4.*rollof_factor)) ); end - + id = 1:length(ax); id([id1 id2]) = []; nid = ax(id); a = (-4.*rollof_factor./samp_per_symb); b = ( cos((1+rollof_factor).*%pi.*nid) + sin((1-rollof_factor).*%pi.*nid) ./ (4.*rollof_factor.*nid) ); c = (%pi .* ((4.*rollof_factor.*nid).^2 - 1)); - + for idx = 1:length(id) filt_resp(id(idx)) = a*b(idx)/c(idx); idx end - - + + end - + filt_resp = filt_resp / sqrt(sum(filt_resp.^2)); - + h = filt_resp'; - + endfunction function checkNArgin(min_argin, max_argin, num_of_argin) if num_of_argin < min_argin then error('Not enough input arguments') end - + if num_of_argin > max_argin then error('Too many input arguments') end @@ -112,7 +122,7 @@ endfunction function checkIpValidity(variable, valid_class, properties) // Function to check the validity of the input variable -// Inputs: +// Inputs: // valid_class: vector of valid classes for the input variable // properties: vector of necessary properties of the input variable @@ -122,9 +132,9 @@ function checkIpValidity(variable, valid_class, properties) error('input variable should be of type double '); end end - + end - + for jdx = 1:length(length(properties)) if ~strcmpi(properties(jdx), 'scalar') then if length(variable) > 1 then @@ -137,43 +147,43 @@ function checkIpValidity(variable, valid_class, properties) error('Input variable is empty. It is invalid'); end end - + if ~strcmpi(properties(jdx), 'nonNan') then if isnan(variable) then error('Input variable is not a number (Nan). It is invalid'); end end - + if ~strcmpi(properties(jdx), 'real') then if ~isreal(variable) then error('Input should be real'); end end - + if ~strcmpi(properties(jdx), 'positive') then if variable <= 0 then error('Input should be positive'); end end - + if ~strcmpi(properties(jdx), 'integer') then if (int(variable)-variable) ~= 0 then error('Input should be an integer'); end end - + if ~strcmpi(properties(jdx), 'nonNegative') then if variable < 0 then error('Input should be non-negative'); end end - + if ~strcmpi(properties(jdx), 'finite') then if ~(abs(variable) < %inf) then error('Input should be finite'); end end - + end endfunction @@ -181,9 +191,9 @@ endfunction function checkStringValidity(variable, valid_strings) if ~strcmpi(valid_strings(1), variable) | ~strcmpi(valid_strings(2), variable) then - + else error('Input string is not recognized') - end - + end + endfunction |