notchpeakargchk.m

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%> @file notchpeakargchk.m
%> @brief NOTCHPEAKARGCHK Validates the inputs for the IIRNOTCH and IIRPEAK
%> functions.
function [Ab, msg] = notchpeakargchk(Wo, BW, opts)
%   Author(s): P. Pacheco
%   Copyright 1999-2002 The MathWorks, Inc.
%   $Revision: 1.2 $  $Date: 2001/07/06 17:42:26 $
 
% Define default values.
Ab = abs(10*log10(.5)); % 3-dB width
msg = '';
 
% Check Wo and BW for notch/peak filters.
msg = freq_n_bandwidth(Wo, BW);
if msg
    return
end
 
% Parse and validate optional input args.
[Ab, msg] = parseoptions(Ab, opts);
if msg
    return
end
 
 
 
function msg = freq_n_bandwidth(Wo, BW)
% Check Wo and BW for notch/peak filters.
 
msg = '';
% Validate frequency cutoff and bandwidth.
if (Wo <= 0) || (Wo >= 1)
    msg = 'The frequency Wo must be within 0 and 1.';
    return;
end
 
if (BW <= 0) || (BW >= 1)
    msg = 'The bandwidth BW must be within 0 and 1.';
    return;
end
 
 
 
function [Ab, msg] = parseoptions(Ab, opts)
% Parse the optional input arguments.
 
msg = '';
if ~isempty(opts)
    [Ab, msg] = checkAtten(opts{1});
end
 
 
 
function [Ab, msg] = checkAtten(option)
% Determine if input argument is a scalar numeric value.
 
% Initialize output args.
Ab = [];
msg = '';
if isnumeric(option) && all(size(option)==1)  % Make sure it's a scalar
    Ab = abs(option);  % Allow - or + values
else
    msg = 'Level of decibels specified by Ab must be a numeric scalar.';
end
 
% [EOF]