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    function newval = todb(h,val,passOrStop)
%TODB Convert linear value to dB.

%   Author(s): R. Losada
%   Copyright 1988-2002 The MathWorks, Inc.

switch passOrStop,
    
case 'pass',
    newval = 20*log10((1+val)/(1-val));
    
case 'stop',
    newval = -20*log10(val);
end