function [Rp,As] = delta2db(delta1,delta2)
%  從絕對delta 標度變換為相對dB標度. 
% ---------------------------------------------------------
% [Rp,As] = delta2db(delta1,delta2)
% [d1,d2] = db2delta(Rp,As)
% Rp = 通帶波動
% As = 阻帶衰減
% d1 = 通帶容差
% d2 = 阻帶容差
%
Rp = -20*log10((1-delta1)/(1+delta1));
As = -20*log10(delta2/(1+delta1));