function [yq] = quantize(y,B)
% 將信號量化為B位
% -------------------------
% [yq] = quantize(y,B)
%    yq = 量化后的信號(整數): 0 <= yq <= 2^B-1
%     y = 輸入信號
%     B = 位數/樣本
%
swing = (2^B-1)/2;
yq = round(y*swing+swing);