mula_pcm.m

现代通信系统（matlab版）（第二版）配套源代码 John G. Proakis等著 刘树棠 译 电子工业出版社出版

function [sqnr,a_quan,code]=mula_pcm(a,n,mu)
%MULA_PCM 	mu-law PCM encoding of a sequence
%       	[SQNR,A_QUAN,CODE]=MULA_PCM(A,N,MU).
%       	a=input sequence.
%       	n=number of quantization levels (even).
%       	sqnr=output SQNR (in dB).
%		a_quan=quantized output before encoding.
%		code=the encoded output.

[y,maximum]=mulaw(a,mu);
[sqnr,y_q,code]=u_pcm(y,n);
a_quan=invmulaw(y_q,mu);
a_quan=maximum*a_quan;
sqnr=20*log10(norm(a)/norm(a-a_quan));