📄 ecc.htm
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- saved from url=(0041)http://mmc.et.tudelft.nl/~richie/ecc.html -->
<HTML><HEAD>
<META content="text/html; charset=gb2312" http-equiv=Content-Type>
<SCRIPT language=JavaScript>
<!-- Script start
function Validate( aForm ) {
i = aForm.m.selectedIndex;
m = parseInt(aForm.m.options[i].text);
if(aForm.action.indexOf("rm-codec")==-1) {
t = parseInt(aForm.t.value);
n = (1<<m)-1;
} else {
r = parseInt(aForm.r.value);
n = (1<<m);
d = (1<<(m-r));
t = parseInt((d-1)/2);
if((r < 1) || (r > m)) {
alert( "r should be chosen between 1 and "+m );
return false;
}
}
k1 = n - m*t;
k2 = n - 2*t
if((m < 1) || (m > 15)) {
alert( "m should be chosen between 1 and 15" );
return false;
}
if((t < 0) || (t > n)) {
alert( "t should be chosen between 1 and 2^m-1 = " +n);
return false;
}
if(aForm.action.indexOf("rs-codec")!=-1) {
bst = parseInt(aForm.bstart.value);
blen = parseInt(aForm.blength.value);
if(aForm.etype[1].checked && (bst<0 || blen<1 ||
bst+blen>n*m)) {
alert( "Can't start a burst error of length "
+blen+" at position "+bst+
";\nwe only have "+n*m+" bits.");
return false;
}
}
return true;
}
function temp(x,y) {
temp.zero = x;
temp.one = y;
}
function calc(x,y) {
aForm = document.forms[x];
i = aForm.m.selectedIndex;
m = parseInt(aForm.m.options[i].text);
err = parseFloat(aForm.errorprob.value);
if(x==2) {
r = parseInt(aForm.r.value);
n = (1<<m);
d=(1<<(m-r));
if(d>2)
t=parseInt((d-1)/2);
else
t=0;
tt=t;
e = Math.round(err * n);
k = 1;
} else {
tt = parseInt(aForm.t.value);
t = tt;
n = (1<<m)-1;
e = Math.round(err * n);
k = n - m*t;
}
if(x==1) {
e = Math.round((1-Math.pow(1-err,m))*n)+" symbols";
k = n - 2*t;
bst = parseInt(aForm.bstart.value);
blen = parseInt(aForm.blength.value);
if(aForm.etype[1].checked) {
e = Math.max(0,Math.min(blen,n*m-bst))+" bits";
tt = m*(t-1)+1;
}
}
if(k<1) {
k=1;
tt = (1<<(m-1))-1;
}
if(x!=2) d = 2*tt + 1;
if(y == 'k') {
if(x==0) alert("k>="+k);
else alert("k=" +k);
}
else if (y == 'n') alert("n="+n);
else if (y == 'd') alert("d>="+d);
else if (y == 'e') alert("Expected number of errors: " + e +
"\nCorrecting capability: " + tt);
return true;
}
// script end -->
</SCRIPT>
<META content="MSHTML 5.00.2920.0" name=GENERATOR></HEAD>
<BODY>BCH codec:
<P>
<FORM action=cgi-bin/bch3-codec method=post name=bchcodec
onsubmit="return Validate(this);">m = <SELECT name=m> <OPTION
selected>3<OPTION>4<OPTION>5<OPTION>6<OPTION>7<OPTION>8<OPTION>9<OPTION>10<OPTION>11<OPTION>12<OPTION>13<OPTION>14<OPTION>15</OPTION></SELECT>
t = <INPUT maxLength=4 name=t size=4 value=1> <INPUT maxLength=1 name=n onclick="return calc(0,'n')" size=1 type=button value=" n = ? ">
<INPUT maxLength=1 name=k onclick="return calc(0,'k')" size=1 type=button value=" k >= ? ">
<INPUT maxLength=1 name=d onclick="return calc(0,'d')" size=1 type=button value=" d >= ? ">
<BR>Error probability per bit = <INPUT maxLength=4 name=errorprob size=5
value=0.10> <INPUT maxLength=1 name=e onclick="return calc(0,'e')" size=1 type=button value=" Expected number of errors ">
<BR><INPUT type=submit value=Code!> <INPUT type=reset value=重置> </FORM>
<P>
<HR SIZE=3 width="100%">
<P>Reed-Solomon codec:
<P>
<FORM action=cgi-bin/rs-codec method=post name=rs-form
onsubmit="return Validate(this);">m = <SELECT name=m> <OPTION
selected>3<OPTION>4<OPTION>5<OPTION>6<OPTION>7<OPTION>8<OPTION>9<OPTION>10<OPTION>11<OPTION>12<OPTION>13<OPTION>14<OPTION>15</OPTION></SELECT>
t = <INPUT maxLength=4 name=t size=4 value=1> <INPUT maxLength=1 name=n onclick="return calc(1,'n')" size=1 type=button value=" n = ? ">
<INPUT maxLength=1 name=k onclick="return calc(1,'k')" size=1 type=button value=" k = ? ">
<INPUT maxLength=1 name=d onclick="return calc(1,'d')" size=1 type=button value=" d >= ? ">
<BR><INPUT CHECKED name=etype type=radio value=stat> Error probability per bit =
<INPUT maxLength=4 name=errorprob size=5 value=0.10> <INPUT maxLength=1 name=e onclick="return calc(1,'e')" size=1 type=button value=" Expected number of errors ">
<BR><INPUT name=etype type=radio value=burst> Burst error with length <INPUT
maxLength=4 name=blength size=5 value=3> starting at data bit <INPUT maxLength=4
name=bstart size=5 value=0> <BR><INPUT type=submit value=Code!> <INPUT type=reset value=重置> </FORM>
<P>
<HR SIZE=3 width="100%">
<P>Reed-Muller codec:
<P>
<FORM action=cgi-bin/rm-codec method=post name=rmcodec
onsubmit="return Validate(this);">m = <SELECT name=m> <OPTION
selected>3<OPTION>4<OPTION>5<OPTION>6<OPTION>7<OPTION>8<OPTION>9<OPTION>10<OPTION>11<OPTION>12<OPTION>13<OPTION>14<OPTION>15</OPTION></SELECT>
r = <INPUT maxLength=4 name=r size=4 value=1> <INPUT maxLength=1 name=n onclick="return calc(2,'n')" size=1 type=button value=" n = ? ">
<INPUT maxLength=1 name=d onclick="return calc(2,'d')" size=1 type=button value=" d >= ? ">
<BR>Error probability per bit = <INPUT maxLength=4 name=errorprob size=5
value=0.10> <INPUT maxLength=1 name=e onclick="return calc(2,'e')" size=1 type=button value=" Expected number of errors ">
<BR><INPUT type=submit value=Code!> <INPUT type=reset value=重置>
</FORM></P></BODY></HTML>
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