function showcredit()

{

var credit

credit="Orginal script programmed by Jens T.Saetre 07012001"

credit+="\n08122002 Changed layout"

credit+="\n15022004 Agilent E4402B calculations added by Michael Gamst"

window.alert(credit);







//var theResponse = window.prompt("Welcome?","Enter your name here.");

}



function log10(X)

{

return( Math.log(X)/Math.log(10)  );

// works OK !

}



function exp10(x) {

   var y;

   y = Math.exp(x*Math.log(10));   // a^x = b^(x * log_b(a))

   return(y);

}





function calculate_power()

{



var noisedensity,symbolrate,imp

var sa_correctionfactor=2.51;



noisedensity=1*document.Power.NoiseDensity.value;

symbolrate=1*document.Power.Symbolrate.value;

imp=1*document.Power.imp.value;



power= noisedensity + 10*log10(symbolrate*1000) -sa_correctionfactor;



document.Power.Power.value=formatvalue(power, 5)





   

   p = exp10(power/10)/1000;

   u = Math.sqrt(p*imp);

   dBuV = 20*log10(u*1000000);   

voltage= dBuV;   

document.Power.Voltage.value=formatvalue(voltage, 5)}







function formatvalue(input, rsize) // Desimal avrunding

  {

   var invalid = "**************************";

   var nines = "999999999999999999999999";

   var strin = "" + input;

   var fltin = parseFloat(strin);

   if (strin.length <= rsize) return strin;

   if (strin.indexOf("e") != -1 ||

       fltin > parseFloat(nines.substring(0,rsize)+".4"))

      return invalid.substring(0, rsize);

   var rounded = "" + (fltin + (fltin - parseFloat(strin.substring(0, rsize))));

   return rounded.substring(0, rsize);

}