function showcredit()

{

var credit

credit="Script programmed by Jens T.Saetre 03112000"

credit+="\n08122002 Changed layout"

credit+="\nUpdated 08122002"

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 main()

{

var InputPower,ReflectedPower,OutputPower



document.VSWRFORM.LOSS_PERCENT.value=formatvalue(Loss_Percent(), 5);

document.VSWRFORM.LOSS_DB.value= formatvalue( Loss_dB(), 5);

InputPower=1*document.VSWRFORM.InputPowerW.value;

OutputPower=10*log10(Output_Power());

ReflectedPower=InputPower- Output_Power();

document.VSWRFORM.ReflectedPower.value= formatvalue( 10*log10(ReflectedPower)+30, 5);

document.VSWRFORM.OutputPower.value= formatvalue(OutputPower+30, 5);

//document.VSWRFORM.InputPowerW.value=     formatvalue(   Math.pow(10,((InputPower)/10)), 5);

document.VSWRFORM.ReflectedPowerW.value= formatvalue(ReflectedPower, 5);

document.VSWRFORM.OutputPowerW.value=  formatvalue(Output_Power(), 5);









//window.prompt(Output_Power(),"Enter your name here.");



}





function OnChangeOutputPower()

{

var InputPower,OutputPower,ReflectedPower,vswr

InputPower=1*document.VSWRFORM.InputPowerW.value; 

OutputPower=1*document.VSWRFORM.OutputPowerW.value;

document.VSWRFORM.OutputPower.value= formatvalue(10*log10(OutputPower)+30, 5);

ReflectedPower=InputPower-OutputPower;

document.VSWRFORM.ReflectedPowerW.value= formatvalue(ReflectedPower, 5);

document.VSWRFORM.ReflectedPower.value= formatvalue((10*log10(ReflectedPower)+30), 5);





vswr= ( 1+ Math.sqrt(ReflectedPower/OutputPower) )/ ( 1 - Math.sqrt(ReflectedPower/OutputPower) );

document.VSWRFORM.VSWR.value=formatvalue(vswr, 5);



document.VSWRFORM.LOSS_PERCENT.value=formatvalue(Loss_Percent(), 5);

document.VSWRFORM.LOSS_DB.value= formatvalue( Loss_dB(), 5);





}



function OnChangeReflectedPower()

{

var InputPower,OutputPower,vswr

InputPower=1*document.VSWRFORM.InputPowerW.value; 

ReflectedPower=1*document.VSWRFORM.ReflectedPowerW.value;

OutputPower=InputPower-ReflectedPower;

document.VSWRFORM.OutputPowerW.value= formatvalue(OutputPower, 5);



document.VSWRFORM.OutputPower.value= formatvalue(((10*log10(OutputPower))+30), 5);





document.VSWRFORM.ReflectedPower.value=formatvalue((10*log10(ReflectedPower)+30), 5);

vswr= ( 1+ Math.sqrt(ReflectedPower/OutputPower) )/ ( 1 - Math.sqrt(ReflectedPower/OutputPower) );

document.VSWRFORM.VSWR.value=formatvalue(vswr, 5);

//window.prompt(vswr,"Enter your name here.");



document.VSWRFORM.LOSS_PERCENT.value=formatvalue(Loss_Percent(), 5);

document.VSWRFORM.LOSS_DB.value= formatvalue( Loss_dB(), 5);





}





function OnReflectedPowerdBm()

{

var ReflectedPowerdBm,ReflectedPower

ReflectedPowerdBm=1*document.VSWRFORM.ReflectedPower.value;



ReflectedPower=Math.pow(10,((ReflectedPowerdBm-30)/10) );

document.VSWRFORM.ReflectedPowerW.value=formatvalue( ReflectedPower, 5);



}





function OnOutputPowerdBm()

{

var OutputPowerdBm,OutputPower

OutputPowerdBm=1*document.VSWRFORM.OutputPower.value;



OutputPower=Math.pow(10,((OutputPowerdBm-30)/10) );

document.VSWRFORM.OutputPowerW.value=formatvalue( OutputPower, 5);



}









function OnChangeLossdB()

{

var vswr,loss_dB,loss_percent,factor



loss_dB=1*document.VSWRFORM.LOSS_DB.value;



loss_percent=100*(1- Math.pow(10, (-loss_dB/10)));



factor=Math.sqrt(loss_percent/100);



vswr= (factor+1)/(1-factor);



document.VSWRFORM.VSWR.value=formatvalue(vswr, 5);



}





function OnChangeLossPercent()

{

var vswr,loss_dB,loss_percent,factor

loss_percent=1*document.VSWRFORM.LOSS_PERCENT.value;

factor=Math.sqrt(loss_percent/100);

vswr= (factor+1)/(1-factor);

document.VSWRFORM.VSWR.value=formatvalue(vswr, 5);

}







function Loss_Percent()

{

var vswr,loss

vswr=1*document.VSWRFORM.VSWR.value;

loss=100* Math.pow(  (  (vswr-1)/(vswr+1)  ),2   );

return(loss);



}



function Output_Power()

{

var vswr,VSWRfactor,InputPower

vswr=1*document.VSWRFORM.VSWR.value;

VSWRfactor=Math.pow(  (  (vswr-1)/(vswr+1)  ),2   );

InputPower=1*document.VSWRFORM.InputPowerW.value;

return(InputPower/(1+VSWRfactor));

}





function Loss_dB()

{

return(-10*log10(1-(Loss_Percent()/100)));

}



function To_Watt(PowerdBm)

{

return(Math.pow( (PowerdBm/10),10)  );

}



function To_dBm(Power)

{

return(10*log10(Power)+30);

}



function To_Watt(Power)

{

return(Math.pow(10, (Power/10)));

}



function Convert_To_dBm()

{

var ReflectedPower,InputPower,OutputPower

InputPower=1*document.VSWRFORM.InputPowerW.value;

OutputPower=1*document.VSWRFORM.ReflectedPowerW.value;

ReflectedPower=1*document.VSWRFORM.ReflectedPowerW.value;

document.VSWRFORM.InputPower.value=formatvalue((10*log10(InputPower)+30), 5);

document.VSWRFORM.ReflectedPower.value= formatvalue((10*log10(ReflectedPower)+30), 5);

document.VSWRFORM.OutputPower.value= formatvalue((10*log10(OutputPower)+30), 5);



}





function Convert_To_Watt()

{

var InputPower,InputPowerW

InputPower=1*document.VSWRFORM.InputPower.value;

InputPowerW=To_Watt(InputPower-30);

document.VSWRFORM.InputPowerW.value=formatvalue((InputPowerW), 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);

}