<!--
 w1 = "dB";
 w2 = "Ra";
 ww =  w1 + "_" + w2;
 opt1 = "dB";
 opt2 = "";
 
 b = 0;
 x = 0;
 y = 0;
 z = 0;
 r = 0;
 br = "P";
 fsi = 120*Math.PI;

function Resultat(ve,vf)
{	if (ve!='') {w2 = ve; opt2 = vf;}
	x = window.document.dBcalc.DispX.value;
	x = eval(x); DispX();
	if (w2 == 'R') {y1=''; DispY1(y1);} 
else 
	{
	r = window.document.dBcalc.DispR.value;
	ww = w1 + "_" + w2;
	if (window.document.dBcalc.Bouton[0].checked) {br = 'U';} else {br = 'P';}
	z=''; vy1= opt2; vz1='';	 
	Calcul();
	Disp();
	}
}

function Disp()
{	 	
	if (y == 'not available') 
		{DispY(y); DispY1(opt2);}
else  
{	pf='';
	if (w2 =='V' || w2 == 'A' || w2 == 'W' || w2 == 'T' || w2 == 'TT' || w2 == 'mp' || w2 == 'Vm' || w2 == 'Wm') 
		{Prefix(y); y= va; if (pf !=' ') {vy1= pf+vy1;} }
	Round(y); y= va;
	if (w2 == 'T' || w2 == 'TT' || w2 == 'mp') 
		{Prefix(z); z= va; Round(z); z= va; if (pf !=' ') {vz1= pf+vz1;}} 
	
	DispY(); DispY1(vy1); DispZ(); DispZ1(vz1);
}
}

function Round(vx)
{	if (vx > 0.1 || vx < - 0.1)              
{va = (Math.round(vx*10000))/10000;}
else
{va =vx;} 
 return va;         
}

function Prefix(vla)
{ 	
	va = vla; pf = '';
	var ex = 0;
	if (va>1000)
		{
			while ((va/1000 > 1)&&(ex <= 7))
	   			{va=va/1000;ex++;}  
		} 
	else
	{ 
	while ((va*1000 < 1000)&&(ex <= 7))
		{	va=va*1000; ex++;}
	ex = ex + 9
	}
	
	Pfx = " kMGTPEZY mµnpfazy";
	pf = Pfx.substr(ex,1)
	return va, pf; 
	
}


function DispX()
{ 	window.document.dBcalc.DispX.value=x;}


function DispY()
{ 	window.document.dBcalc.DispY.value=y;}


function DispY1(y1)
{ 	window.document.dBcalc.DispY1.value=y1;}

function DispZ()
{ 	window.document.dBcalc.DispZ.value=z;}

function DispZ1(z1)
{ 	window.document.dBcalc.DispZ1.value=z1;}

function Rref()
 {	r = window.document.dBcalc.DispX.value; if (r == 0) {r =50;}
 {	window.document.dBcalc.DispR.value=r}
 }

function ClearR()
{	window.document.dBcalc.reset();
	Check();
}


function ClearS()
{	x=''; DispX(); y=''; DispY(); DispY1(y); z=''; DispZ(); z1=''; DispZ1(z1);
	Check(); 
}


function Conv_1(it)
  {	w1   =  it.options[it.selectedIndex].value; 
	opt1 =  it.options[it.selectedIndex].text; 

  }

function Add(n)
 {window.document.dBcalc.DispX.value = window.document.dBcalc.DispX.value + n;}

function Check()
{	   it =  window.document.dBcalc.choixCa;
	w1 = it.options[it.selectedIndex].value; opt1= it.options[it.selectedIndex].text;

}
   
function Bel(ra)
 {bel = Math.log(ra)/Math.log(10);    //   ln/ln(10) = log(base 10) 

	 bel = Math.round (100000*bel+0.00005)/100000;
	
 return bel;}

function Pathloss()
{	d = window.document.dBcalc.DispY.value;
	f  = window.document.dBcalc.DispZ.value;
	if (d > 0.3/f /2*Math.PI)
		{x= Math.round(2000*Bel(4*Math.PI*d*f/.3))/100;}
	else 
		{x = 'd > lambda/2*TT';}
	if (f == '')
		{x = '';}
	vy1= 'd (km)'; vz1= 'f (MHz)';
	DispX();  DispY1(vy1); DispZ1(vz1); 
        window.document.dBcalc.choixCa.value = 'dB'
}


function V_A(){y = x/r;}
function V_W(){y = x*x/r; }
function V_dBV(){y = 20*Bel(x)}
function V_dBmV(){y = 20*Bel(x)+60}
function V_dBuV(){y = 20*Bel(x/1E-6)}
function V_dBuA(){y = 20*Bel(x/r/1E-6);}
function V_dBm(){y = 10*Bel((x*x/r)*1000); y = Math.round (10000*y+0.0005)/10000;}

function A_V(){y = x*r;a=1;}
function W_V(){y = Math.sqrt(x*r);a=1;}
function dBm_V(){y=x/10; y= Math.pow(10,y); y= y/1000; y =Math.sqrt(y*r);a=1;}
function dBuV_V(){ y=x/20; x=Math.pow(10,y); y=x*1E-6;a=1;}
function dBmV_V(){ y=x/20; x=Math.pow(10,y); y=x*1E-3;a=1;}

function dBV_V(){y=x/20; y= Math.pow(10,y);a=1;}
function dBuA_V() {y=x/20; y=Math.pow(10,y)*r*1E-6;a=1;}

function Vm_Wm(){y = x*x/fsi; }
function Wm_Vm(){y = Math.sqrt(x*fsi);a=1;}


function dB_Ra()
 {
 if (br == 'U')
	{y=x/20; y= Math.pow(10,y);}
 else
	{y=x/10; y= Math.pow(10,y);}
 }

function vs_dB()
{	
	y= (x-1)/(x+1);
	y = - 20*Bel(y);
}

function x_vs()
{	
        y = Math.sqrt(y); 
        y= (1+y)/(1-y);
        vy1= "VSWR"; return vy1;
}

function x_vsb()
{	
 if (br == 'P') {y = Math.sqrt(y);} 
        y= (1+y)/(1-y);
        vy1= "VSWR"; return vy1;
}

function Ra_dB()
 { if (br=='U') {y = 20*Bel(x) ;} else {y = 10*Bel(x);} }


function x_T()
{	
	y = r*(x-1)/(x+1);
	z = r*2*x/(x*x-1);
	vy1= "ohm (R1-2)"; vz1= "ohm (R3)"; return vy1, vz1;
}


function x_TT()
{	
	y = r*(x+1)/(x-1);
	z = r*(x*x-1)/(2*x);
	vy1= "ohm (R1-2)"; vz1= "ohm (R3)"; return vy1, vz1;
}

function x_mp()
{	if (r >x)	//Ri (r) > RL (x) 
	{
	y = r*Math.sqrt(1-(x/r));
	z = x/Math.sqrt(1-(x/r));
	vl = 1/(1- (Math.sqrt(1-x/r))); l = Math.round(2000*Bel(vl))/100;
	x = x + ' ohm ' + '	loss =' + l ; DispX();
	vy1= "ohm (Rs)"; vz1= "ohm (Rp)"; return vy1, vz1;
	}
	else		//Ri (r) < RL (x) 
	{z = x*Math.sqrt(1-(r/x));
	y = r/Math.sqrt(1-(r/x));
	vl = 1+ z/x; l = Math.round(2000*Bel(vl))/100;
	x = x + ' ohm ' + '	loss = ' + l ; DispX();
	vy1= "ohm (Rp)"; vz1= "ohm (Rs)"; return vy1, vz1;
	}

}


function Calcul(vy1,vz1)

{a = 0; y1= vy1; z1=vz1;

if (ww== 'Ra_dB')
	{Ra_dB();a=1;}

if (ww== 'dB_Ra')
	{dB_Ra();a=1;}

if (ww== 'Vm_Wm')
	{Vm_Wm();a=1;}

if (ww== 'Wm_Vm')
	{Wm_Vm();a=1;}


if (ww== 'V_A'){V_A();a=1;}
if (ww== 'V_W'){V_W();a=1;}
if (ww== 'V_dBV'){V_dBV();a=1;}
if (ww== 'V_dBmV'){V_dBmV();a=1;}
if (ww== 'V_dBuV'){V_dBuV();a=1;}
if (ww== 'V_dBuA'){V_dBuA();a=1;}
if (ww== 'V_dBm'){V_dBm();a=1;}


if (ww== 'A_V'){A_V();}
if (ww== 'A_W'){A_V();x=y;V_W();}
if (ww== 'A_dBV'){A_V();x=y;V_dBV()}
if (ww== 'A_dBmV'){A_V();x=y;V_dBmV()}
if (ww== 'A_dBuV'){A_V();x=y;V_dBuV();}
if (ww== 'A_dBuA'){A_V();x=y;V_dBuA();}
if (ww== 'A_dBm'){A_V();x=y;V_dBm();}


if (ww== 'W_V'){W_V();a=1;};
if (ww== 'W_A'){W_V();x=y;V_A();}
if (ww== 'W_dBV'){W_V();x=y;V_dBV();}
if (ww== 'W_dBmV'){W_V();x=y;V_dBmV();}
if (ww== 'W_dBuV'){W_V();x=y;V_dBuV()}
if (ww== 'W_dBuA'){W_V();x=y;V_dBuA();}
if (ww== 'W_dBm'){W_V();x=y;V_dBm();}


if (ww== 'dBm_V'){dBm_V();}
if (ww== 'dBm_A'){dBm_V();x=y;V_A();}
if (ww== 'dBm_W'){dBm_V();x=y;V_W();}
if (ww== 'dBm_dBV'){dBm_V();x=y;V_dBV();}
if (ww== 'dBm_dBmV'){dBm_V();x=y;V_dBmV();}
if (ww== 'dBm_dBuV'){dBm_V();x=y;V_dBuV();}
if (ww== 'dBm_dBuA'){dBm_V();x=y;V_dBuA();}


if (ww== 'dBuV_V'){dBuV_V();}
if (ww== 'dBuV_A'){dBuV_V();x=y;V_A();}
if (ww== 'dBuV_W'){dBuV_V();x=y;V_W();}
if (ww== 'dBuV_dBV'){dBuV_V();x=y;V_dBV();}
if (ww== 'dBuV_dBmV'){dBuV_V();x=y;V_dBmV();}
if (ww== 'dBuV_dBm'){dBuV_V();x=y;V_dBm();}
if (ww== 'dBuV_dBuA'){dBuV_V();x=y;V_dBuA();}


if (ww== 'dBmV_V'){dBmV_V();}
if (ww== 'dBmV_A'){dBmV_V();x=y;V_A();}
if (ww== 'dBmV_W'){dBmV_V();x=y;V_W();}
if (ww== 'dBmV_dBV'){dBmV_V();x=y;V_dBV();}
if (ww== 'dBmV_dBuV'){y=x+60; a=1;}
if (ww== 'dBmV_dBm'){dBmV_V();x=y;V_dBm();}
if (ww== 'dBmV_dBuA'){dBmV_V();x=y;V_dBuA();}


if (ww== 'dBuA_V'){dBuA_V();}
if (ww== 'dBuA_A'){dBuA_V();x=y;V_A();}
if (ww== 'dBuA_W'){dBuA_V();x=y;V_W();}
if (ww== 'dBuA_dBV'){dBuA_V();x=y;V_dBV();}
if (ww== 'dBuA_dBm'){dBuA_V();x=y;V_dBm();}
if (ww== 'dBuA_dBmV'){dBuA_V();x=y;V_dBmV();}
if (ww== 'dBuA_dBuV'){dBuA_V();x=y;V_dBuV();}

 
if (ww== 'dBV_V'){dBV_V();}
if (ww== 'dBV_A'){dBV_V();x=y;V_A();}
if (ww== 'dBV_W'){dBV_V();x=y;V_W();}
if (ww== 'dBV_dBmV'){y=x+60; a=1;}
if (ww== 'dBV_dBuV'){y=x+120; a=1;}
if (ww== 'dBV_dBm'){dBV_V();x=y;V_dBm();}
if (ww== 'dBV_dBuA'){dBV_V();x=y;V_dBuA();}


if (ww== 'dB_vs')
	{y=-x/10; y= Math.pow(10,y); x_vs();a=1;}

if (ww== 'Ra_vs')
	{y=x; x_vsb();a=1;}

if (ww== 'vs_dB')
	{vs_dB();a=1;}

if (ww== 'dB_mp')
	{x_mp();a=1;}

if (ww== 'dB_T')
	{y=x/20; x= Math.pow(10,y); x_T();a=1;}

if (ww== 'dB_TT')
	{y=x/20; x= Math.pow(10,y); x_TT();a=1;}

if (ww== 'Ra_T')
	{	if (br == 'P'){x=Math.sqrt(x);} 
	x_T();a=1;}

if (ww== 'Ra_TT')
	{	if (br == 'P'){x=Math.sqrt(x);}
	x_TT();a=1;}


if (a==0)
	{y= 'not available';}
}


//-->