// GMRT Receiver Tuning for GWB //
// snk Jan2023 //

	var line;
	var rf_band;
	var b1,b2;
	var gab_bw;
	var gab_lo;
	var gwb_bw;
	var ddc_lo;

// init onload/reset 
function init(){
	"use strict";

	document.getElementById("line").value=1420.1234;
	document.getElementById("rf_band").value="50";
	document.getElementById("ddc_lo").value=0;
	get_default("gab_bw");
	get_default("gab_lo");
	get_default("band_range");
	plot();
}


// plot on server and get the image
function plot() {
	"use strict";
	// read input parameters
	if(document.getElementById("line").value == "") { line="NA"; }  
	else { line=parseFloat(document.getElementById("line").value); } 	

	rf_band=document.getElementById("rf_band").value;
	gab_bw=document.getElementById("gab_bw").value;
	gab_lo=document.getElementById("gab_lo").value;
	gwb_bw=document.getElementById("gwb_bw").value;
	ddc_lo=document.getElementById("ddc_lo").value;
	//image display 
	document.getElementById("image").src="./tune.php?para="+line+" "+rf_band+" "+b1+" "+b2+" "+gab_bw+" "+gab_lo+" "+gwb_bw+" "+ddc_lo;
}

// cheak all input para
function check(arg) { 
	"use strict";

	if(arg == "line") { 
	plot();
	}

	if(arg == "rf_band") { 
	get_default("gab_bw");
	get_default("gab_lo");
	get_default("band_range");
	plot();
	}

	if(arg == "gab_bw") { 
	plot();
	}

	if(arg == "gab_bw_def") { 
	get_default("gab_bw");
	plot();
	}

	if(arg == "gab_lo") { 
	plot();
	}

	if(arg == "gab_lo_m") { 
	document.getElementById('gab_lo').value--;
	plot();
	}

	if(arg == "gab_lo_p") { 
	document.getElementById('gab_lo').value++;
	plot();
	}

	if(arg == "gab_lo_def") { 
	get_default("gab_lo");
	plot();
	}

	if(arg == "ddc_lo") { 
	plot();
	}

	if(arg == "ddc_lo_m") { 
	ddc_lo=document.getElementById('ddc_lo').value;
	ddc_lo=ddc_lo-1;if(ddc_lo < 0 ) { ddc_lo=0; }
	document.getElementById('ddc_lo').value=ddc_lo;
	plot();
	}

	if(arg == "ddc_lo_p") { 
	ddc_lo=parseFloat(document.getElementById('ddc_lo').value);
	ddc_lo=ddc_lo+1.0;if(ddc_lo > gab_bw-gwb_bw) { ddc_lo=gab_bw-gwb_bw; }  
	document.getElementById('ddc_lo').value=ddc_lo;
	plot();
	}

	if(arg == "ddc_lo_def") { 
	document.getElementById("ddc_lo").value=0;
	plot();
	}

	if(arg == "cal") { 
	auto_cal();
	plot();
	}

}

function auto_cal() { 
	"use strict";

                // read inputs 
		line=parseFloat(document.getElementById("line").value); 
		gab_bw=parseInt(document.getElementById("gab_bw").value);
		gab_lo=parseInt(document.getElementById("gab_lo").value);
		gwb_bw=parseFloat(document.getElementById("gwb_bw").value);

		if(isNaN(line)) { alert("Warning: Line frequency value is not correct"); } 
		if(line < b1 || line > b2 ) { alert("Warning: Line frequency is out of the selected band range"); }
		if(gwb_bw > gab_bw) { alert("Warning: GAB(final) band width should not greter than the GAB band width"); } 

		// calculate net sign
		var net;
		if(gab_lo < (b1+b2)/2 ) { net=1; } else { net=-1; } 

                var f1=line-(gwb_bw/2)*net;
                var f3=line+(gwb_bw/2)*net;
                var ff1=gab_lo;
                var ff3=gab_lo+gwb_bw*net;
		if(net == -1) { ddc_lo = ff1-f1; }  
		if(net == 1 ) { ddc_lo = f1-ff1; }  

		if(ddc_lo < 0) { 
		alert("Warning: Not possible to tune the line at the center of the GWB band. You may slide the GAB LO"); 
		ddc_lo=0;
		ddc_lo=ddc_lo.toFixed(4);
		document.getElementById("ddc_lo").value=ddc_lo;
		return;
		} 

		if((ddc_lo+gwb_bw) > gab_bw ) { 
		alert("Warning: Not possible to tune the line at the center of the GWB band. You may slide the GAB LO"); 
		ddc_lo=gab_bw-gwb_bw;
		ddc_lo=ddc_lo.toFixed(4);
		document.getElementById("ddc_lo").value=ddc_lo;
		return;
		} 

		ddc_lo=ddc_lo.toFixed(4);
		document.getElementById("ddc_lo").value=ddc_lo;
		return;
}

function get_default(arg) { 
	"use strict";

	// default band width values
	if(arg == "gab_bw") { 
	document.getElementById('gab_bw').value=100;
	if(document.getElementById('rf_band').value == "20") { document.getElementById('gab_bw').value=200; } 
	if(document.getElementById('rf_band').value == "30") { document.getElementById('gab_bw').value=200; } 
	if(document.getElementById('rf_band').value == "40") { document.getElementById('gab_bw').value=200; } 
	if(document.getElementById('rf_band').value == "50") { document.getElementById('gab_bw').value=400; } 
	}

	// default gab_lo values
	if(arg == "gab_lo") { 
	if(document.getElementById('rf_band').value == "20") { document.getElementById('gab_lo').value=300; } 
	
	if(document.getElementById('rf_band').value == "30") { document.getElementById('gab_lo').value=500; } 
	if(document.getElementById('rf_band').value == "31") { document.getElementById('gab_lo').value=340; } 
	if(document.getElementById('rf_band').value == "32") { document.getElementById('gab_lo').value=410; } 
	if(document.getElementById('rf_band').value == "33") { document.getElementById('gab_lo').value=460; } 
	if(document.getElementById('rf_band').value == "34") { document.getElementById('gab_lo').value=520; } 
	
	if(document.getElementById('rf_band').value == "40") { document.getElementById('gab_lo').value=550; } 
	if(document.getElementById('rf_band').value == "41") { document.getElementById('gab_lo').value=550; } 
	if(document.getElementById('rf_band').value == "42") { document.getElementById('gab_lo').value=635; } 
	if(document.getElementById('rf_band').value == "43") { document.getElementById('gab_lo').value=820; } 
	if(document.getElementById('rf_band').value == "44") { document.getElementById('gab_lo').value=900; } 
	
	if(document.getElementById('rf_band').value == "50") { document.getElementById('gab_lo').value=1460;} 
	if(document.getElementById('rf_band').value == "51") { document.getElementById('gab_lo').value=1120;} 
	if(document.getElementById('rf_band').value == "52") { document.getElementById('gab_lo').value=1230;} 
	if(document.getElementById('rf_band').value == "53") { document.getElementById('gab_lo').value=1340;} 
	if(document.getElementById('rf_band').value == "54") { document.getElementById('gab_lo').value=1450;} 
	}

	// default band start_stop values 
	if(arg == "band_range") { 
	if(document.getElementById('rf_band').value == "20") {   b1=100;  b2=300;  } 
	
	if(document.getElementById('rf_band').value == "30") {   b1=220;  b2=500;  } 
	if(document.getElementById('rf_band').value == "31") {   b1=240;  b2=340;  } 
	if(document.getElementById('rf_band').value == "32") {   b1=300;  b2=410;  } 
	if(document.getElementById('rf_band').value == "33") {   b1=360;  b2=460;  } 
	if(document.getElementById('rf_band').value == "34") {   b1=420;  b2=520;  } 
	
	if(document.getElementById('rf_band').value == "40") {   b1=550;  b2=950;  } 
	if(document.getElementById('rf_band').value == "41") {   b1=550;  b2=650;  } 
	if(document.getElementById('rf_band').value == "42") {   b1=635;  b2=735;  } 
	if(document.getElementById('rf_band').value == "43") {   b1=720;  b2=820;  } 
	if(document.getElementById('rf_band').value == "44") {   b1=800;  b2=900;  } 
	
	if(document.getElementById('rf_band').value == "50") {   b1=950;  b2=1460; } 
	if(document.getElementById('rf_band').value == "51") {   b1=1000; b2=1120; } 
	if(document.getElementById('rf_band').value == "52") {   b1=1110; b2=1230; } 
	if(document.getElementById('rf_band').value == "53") {   b1=1220; b2=1340; } 
	if(document.getElementById('rf_band').value == "54") {   b1=1330; b2=1450; } 
	}

}