bits2nec_nasa.m

在一个任意的天线方向图下

#!/usr/bin/octave -qH

% -q causes Octave to run in 'quiet' mode, -H prevents the commands we use
% from being added to Octave's command history.

% function for converting a string which represents a binary number into a binary number
% for speed we have no sanity checks. The number is read in the conventional sense (LSB on the RHS)

function num = strbin (str)
	num = 0;

	len = max (size (str));
	
	for i = 1:len
		num = num + (str (i) - '0') * bitshift (1, len - i);
	end
end

if (nargin < 1)
	fprintf (stderr, 'Usage: bits2nec_nasa.m <code> <code> <code>...\n');
	exit (-1);
end

max_length = 1;
n_wire_segments = 100;
diameter = 0.002;
displacement = 0.002;
frequency = 150;

for N = 0 : length (argv) - 1
	code = sscanf (nth (argv, N + 1), '%s');

	nbits = max (size (code));

	if mod (nbits, 24) ~= 0
		fprintf (stderr, 'Error: arguments must be a multiple of 24 bits (it is %i)\n', nbits);
		exit (-1);
	end

	nsegments = nbits / 24;

	FILE = fopen (sprintf ('/tmp/horiz_%i.nec', N), 'w');

	fprintf (FILE, 'CM Automatically-generated NEC script (from bits2nec_nasa_fast.m)\n');
	fprintf (FILE, 'CE\n');

	prev_p = [0; 0; 2 * displacement];

	for i = 0:nsegments - 1
		length = strbin (substr (code, 1 + i * 24, 8));

		if (length == 0)
			length = 1;
		end

		theta = strbin (substr (code, 9 + i * 24, 8));
		phi = strbin (substr (code, 17 + i * 24, 8));

		p = [length * max_length / 256; 0; 0] + prev_p;

% convert to radians
	
		theta = theta * pi / 256;
		phi = phi * 2 * pi / 256;

% Generate coordinate transformation matrices (rotation about z and y axis)

		tmatrix = [cos(theta), -sin(theta), 0; sin(theta), cos(theta), 0; 0, 0, 1]* [cos(phi), 0, sin(phi); 0 ,1, 0; -sin(phi), 0, cos(phi)];

		p = tmatrix * p;
	

		fprintf (FILE, 'GW %i %i %f %f %f %f %f %f %f\n', i + 1, n_wire_segments, prev_p (1), prev_p (2), prev_p (3), p(1), p(2), p(3), diameter);

		prev_p = p;
	end

	fprintf (FILE, 'GW %i 3 0 0 0 0 0 %f %f\n', nsegments, 2 * displacement, diameter);
	fprintf (FILE, 'GE\n');

	for i = 1 : nsegments
		fprintf (FILE, 'LD %i 1 0 0 3.767E+07\n', i);
	end

	fprintf (FILE, 'EX %i 3 1 0 100\n', nsegments);
	fprintf (FILE, 'FR 0 1 0 0 %f\n', frequency);
	fclose (FILE);

	system (sprintf ('cp /tmp/horiz_%i.nec /tmp/vert_%i.nec', N, N));

	FILE = fopen (sprintf ('/tmp/horiz_%i.nec', N), 'a');

	fprintf (FILE, 'RP 0 1 360 0000 90 0 0 1\n');
	fprintf (FILE, 'EN\n');

	fclose (FILE);

	FILE = fopen (sprintf ('/tmp/vert_%i.nec', N), 'a');

	fprintf (FILE, 'RP 0 360 1 0000 0 0 1 0\n');
	fprintf (FILE, 'EN\n');

	fclose (FILE);
end