loss_calculations.m

gistfile1.matlab

function watts = dBm2watts( dBm )
  watts = 10^-3*10.^(dBm/10);
endfunction

function [loss_min loss_max] = loss_per_meter( meters )
  loss_min = meters*.19;
  loss_max = meters*.43;
endfunction

function [loss_min loss_max] = loss_per_bulkhead( bulkheads )
  loss_min = .7*bulkheads;
  loss_max = 2.8*bulkheads;
endfunction

function [loss_min loss_max] = system_loss( meters, bulkheads )
  [loss_m_min loss_m_max] = loss_per_meter( meters );
  [loss_b_min loss_b_max] = loss_per_bulkhead( bulkheads );
  loss_min = loss_m_min + loss_b_min;
  loss_max = loss_m_max + loss_b_max;
endfunction

function [OPB] = calculateOPB( PTmin, PLmin)
  OPB = PTmin - PLmin;
endfunction

function [ROPB] = calculateROPB( OPB, loss_max, power_margin)
  ROPB = OPB - (loss_max+power_margin);
endfunction

function [amt_of_decrease] = calcDecrease(PTmax, PLmax, loss_min)
  amt_of_decrease = (PTmax - loss_min) - PLmax;
endfunction

% Set the min and max values for the Transmitter/Receiver Pair
PL_min = -39;
PL_max = -13.7;
PH_max = -53;
PT_min = -13.6;
PT_max = -4.5;
bulkheads = 0;
% Generate a vector of meters
meters = 0:5:40;
power_margin = 0;

% Calculate the min and max total system loss
[sys_loss_min sys_loss_max]= system_loss( meters, bulkheads);
% Calculates the Optical Power Budget (OPB)
OPB = calculateOPB( PT_min, PL_min );

% Calculates the Remaining OPB (ROPB) for each length of link 
% This will function as the minumum power
ROPB = zeros(1, numel(sys_loss_max));
for loss = 1:numel(sys_loss_max)
  ROPB(loss) = calculateROPB( OPB, sys_loss_max(loss), power_margin );
endfor

% Calculate the amount of decrease
% This will function as the maximum power
amt_of_decrease = zeros(1, numel(sys_loss_min));
for loss = 1:numel(sys_loss_min)
  amt_of_decrease(loss) = calcDecrease(PT_max, PL_max, sys_loss_min(loss));
endfor

% Plot in terms of dB
%subplot(1,3,1)
plot(meters, -amt_of_decrease, 'r-')
hold on
plot(meters, -ROPB, 'b-')
title('Power (dB) vs Length')
legend('Line of Max Current','Line of Min Current')
xlabel('Length of Link (m)')
ylabel('Output Power (dB)')

print('-dpng','current_analysis.png')

a = find(meters == 30);
fprintf('%d meters: %.2f, %.2f\n',meters(a),amt_of_decrease(a), ROPB(a))
input('');