%% ECE214 Lab #5 Low Pass Filter Design (Spring 2024)

%% Copyright (c) 2024 by David E. Kotecki. All rights reserved.

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%% Section 1: Define: CPPSim location, library, and schematic
clear variables;
% CppSim_Location = sprintf('C:/CppSim'); % location of CppSim directory
% Design_Library = sprintf('Library Name'); % name of design library
% Schematic_Name = sprintf('Schematic Name'); % name of schematic

CppSim_Location = sprintf('/Users/david/CppSim'); % location of CppSim directory
Design_Library = sprintf('ECE214_2024'); % name of design library
Schematic_Name = sprintf('Lab5_filter_test_2024'); % name of schematic

%% Section 2: Generate HSPC file and run NGspice
addpath(sprintf('%s/CppSimShared/HspiceToolbox', CppSim_Location)); % add ngspice matlab toolbox to the path
Working_Dir = sprintf('%s/SimRuns/%s/%s', CppSim_Location, Design_Library, Schematic_Name);
if ~exist(Working_Dir, 'dir')  
    mkdir(Working_Dir)  % create working directory if it does not exist
end
cd(Working_Dir) % set current folder to the working directory
hspc_filename = sprintf('%s.hspc', Schematic_Name);   % define hspc filename

hspcfile = fopen(hspc_filename, 'w');    % open file 'hspc_filename' for write
fprintf(hspcfile, '**** NGspice HSPC file **** \n');
fprintf(hspcfile, '**** File: %s/%s **** \n', pwd, hspc_filename);
fprintf(hspcfile, '**** Date: %s **** \n\n', datestr(datetime('now')));

fprintf(hspcfile, '**** Simulation Statement ****\n');
fprintf(hspcfile, '.tran 100u 125m 25m 0 \n\n');

fprintf(hspcfile, '**** Paramenter Statements ****\n');
fprintf(hspcfile, '.param res1 = 20 \n');   % define resistor value res1
fprintf(hspcfile, '.param res2 = 20 \n');   % define resistor value res2 
fprintf(hspcfile, '.param cap1 = 20 \n');  % define resistor value cap1
fprintf(hspcfile, '.param cap2 = 20 \n\n');  % define resistor value ?ap2
ECE214_2024_Lab5_parameters;

fprintf(hspcfile, '**** Include Statements ****\n');
fprintf(hspcfile, '.include ../../../SpiceModels/ECE214_models.mod \n\n');

fprintf(hspcfile, '**** Simulation Options ****\n');
fprintf(hspcfile, '.options post=1 delmax=5p relv=1e-6 reli=1e-6 relmos=1e-6 method=gear \n');
fprintf(hspcfile, '.temp 27\n');
fprintf(hspcfile, '.global gnd \n');
fprintf(hspcfile, '.op \n\n');
fprintf(hspcfile, '**** End of NGspice hspc file \n');
fclose(hspcfile);
 
ngsim(hspc_filename); % run ngspice  

%% load simulation results and extract time, Vout, and Vin
data = loadsig('simrun.raw');  % load data from simulation into Matlab
time = evalsig(data, 'TIME');  % create vector of time values
Vin = evalsig(data, 'vin');    % create vector of node vin voltage values
Vout = evalsig(data,'vout');   % create vector of node Vout voltage values

%% plot Vin and Vout as a function of time
fs = 16; % define font size
lw = 1.5; % define linewidth
Fig1 = figure('Position', [200, 75, 850, 600]); % figure size and location

subplot(2,1,1); % first subplot
plot(time.*1000,  Vin, 'linewidth',lw);
grid on; % add grid
set(gca, 'fontsize', fs); % set font size
ylabel('Voltage (V)', 'fontsize', fs); % label y-axis
title('ECE 214: Lab 5 - Low Pass Filter (time domain)'); % title
legend('Filter Input'); % add legend
axis([35 40 -2 2]); % set axis limits

subplot(2,1,2); % second subplot
plot(time.*1000, Vout, 'linewidth',lw);
grid on; % add grid
set(gca, 'fontsize', fs); % set font size
xlabel('Time (ms)', 'fontsize', fs); % label x-axis
ylabel('Voltage (V)', 'fontsize', fs); % label y-axis
legend('Filter Output'); % add legend
axis([35 40 -2 2]); %set axis limits

%return
%% Plot the FFT (Approximate Fourier Series)
Fig2 = figure('Position', [150, 75, 850, 600]); % figure size and location

subplot(2,1,1);
[freq, mag_in] = vt_to_vf(time, Vin); % generate Fourier components
semilogx(freq, mag_in, 'linewidth', lw);
grid on;
set(gca, 'fontsize', fs);
axis([100,1e5,-30,10]); % set axis limits
legend('Filter Input'); % add legend
ylabel('Voltage (dB)', 'fontsize', fs); % label y-axis
title('ECE 214: Lab 5 - Low Pass Filter (Fourier components of square wave)')

subplot(2,1,2);
[freq, mag_out] = vt_to_vf(time, Vout); % generate Fourier components
semilogx(freq, mag_out, 'linewidth', lw);
grid on;
set(gca, 'fontsize', fs);
axis([100,1e5,-40,10]);
legend('Filter Output'); % add legend
ylabel('Voltage (dB)', 'fontsize', fs); % label y-axis
xlabel('Frequency (Hz)', 'fontsize', fs); % label x-axis

% return
%% Read measured data into Matlab
% AD2_data = readtable('/Users/david/Dropbox/Waveforms_data/lab5_data.csv', 'NumHeaderLines', 30);
% AD2_data.Properties.VariableNames = {'freq', 'mag1', 'mag2', 'ph'};
% meas_f = AD2_data.freq;
% meas_m = AD2_data.mag2;
% meas_p = AD2_data.ph;

%% Post Lab - Frequency response of Low Pass Filter (ac analysis)
% set the AC_Voltage = 1 volt in the schematic
hspc_addline('.ac dec 201 100 1e5', hspc_filename); % change from transient to ac analysis
ngsim(hspc_filename); % run NGspice

%% Load simulation results and extract Frequency and Vout
data = loadsig('simrun.raw');
frequency = evalsig(data, 'FREQUENCY');
Vout = evalsig(data,'vout');

%% Plot amplitude and phase

Fig3 = figure('Position', [100, 75, 850, 600]);

subplot(2,1,1)
semilogx(frequency, 20.*log10(abs(Vout)), 'linewidth',lw);
grid on;
set(gca, 'fontsize', fs);
ylabel('dB Voltage', 'fontsize', fs);
title('ECE 214: Lab 5, Low Pass Filter (frequency response)');

% hold on
% semilogx(meas_f, meas_m, 'linewidth', lw);
% legend('Simulated Magnitude', 'Measured Magnitude'); % add legend

subplot(2,1,2)
semilogx(frequency, angle(Vout).*180/pi, 'linewidth',lw);
grid on;
set(gca, 'fontsize', fs);
xlabel('Frequency (Hz)', 'fontsize', fs);
ylabel('Phase (degrees)', 'fontsize', fs);

% hold on
% semilogx(meas_f, meas_p, 'linewidth', lw);
% legend('Simjulated Phase', 'Measured Phase'); % add legend

%% end of .m file