#### EE342.01: MATLAB M-FILE FOR PLOTTING A DISCRETE-TIME
SIGNAL

**MATLAB M-File payments.m:**
%
% Filename: payments.m
%
% Description: This matlab m-file computes monthly loan payments
% given the amount borrowed, the number of months
% financed, and the annual interest rate. It then
% plots the principle and payments as a discrete-time
% signal.
%
P = input('Enter amount borrowed: ');
N = input('Enter number of months financed: ');
iy = input('Enter the annual interest rate in percent: ');
im = iy/(12*100); % compute monthly interest rate
% not in percent
A = P*((im*(1+im)^N)/((1+im)^N-1)); % compute payment amounts
n = 0:N; % define time periods (months here)
CF = [P -A*ones(1,N)]; % compute discrete-time signal
% representing cash flow
stem(n,CF); % plot cash flow as a discrete-time
% signal
xlabel('n'); % label plots
ylabel('cash flow');
title('Plot of Loan Cash Flow');

**Run payments.m by typing payments at the matlab prompt
after saving it in a working directory: **
>> payments
Enter amount borrowed: 1000
Enter number of months financed: 12
Enter the annual interest rate in percent: 16.9

**MATLAB Plot Generated:**

The plot was printed by typing 'print' at the matlab
prompt when the plot was displayed in the graphics window.