Course Code: EEE 310 Course Title: COMMUNICATION SYSTEMS LAB Experiment No: 05 Experiment Title: Design and Study ASK signal using MATLAB. NURUJJAMAN SHAWN 163016016 SUBMITTED TO: TAMA FOUZDER SUBMISSION DATE: 1/5/2021 Objective: To generate amplitude shift keyed (ASK) signal using MATLAB. Theory: Amplitude Shift Keying (ASK) In amplitude shift keying, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remain constant while the amplitude changes. Binary ASK (BASK) Although we can have several levels (kinds) of signal elements, each with a different amplitude, ASK is normally implemented using only two levels. This is referred to as binary amplitude shift keying or on-off keying (OOK). The peak amplitude of one signal level is 0; the other is the same as the amplitude of the carrier frequency. Figure 1.1 gives conceptual views of binary ASK. Generation of ASK – Amplitude shift keying - ASK - is a modulation process, which imparts to a sinusoid two or more discrete amplitude levels. These are related to the number of levels adopted by the digital message. For a binary message sequence there are two levels, one of which is typically zero. The data rate is a sub-multiple of the carrier frequency. Thus the modulated waveform consists of bursts of a sinusoid. One of the disadvantages of ASK, compared with FSK and PSK, for example, and is that it has not got a constant envelope. This makes it’s processing (e.g., power amplification) more difficult, since linearity becomes an important factor. However, it does make for ease of demodulation with an envelope detector. Example MATLAB PROGRAM: clc; clear all; close all; t = 0:0.001:1; % Time duration for all signal A = 3; % Amplitude of the carrier signal fc = 12; % Frequency of the carrier signal fm = 3; % Frequency of the message signal message = A/2*square(2*pi*fm*t)+(A/2); % Message signal (Square wave) subplot(3,1,1) plot(t,message); xlabel('Time'); ylabel('Amplitude'); title('Square Wave'); grid on; carrier = A*sin(2*pi*fc*t); % Carrier signal subplot(3,1,2) plot(t,carrier); xlabel('Time'); ylabel('Amplitude'); title('Carrier Signal'); grid on; modulation = message.*carrier; subplot(3,1,3) plot(t,modulation); xlabel('Time'); ylabel('Amplitude'); title('ASK Signal'); grid on; Observation: Discussion: In this experiment we first take Amplitude and frequency of carrier and message signal then generate message signal for a digital signal then plot it. Again we generate a carrier signal and plot it and lastly we dot multiply message and carrier signal which we generate before and after dot multiplication we can call it modulated signal which is also called Amplitude shift keyed (ASK) signal.