Super-heterodyne Receiver

Project Description

• The purpose of this project is to simulate the basic components of an analog communication system using MATLAB programming. Specifically, an AM modulator and a corresponding super-heterodyne receiver will be simulated using radio-station generated signals.

Contents

• Audio Signals : audio signals that used during testing
• Screens : output figures
• Source Code : MATLAB file

Project Requirements

• MATLAB program recommended version 2021

Block Diagram

Result Figures

Removing RF stage

%%%%%%%%%% comment this part if you want to demodulate without RF stage %%%%%%%%%%
% sum_signals_BPF = sum_signals;
band_pass_filter = fdesign.bandpass(F_stop1, F_pass1, F_pass2, F_stop2, A_stop1, A_pass, A_stop2, 15 * Fs);
band_pass_filter = design(band_pass_filter, 'equiripple');
sum_signals_BPF = filter(band_pass_filter, sum_signals);
SUM_SIGNALS_BPF = fftshift(fft(sum_signals_BPF));
f_MODULATED_SIGNAL = (-length(SUM_SIGNALS_BPF) / 2:1:length(SUM_SIGNALS_BPF) / 2 - 1)';
subplot(2, 1, 2)
plot(f_MODULATED_SIGNAL * Fs_carrier / length(SUM_SIGNALS_BPF), abs(SUM_SIGNALS_BPF), 'r')
title("RF stage after BPF for audio " + choose_signal)
xlabel("Frequency (Hz)")
ylabel("Magnitude")
grid on

Offset in Receiver Oscillator frequency

%%%%%%%%%% the receiver oscillator offset [0, 0.1k, 1k] %%%%%%%%%%
offset = 0;
IF = 25000 + offset;                                % If frequency 25 KHz

Run Program

• by running code, user required to choose which audio he want to hear as in the following figure

Team members

• Omr Amr Mahmoud Hafez
• Mohamed Khaled Mohamed Alahmady