Carrier Synchronization Code for AM Modulation

i am trying to develop the code for carrier Synchronization in Amplitude Modulation(AM).

Does anybody have anyidea how to develop this code ?

Does anybody have pdf to follow the process to implement the algorithm ?

Does anybody have any code to do it ?

Answer 1

[Hari]

Hi Hari,

I understand that you are looking to develop code for carrier synchronization in Amplitude Modulation (AM) and are seeking guidance or resources to implement this algorithm.

In order to develop carrier synchronization for AM modulation, you can follow the below steps:

Generate AM Signal:

Create a modulated AM signal using a known carrier frequency.

fs = 1000; % Sampling frequency
fc = 100; % Carrier frequency
t = 0:1/fs:1-1/fs; % Time vector
x = cos(2*pi*10*t); % Message signal
amSignal = (1 + x) .* cos(2*pi*fc*t); % AM signal

Add Noise (Optional):

Introduce noise to the signal to simulate real-world scenarios.

noisySignal = amSignal + 0.1*randn(size(amSignal)); % Additive white Gaussian noise

Estimate Carrier Frequency:

Use techniques like the "fft" to estimate the carrier frequency from the received signal.

Y = fft(noisySignal);
[~, idx] = max(abs(Y));
estimatedFc = (idx-1) * fs / length(Y); % Estimate carrier frequency

Carrier Recovery:

Generate a synchronized carrier using the estimated frequency.

recoveredCarrier = cos(2*pi*estimatedFc*t); % Synchronized carrier

Demodulate the Signal:

Use the synchronized carrier to demodulate the AM signal.

demodulatedSignal = noisySignal .* recoveredCarrier;
demodulatedSignal = lowpass(demodulatedSignal, fc, fs); % Low-pass filter

Refer to the documentation of "fft" function for more information: https://www.mathworks.com/help/matlab/ref/fft.html

Refer to the documentation of "lowpass" function for filtering details: https://www.mathworks.com/help/signal/ref/lowpass.html

Hope this helps!