[SOLVED] Suggestion regarding Demodulation

Hi,

I am new to Digital Communications and MATLAB. I am learning to implement modulations and demodulations in MATLAB.

I have an amplitude modulated signal at the receiver input. I am trying to recover the message bits after the demodulation.

Following are the parameters of the modulated signal:
Carrier frequency = 22000 Hz (can be +/- 2000 Hz)

To decode the bits, the logic is that, if the width of the pulse is more then its 1 else 0.

I tried the following at the receiver:
1. Mixed the incoming signal with a locally generated 22000 Hz carrier.
2. Passed the signal through a Low Pass Filter with Fp = 2000Hz, Fs = 3000Hz
3. Obtained the envelope of the LPF output.

Can anyone please let me know if what I have done is correct?

Following are the waveforms at each stage:

Please suggest what steps to follow to decode the message bits.

Thanks,
Suma