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Help me build a Digital AM Receiver in Simulink

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Nosheen

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kindly help me build "Digital AM Receiver" in simulink, clearly identifying each block with paremeters....

help plz...
its urgent

regardz
Nosheen
 

m_mir

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attention plz...

at first you have to sample the incoming signal(or simulate the samples of it) then you should filter this sample to suppress the outband noise then you can estimate the carrier frequency and mix the filtered signal with the estimated carrier and pass the result from a lowpass filter with sufficient bandwidth the output would be the message. another way is to use hilbert transform to change the real signal into a complex form. magnitude of this complex signal is the message.
 

    Nosheen

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mowgli

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Re: attention plz...

If your inputs are the I and Q samples of the base band AM signal the receiving chain of a digital AM receiver could be designed as follows:

stage 1: input filter for band selection and adjacent channel rejection. The same filter shall be applied to I and Q samples.

stage 2: AM demodulator. This block performs the calculation of
Dem = sqrt(I^2 + Q^2).

stage 3: dc component extraction and normalization. This block extracts (Low pass filter) the dc component from the demodulator output, then performs the calculation of the normalized output samples
Norm = Dem / dc

stage 4 (optional): output band filtering. Filter Norm samples to eliminate out of band components from the normalized demodulated signal (e.g 300 Hz to 3500 Hz band is adequate for voice applications).

You can simulate this in Matlab/Simulink and you can even implement it in a C program and compile it for different targets (DSPs or GPPs).

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Mowgli
 

    Nosheen

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Nosheen

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attention plz...

dear Mowgli...
ur reply has helped me alot...M really grateful.
i want to know that how wod i get the I and Q samples of the required baseband AM signal???

waiting 4 ur reply soon
Regardz
Nosheen
 

mowgli

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Re: attention plz...

Assuming f the channel frequency and T the sampling period of your analog signal s(t)

I(nT) = s(nT) * cos( n2ΠfT )
Q(nT) = s(nT) * sin( n2ΠfT )

and then low pass filter the sequence I(n) and Q(n).

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Mowgli
 

    Nosheen

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Nosheen

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attention plz...

thanx again dear Mowgli..

Now plz tel me that the above mentioned four stages r just enough 4 my design and implementation of the "Digital AM Receiver"??

Infact my aim is to eliminate the IF Stages, using sampling techniques and directly extracting the required audio band for my Digital Receiver..W hat do u suggest is it the right approach??

secondly will Tree Based Filter Bank approach help me regarding my project??

thirdly I m looking for channel multiplexing in MATLAB/SIMULINK...how will it help in this project?

I'll b really grateful if YOU and other honourable forum members help me out...

waiting for reply soon

Regardz
Nosheen
 

Nosheen

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Re: attention plz...

Nosheen said:
thanx again dear Mowgli..

Now plz tel me that the above mentioned four stages r just enough 4 my design and implementation of the "Digital AM Receiver"??

Infact my aim is to eliminate the IF Stages, using sampling techniques and directly extracting the required audio band for my Digital Receiver..W hat do u suggest is it the right approach??

secondly will Tree Based Filter Bank approach help me regarding my project??

thirdly I m looking for channel multiplexing in MATLAB/SIMULINK...how will it help in this project?

I'll b really grateful if YOU and other honourable forum members help me out...

waiting for reply soon

Regardz
Nosheen
 

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