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Transmitting audio using 4-qam modulation

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electroRF

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Hi,
I'd like to start off with a project of transmitting and receiving audio signal using 4-QAM modulation.
(Later, I'd move to transmitting pictures and video, therefore I'd like to use 4-QAM).

The blocks would be:

Microphone ---> PIC ---> QAM Modulator ---> Transmitter ---------> Receiver ---> QAM Decoder ---> PIC ---> Speaker

I'd like to avoid doing by myself the FFT in the PIC.

Should I use additional module between the PIC and the QAM Modulator, that will perform the FFT and pass it to the QAM Modulator?

Thank you.
 
Hi,
I'd like to start off with a project of transmitting and receiving audio signal using 4-QAM modulation.
(Later, I'd move to transmitting pictures and video, therefore I'd like to use 4-QAM).

The blocks would

Microphone ---> PIC ---> QAM Modulator ---> Transmitter ---------> Receiver ---> QAM Decoder ---> PIC ---> Speaker

I'd like to avoid doing by myself the FFT in the PIC.

Should I use additional module between the PIC and the QAM Modulator, that will perform the FFT and pass it to the QAM Modulator?

Thank you.

Why FFT ?
You don't need FFT to transmit audio or do you mean ADC ?
 
Hi jjw.

In the near future, I'd like to transmit Video as well, and for that I'll need to use 4-QAM Modulation.

In order to generate the I and Q signals, I'll need to perform FFT.
 
In order to generate the I and Q signals, I'll need to perform FFT.

No you don't. FFTs (even DFTs) can be heavy in terms of CPU usage. Look at an analogue IQ generator and work out how to do this in a CPU.

It's not that difficult if you have enough RAM available.

Video BTW is even more demanding and dedicated video processors maybe required.
 
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