I am a student. I want to learn about Software Defined Radio to build a Reader for Saw tag and simulate them on Matlab/Simulink.

These bocks below is what I want to build in Matlab/Simulink enter image description here

I found I could simulate RF front-end block using AD9361 because they are supported by Analog Device.

And I want to ask, can I build the digital blocks of Tx/Rx side and connect it to Tx/Rx AD9361 model to run the loop-back test like this (connect Rx to Tx) ? enter image description here


You probably can. But: the AD9361 is definitely a complex beast, and I honestly think you're setting yourself up for more trouble than your solving when using a model of a device with a couple thousand different settings.

Unless you're planning to build an SDR out of an actual AD9361, I'd recommend not using them in a simulation. It's probably among the most complex models available in Simulink!

You shouldn't be building your own SDR, but rather buy one; as far as I remember, these typically need relatively high bandwidth, and designing the digital side of a PCB that carries multiple Megasamples of complex data per second into your computing unit will not be a beginner's project (aside from being far more expensive to buy and manufacture in single digit quantities than just buying a commercially available SDR).

The question really is whether you need to have a simulation that incorporates the actual SDR hardware – wouldn't for a very long time a simple idealized (IQ) mixer be representative enough? Aren't you starting off at the wrong end by trying to model something that works quite close to ideal very intimately instead of trying to get a system understanding based on idealized models?

For example, your flow graph top row isn't correct, to be honest. You used "QAM modulation" for what should be a quadrature modulator (QAM modulation is a baseband symbol mapping method, not a "modulation" as in "shift of frequency").

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  • $\begingroup$ Thank you. I agree with you, my figure is wrong at Q-AM Modulation. It's the symbol mapping method. $\endgroup$ – Thanh niên Yên Bái Dec 5 '18 at 9:19
  • $\begingroup$ As I said, I want to build a Reader for the wireless sensor using SDR technology. So I need to understand the parameters of each block, how it work, the waveform from input to output. I know it's quite complex due to so many parameters it has. So building a total block in it with the AD9361 model on matlab/simulink that is only way I can do. Do you have any suggestions for me ? $\endgroup$ – Thanh niên Yên Bái Dec 5 '18 at 9:33
  • $\begingroup$ no, it's not the only way you can go, as my answer explained: we use simpler models of reality when these models are realistic enough. In your case, simply considering the SDR device as Quadrature Mixer and amplifier would really suffice. $\endgroup$ – Marcus Müller Dec 5 '18 at 10:39

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