Learn SDR 04: What's Inside an SDR: Designing one from First Principles

Learn SDR with Professor Jason Gallicchio at Harvey Mudd College
Lesson 4: What's inside the SDR? Designing one from first principles. Zero-IF Direct Conversion
Incoming real RF signal is r(t)
This gets split, multiplied by cos and sin, low-pass filtered, sampled, and returned as a sequence of complex numbers.
r(t) = A cos(2πft+ϕ) turns into z(t) = A e^iϕ e^(2π(f-f0)t)
If I were to do it again, I'd draw more pictures of the RF waveform.
HW1: Do the trig identities to trace through the direct conversion architecture.
Extra Credit : Design a transmitter by reversing the process:
Turn z(t) = A e^iϕ e^(2πft) into r(t) = A cos(2π(f+f0)t+ϕ)
gallicchio.git...
All GNURadio flowgraphs are at:
github.com/gal...
--- Learn SDR with Professor Jason Gallicchio

[@pouyanebrahimbabaie5811]

Absolutely amazing video!! Thank you very much

[@anthony3604]

This channel is the BEST, thank you very much

[@heiri3ii337]

Thanks

[@preuton]

I was confused with the analogue way. For example de IF of FM is 10.7Mhz. With SDR there is no IF but the sidebands are direct available after mixing. Is this correct?

[@miltonriosj.1320]

Let's say that with SDR there is IF but it is zero and of course appears a negative frequency another way to get this is that the IF is shifted to zero intead of 10.7Mhz, this is so, to make easier to the processing algorithms to do the demodulation process.

[@aubreysaunders2381]

🙃 Pᵣₒmₒˢᵐ