Tutorials Status

[antoinet]

Hi,
I wonder about the status of the SDR/DSP tutorials. Can you already tell when they will be available?
Thanks and greetings from Switzerland,
Antoine

[bpadalino]

Hi Antoine,

We've been focusing on getting the hardware in a production state. With that being said, and the pre-production units coming in soon, it's a good time to start the discussion of what you'd like to see for tutorials.

I have thought about a simple introduction to complex baseband signals - what does it mean to represent a signal centered around 0Hz? What is a direct conversion RF receiver? What is a negative frequency?

Our first modulation tutorial was going to be either an introduction to analog modulations - Amplitude Modulation (AM) and Frequency Modulation (FM), followed by a simple tutorial on a very simple digital modulation scheme - Frequency Shift Keying (FSK).

Beyond that, it gets a little hazy. Most newer communication standards use OFDM to help combat the multipath fading channel. So would you rather see a tutorial on simulating Additive White Gaussian Noise (AWGN) channels, followed by a multipath fading channel tutorial? More digital modulations? Start digging into a standard?

What would you like to see?

Brian

[antoinet]

Thanks for the info. Since I'm pretty much a novice in RF technology, I'm very interested in introductory tutorials on signal basics and AM, FM and FSK. After that, I'd be interested in knowing more about digital modulation schemes like PSK, GMSK, etc before going on to OFDM. I'd also appreciate a discussion on some standards, for example GSM if suitable.

[bpadalino]

Sounds good. Let me know what you think of this type of progression with their respective summaries.

Signal Basics and Terminology
We introduce the concept of a complex baseband signal centered around 0Hz in the form of an in-phase and quadrature component (IQ). The unit circle, signal envelope, sampling theory, dynamic range, and a brief introduction to the wireless channel will be discussed as well as the need for bandwidth limiting signals.

Analog Modulations
Amplitude Modulation (AM), Phase Modulation (φM) and Frequency Modulation (FM) will be the focus of this chapter as well as their parameters and spectra. Implementation considerations for each will be introduced for both transmission and reception.

Basic Digital Modulations
Basic digital modulations will be introduced here such as On-Off Keying (OOK), Frequency Shift Keying (FSK) as well as Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM) and their differential variants. Focus will be on the transmission of these signals with some discussion regarding reception characteristics of each of the types of signals.

The Wireless Channel
We introduce the Additive White Gaussian Noise (AWGN) channel - the most basic, and build multipath and fading environments on top of this channel. Terminology such as Doppler spread, delay spread and frequency offset will be defined. Accurate simulation, power normalization and SNR will be discussed as well as the concept of "channel sounding" to find the impulse response of a wireless channel.

Radio Basics and Terminology
We introduce a few different architectures for radios: superheterodyne, homodyne (aka: direct conversion) and direct sampling. Gain, filtering, mixing spurs and frequency planning will all be discussed in the analog domain. The main focus of this chapter will be to emphasize the balance between digital and analog in the software defined radio world.

This is a lot of material to cover, but I'd love to get feedback as early as possible so as we write and develop these tutorials. Comments, questions and suggestions are all welcome!

Brian

[antoinet]

For my level of knowledge, the first 3 sections will definitevely be the most valuable. I'm also looking forward for the succeeding tutorials, but since at this moment, I lack understanding for the material, I can't judge if its valuable or not.

[bpadalino]

Thanks for your feedback! I'll be sure to work on those as soon as possible and get them published to the site.

[madengr]

I'd like to see carrier tracking and clock recovery for PSK in GNU radio. Perhaps a QPSK TX loop-back to RX.

[bpadalino]

If you're looking for a specific implementation in GNU Radio, you may want to check out the M&M Clock Recovery Block.

I am not sure how well it works at low SNR, but at higher SNR I believe it should work pretty well. CPU wise, on the other hand, it might be somewhat intensive? I am also not sure how well it works in a multipath environment.

Do you have any specific use cases you're looking at? Burst or constant transmission?

[lousyg]

It's been about 3 months since the last post here, and I thought I'd check in to see what the status of some tutorials and examples are.

I'm about as "newb" as you can get when it comes to SDR (or even RF for that fact). I'm very eager to start using the BladeRF but don't really know where to begin.

Thanks!

[bpadalino]

The tutorials are slow going right now. We are currently prioritized on getting the software solid and getting platforms up and running. We focused hard on linux, and not it's time to bring libusb into the fold and get Windows and OSX support. Native Windows and OSX drivers will come later, but right now libusb should do well enough.

As for reading you can do right now, you may want to check the Complex to Real Blog, Daniel Lyons book Understanding Digital Signal Processing or the DSP Guide.

I also encourage you to ask questions here as you come to them. I also encourage to post ideas or questions on what you'd like to do - digital or analog modulation techniques? Radio Astronomy? RADAR? The best learning happens when there is an end goal in mind.

[rthorntn]

Holy cow, if RADAR is possible with BladeRF, I would love a tutorial on that!

[j0henz]

This might be more on the advanced side of things, but here are some literature on OFDM:
http://www.eit.lth.se/fileadmin/eit/cou ... 3_v206.pdf

It deals with channel estimation/equalization, synchronization, coding etc. in OFDM.

[bpadalino]

Nice!

That OFDM tutorial has lots of good tidbits in it. Very good stuff.

Thanks!