New Analog Devices SDR stuff! Software defined radio is really moving fast!

[Smokey]

I can't believe sometimes how fast the SDR technology is moving.  It wasn't long ago that the USRP was really the only game in town.

I just got this Analog devices email going over their new SDR stuff.  It's really pretty amazing.
70MHz to 6GHz, with 200kHz to 56MHz bandwidth!

http://www.analog.com/static/imported-files/overviews/Software-Defined-Radio-Solutions-From-ADI.pdf

[tonyarkles]

Pretty sure that's the chip used in the Ettus B200 SDR. https://www.ettus.com/product/details/UB200-KIT

I just got mine in the mail a few weeks ago and haven't had much of an opportunity to play with it, but it seems like a super versatile board so far.

[Smokey]

True.  Good point.
https://www.ettus.com/product/details/UB200-KIT

[LukeW]

The ADI RF portfolio is only going to get more interesting and higher frequency with the Hittite acquisition.

[Scrts]

Did you check Lime Microsystems?

They have two products on their portfolio:
The LMS6002D can be digitally configured to operate on any mobile communications frequency bands (300MHz to 3.8GHz) and be used any 2G, 3G or 4G mobile communications standard. Additionally, users can easily configure the device to run in 16 bandwidths up to 28MHz.
Price on Digikey: 110USD per single chip

The LMS7002M has a continuous operation spectrum of 0.05 to 3.8GHz, and is software configured to operate up to 50MHz IF bandwidth.
This one is not yet on the Digikey.

AD9361 price: 232.18USD
AD9364 price: 172.48USD

I think they use LMS6002D on bladeRF.

[tonyarkles]

The HackRF One board is also a pretty cool example: https://github.com/mossmann/hackrf/wiki/Hardware-Components

Instead of using a super wideband receiver, it takes a narrower (2.3-2.7GHz) SDR chip and a super wideband synthesizer/mixer to translate a huge band into the SDR chip's bandwidth.

[Smokey]

So I have a little off topic question here...

Why are people using USB2 for a data interface for things when it ends up being the bandwidth limiter?
It seems like Ethernet is the logical choice especially since just about everyone has gigabit Ethernet ports on their computers these days and has for a while now.

I get that USB2 is SUPER easy to add to a project, but is it really that much harder to implement Ethernet?
I guess USB3 would be the choice for new designs, but then again I haven't used USB3 yet.  Anyone with some experience chime in on how hard it is to implement a really high speed USB3 link?

[tonyarkles]

Smokey, I can't really comment much about the implementation difficulties, but I can say that the Ettus B200 above does use USB3 (and I've pushed it hard enough to successfully use the extra bandwidth). They also have a number of different models that use GigE, just like you mentioned.

One disadvantage I can imagine when using GigE is that you're losing some determinism and introducing some latency through the packetization process. With USB3 Isochronous, they're looking at 128MB/s with 200ns accuracy, so that's quite nice[0]. It seems like a less flexible but great performance-wise approach would be to use PCIe.

• http://www.usb.org/developers/presentations/SuperSpeed_USB_DevCon_Isochronous_Froelich.pdf

[Smokey]

The B200 sounds pretty cool.  What are you using it for so far?

I wonder if one of the industrial protocols like ethercat would be a better model for deterministic applications.  I know the new TI Sitara DSPs with the ARM cores can talk full ethercat, and the master (PC) can use off the shelf ethernet hardware.  I would be TOTALLY willing to get a dedicated PCIe network card to use for super high bandwidth SDR connection.

http://www.rtcmagazine.com/articles/view/100822

[Scrts]

And where do you need so much bandwidth?

[tonyarkles]

I wish I could say that I've used it for something cool .

It just showed up a few weeks ago. I've fired it up to test it and successfully built an FM radio receiver in gnuradio, but haven't taken it much further yet. Pretty much the only signal that has flowed through it so far is MC Hammer (yay broadcast FM!)

The bigger picture is that I'm getting into RF design, specifically doing low-cost ISM and BLE sensor design. I'm planning on using the B200 as part of the prototype and debugging process. In order to have a really deep understanding of how the radios and protocols work, I'm going to do one half in hardware and one half in software before doing full two-way hardware-hardware communication.

I'm also a Ham, so pairing it with a Ham It Up, I'll have a pretty compact rig that can Rx almost anything, and Tx low power. I'd love to experiment with the different digital modes and satellite comms, but who knows. More ideas than time available right now.

[tonyarkles]

Oh yeah, http://gnss-sdr.org/ I ran that too with the B200 and it worked awesome. I tried it with an old RTL-SDR I had kicking around (with a bias tee and active antenna), but it was spotty at best. With the B200, it found satellites almost instantly and had nav data streaming shortly after.

[tonyarkles]

And where do you need so much bandwidth?

I don't personally. The B200 purchase for me was based on a few things: full duplex (rules out the HackRF), ability to work on the 2M band (rules out the BladeRF).

One place where the bandwidth is nice is for "scanning". With the low sample rate of the RTLSDR, you can only tune about 2MHz of spectrum. With the wider bandwidth, you can see a whole lot more when you're exploring. I've pretty much only run it full out to verify that my whole system (PC+radio) is capable of using all of the bandwidth available. As an example, I've got enough bandwidth to see the entire 2M band, which I couldn't do with the RTLSDR (admittedly, $20 vs $900, it wouldn't be worth it just for that)

One other example of where the extra bandwidth would come in handy would be OpenBTS http://www.openbts.org/. I personally have no intention of running my own cell network, but it's pretty cool that it's possible to do it!

[Smokey]

As far as high bandwidth, it just seems a shame to have an ADC that can crank out the samples, but having a data link that can't support it.
I'm not working on anything this cool now, but I always through it would be cool to make a phased array with multiple synchronized SDRs, and if they are sharing the USB bus there is no way you could get the data out.

[tonyarkles]

The B200's big brother (B210) can apparently do 2x2 MIMO over USB3 . Not quite a phased array, but not too far off either.