I have a raw grabbed data from spectrometer that was working on wifi (802.11b) channel 6.
(two laptops in ad-hoc ping each other).
I would like to decode this data in matlab.
I see them as complex vector with 4.6 mln of complex samples.
I see their spectrum quite nice. I am looking document a bit less complicated as IEEE 802.11 standard (which I have).
I can share measurement data to other people.
There's now a few solutions around for decoding 802.11 using Software Defined Radio (SDR) techniques. As mentioned in a previous answer there is software that is based on gnuradio - specifically there's gr-ieee802-11 and also 802.11n+. Plus the higher end SDR boards like WARP utilise FPGA based implementations of 802.11. There's also a bunch of implementations of 802.11 for Matlab available e.g. 802.11a.
If your data is really raw then you basically have to build every piece of the signal processing chain in software, which is possible but not really straightforward. Have you checked the relevant wikipedia page? You might use gnuradio instead of starting from scratch.
I have used 802.11 IEEE standard to code and decode data on matlab.
Coding data is an easy task.
Decoding is a bit more sophisticated.
I agree with Stan, it is going to be tough doing everything yourself. you may get some ideas from the projects on CGRAN like :
https://www.cgran.org/wiki/WifiLocalization
Related
I feel I have put it a decent effort in searching for a solution to my problem online, but can't find what I need in order to accomplish my goal.
Essentially, what I need to do is parse data from a file being received by my FPGA through serial. The data is fairly extensive and I think it would be easier if were able to use some of the functions inside of the textIO library.
All of the techniques I have found online reffering to data parsing is only for simulation. I need this to actually happen on the FPGA.
So my question is, is there a way to create a file internally on the FPGA and have the input from serial write to it then be able to use the textIO functions on that txt file?
Some psuedo code might look somthing like:
File_Open("newFile.txt", write) --If it doesn't exist, then create it
write(SerialByteStream, newFile.txt) --Collect serial data onto txt file
Then run textIO function on newFile.txt in order to use the data in newFile.txt
Also, it's worth mentioning that I am new to FPGA's and VHDL, so it could be that there is a trivial solution that I am not aware of. And I'm using VHDL with the Altera DE2-115.
I appreciate any help.
No, what you are proposing is not possible. As you have found, VHDL's file i/o are really just instructions to the simulator to do something. Note the distinctions between synthesisable and non-synthesisable VHDL. You can only program the synthesisable part of your VHDL into an FPGA, and this usually won't include file related libraries.
Complex file operations are a general purpose processing task - what PCs do. Your best avenue of investigation is probably to reconsider what you want the FPGA for in the first place and focus on that.
Some possibilities:
If the FPGA is only to provide an interface to read and write some byte stream onto a PC, perhaps you should do precisely that. Do the data processing on the PC. Transferring the data is still not trivial, but in this case you needed to solve that problem anyway.
If you need the FPGA for some high performance computations, see if you can pre-process and provide that data in a format that is easier for your design to digest.
If really necessary, processing your serial byte stream with VHDL may not be as hard as it sounds, especially if you only need to operate on it linearly. Probably you need a design involving at least one state machine that parses your serial byte stream, but the rest all depends on the details of your problem.
If you really need complex processing ON the FPGA, consider using a soft core CPU. There may be open source ones that fit on your FPGA. Whatever you want to do may be easier to write in C, which you can then compile and run on the FPGA. That option gives you a very flexible standalone hardware component, but if you need very high performance or it you do not have much time to set it up, this is probably not right for you.
I would like to reproduce the experiment from Dr. Adrian Thompson, who used genetic algorithm to produce a chip (FPGA) which can distinguish between two different sound signals in a extreme efficient way. For more information please visit this link:
http://archive.bcs.org/bulletin/jan98/leading.htm
After some research I found this FPGA board:
http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=167&No=836&PartNo=1
Is this board capable of reproducing Dr. Adrian Thompsons experiment or am I in need of another?
Thank you for your support.
In terms of programmable logic, the DE1-SoC is about ~20x bigger, and has ~70x as much embedded memory. Practically any modern FPGA is bigger than the "Xilinx XC6216" cited by his papers, as was linked to you in the other instance of this question you asked.
That said, most modern FPGAs don't allow for the same fine-granularity of configuration, as compared to older FPGAs - the internal routing and block structures are more complex, and FPGA vendors want to protect their products and compel you to use their CAD tools.
In short, yes, the DE1-SoC will be able to contain any design from 12+ years ago. As for replicating the specific functions, you should do some more research to determine if the methods used are still feasible with modern chips and CAD tools.
Edit:
user1155120 elaborated on the features of the XC6216 (see link below) that were of value to Thompson.
Fast Configuration: A larger device will generally take longer to configure, as you have to send more configuration data. That said, I/O interfaces are faster than they were 15 years ago, so it depends on your definition of "fast".
Reconfiguration: Cyclone V chips (like the one in the DE1-SoC) do support partial reconfiguration, but the subscription version of the Quartus II software is required, in addition to a separate license to support PR. I don't believe it supports wildcard reconfiguration, though I could be mistaken.
Memory-Mapped Addressing: The DE1-SoC's internal data can be access through the USB Blaster interface. However, this requires using the SystemConsole on the host PC, so it's not a direct access.
I'm interested in starting a hobbyist project, where I do some image processing by interfacing HW and SW. I am quite a newbie to this. I know how to do some basic image processing in Matlab using the existing image processing commands.
I personally enjoy working with HW and wanted to a combination of HW/SW to be able to do this. I've read articles on people using FPGAs and just basic FPGAs/micro-controllers to go about doing this.
Here is my question: can someone recommend languages I should consider that will help me with interfacing on a PC? I image, the SW part would essentially be a GUI and is place-holder for all the processing that is done on the HW. Also in-terms of selecting the HW and realistically considering what I could do on the HW, could I get a few recommendations on that too?
Any recommendations will be appreciated!
EDIT: I read a few of the other posts saying requirements are directly related to knowing what kind of image processing one is doing. Well initially, I want to do finger print recognition. So filtering and locating unique markers in the image etc.
It all depends on what you are familiar with, how you plan on doing the interface between FPGA and PC, and generally the scale of what you want to do. Examples could be:
A fast system could for instance consist of a Xilinx SP605
board, using the PCI Express interface to quickly transfer image
data between PC and FPGA. For this, you'd need to write a device
driver (in C), and a user-space application (I've done this in
C++/Qt).
A more realistic hobbyist system could be a Xilinx SP601
board, using Ethernet to transfer data - you'd then just have to
write a simple protocol (possibly using raw sockets (no TCP/UDP) to
make the FPGA side Ethernet simpler), which can be done in basically
any language offering network access (there's a Xilinx reference
design for the SP605 demonstrating this).
The simplest and cheapest solution would be an FPGA board with a
serial connection - you probably wouldn't be able to do any
"serious" image processing with this, but it should be enough for
very simple proof-of-concept stuff, although the smaller FPGA devices used o these boards typically do not have much on-board memory available.
But again, it all depends on what you actually want to do.
For programming FPGAS, is it possible to write my own place & route routines? [The point is not that mine would be better; the point is whether I have the freedom to do so] -- or does the place & route stage output into undocumented bitfiles, essengially forcing me to use proprietary tools?
Thanks!
There's been some discussion of this on comp.arch.fpga in the past. The conclusion is generally that unless you want to attract intense legal action from the FPGA companies then you probably don't want to do something like this. bitfile formats are closely guarded secrets of the FPGA companies and you would likely have to understand the file format in order to do what you want to do. That implies that you would need to reverse engineer the format and that (if you made your tool public in any way) would get you a lawsuit in short order.
I will add that there probably are intermediate files and that you likely wouldn't read or write the bitfile itself to do what you want to do, but those intermediate files tend to be undocumented as well. Read the EULA for your FPGA synthesis tool (ISE from Xilinx, for example) - any kind of reverse engineering is strictly forbidden. It seems that the only way we'll ever have open source alternatives in this space is for an open source FPGA architecture to emerge.
I agree with annccodeal, but to amplify a little bit, on Xilinx, there may be a few ways to do this. The XDL file format allows (or used to allow) explicit placement and routing. In addition, it should be possible to script the FPGA Editor to implement custom routing.
As regards placement, there is a rich infrastructure to constrain technology mapping of logic to primitives and to control placement of those primitives. For example LUT_MAP constraints can control technology mapping and LOC and RLOC constraints can determine placement. In practice, these allow the experienced designer great control over how a design is implemented without requiring them to duplicate man-centuries of software development to generate a bitstream directly.
You may also find interesting the current state of the art FPGA CAD research software such VPR. In my opinion these are challenged to keep up with vendor's own tools that must cope with modern heterogeneous FPGAs with splittable 6-LUTs, DSP blocks, etc.
Happy hacking.
Is it possible to write a program that can extract a melody/beat/rhythm provided by a specific instument in a wave (or other music format) file made up of multiple instruments?
Which algorithms could be used for this and what programming language would be best suited to it?
This is a fascinating area. The basic mathematical tool here is the Fourier Transform. To get an idea of how it works, and how challenging it can be, take a look at the analysis of the opening chord to A Hard Day's Night.
An instrument produces a sound signature, just the same way our voices do. There are algorithms out there that can pick a single voice out of a crowd and identify that voice from its signature in a database which is used in forensics. In the exact same way, the sound signature of a single instrument can be picked out of a soundscape (such as your mixed wave) and be used to pick out a beat, or make a copy of that instrument on its own track.
Obviously if you're thinking about making copies of tracks, i.e. to break down the mixed wave into a single track per instrument you're going to be looking at a lot of work. My understanding is that because of the frequency overlaps of instruments, this isn't going to be straightforward by any means... not impossible though as you've already been told.
There's quite an interesting blog post by Comparisonics about sound matching technologies which might be useful as a start for your quest for information: http://www.comparisonics.com/SearchingForSounds.html
To extract the beat or rhythm, you might not need perfect isolation of the instrument you're targeting. A general solution may be hard, but if you're trying to solve it for a particular piece, it may be possible. Try implementing a band-pass filter and see if you can tune it to selects th instrument you're after.
Also, I just found this Mac product called PhotoSounder. They have a blog showing different ways it can be used, including isolating an individual instrument (with manual intervention).
Look into Karaoke machine algorithms. If they can remove voice from a song, I'm sure the same principles can be applied to extract a single instrument.
Most instruments make sound within certain frequency ranges.
If you write a tunable bandpass filter - a filter that only lets a certain frequency range through - it'll be about as close as you're likely to get. It will not be anywhere near perfect; you're asking for black magic. The only way to perfectly extract a single instrument from a track is to have an audio sample of the track without that instrument, and do a difference of the two waveforms.
C, C++, Java, C#, Python, Perl should all be able to do all of this with the right libraries. Which one is "best" depends on what you already know.
It's possible in principle, but very difficult - an open area of research, even. You may be interested in the project paper for Dancing Monkeys, a step generation program for StepMania. It does some fairly sophisticated beat detection and music analysis, which is detailed in the paper (linked near the bottom of that page).