fsk demodulator

[tucoi98]

Hi all,

 I am starting to work on Labview and I have serious doubts about how to approach what I am going to do. I hope you can help me.

I know that it is really difficult to start programming in a completely different environment but I want to go learning little by little every day. For this reason I have just registered in this forum.

First of all I have read a book about Labview and I have also watched some videos on the official website to understand how this whole environment works. Once said that, I need to build a FSK receiver to be able to demodulate and get a message. I've already seen some examples included in the add-on MT (Modulation Toolkit) but I don't know how I should start. Should I take advantage of VI's that already exist or I should program my own VI's? ... Any manual about that, links, examples, whatehever is welcome

PS: I know my question is very general and should probably be more specific but the only thing that I want is to have something that guides me now that I'm new

Thanks in advance to all

[ThiCop]

Hello sambeiro,

Especially if you're a new user, then I would advise you to first start with existing examples.

Another good first step (if you want to start from scratch) would be to first define how your User Interface should look like and also specify the requirements of the application.

Probably you also have these specifications in mind, so writing them down wouldn't cost so much time.

One first important question:

Are you using real hardware to the measurements?

If yes, which type of hardware?

If not, are you starting from a certain measured file?

Another question:

Which book about LabVIEW have you already read?

Based on the "level" of this book I could provide you with other more or less complex Design Patterns to start from/work with.

[tucoi98]

Hello Thicop,

First of all thank you for your answer. I already did some examples and exercises that I found in Internet. I'm going to think about the visual interface and the requirements of the system before to start as you told me.

Yes, I use real hardware to do it. I installed this driver http://joule.ni.com/nidu/cds/view/p/id/2949/lang/en.

I read two manuals that a friend recommended me. I think that both come with the installation CD or something like that.

I'm going to work on it. I will posted as soon as I get something new.

Thank you again

[tucoi98]

Hi again,

I've been thinking in the requirements of my application. The only thing that I know beforehand is the modulation, FSK.

Objective: Demodulate the signal and obtain a sequence of bits knowing the packet time

Unfortunately I don't know anything about the tx filter parameters and the packet format. Neither I know the packet time (I can find this data doing some tests).

Once I have the sequence of bits I will have to be able to determine if there are guard bits, sync bits so that I should prepare somehow this part too.

Do you think that I would need to know something else that the modulation and the packet time?

Here it goes:

[ThiCop]

Hello Sambeiro;

So at the moment we have the following requirements:

- Using the USRP driver to acquire data from a USRP.

- Demodulate (FSK) the data.

Things that are still open:

- Are you acquiring continuously or for a finite amount of time?

- Do you need to log the "results", show them in the User Interface or do both?

- Which kind of platform are you using to run the application on? (eg. Windows PC)

- How much data do you expect to come and at which rate? (which frequencies are you working  at and which frequencies are you modulating with)

- Which type of USRP are you using? (http://www.ni.com/usrp/compare/)

Can it be that something was missing in the original post?

I don't see anything mentioned after "Here it goes:"...

[tucoi98]

Hello ThiCop,

- Are you acquiring continuously or for a finite amount of time? I want to acquire continuously until I press the stop button

- Do you need to log the "results", show them in the User Interface or do both? I have to show the results in the User interface although it would be nice to save the data in logs (this issue is not a priority)

- Which kind of platform are you using to run the application on? Windows 7 PC

- How much data do you expect to come and at which rate? (which frequencies are you working  at and which frequencies are you modulating with). I don't know neither the rate or the modulating frecuency yet. Regarding the frecuency I work in the ISM band.

- Which type of USRP are you using? (http://www.ni.com/usrp/compare/)

NI USRP/2920

I have already started the program. Above I upload a screenshot.

Still there are parts remaining

Thank you very much

[tucoi98]

Hello ThiCop,

- Are you acquiring continuously or for a finite amount of time? I want to acquire continuously until I press the stop button

- Do you need to log the "results", show them in the User Interface or do both? I have to show the results in the User interface although it would be nice to save the data in logs (this issue is not a priority)

- Which kind of platform are you using to run the application on? Windows 7 PC

- How much data do you expect to come and at which rate? (which frequencies are you working  at and which frequencies are you modulating with). I don't know neither the rate or the modulating frecuency yet. Regarding the frecuency I work in the ISM band.

- Which type of USRP are you using? (http://www.ni.com/usrp/compare/)

NI USRP/2920

I have already started the program. Above I upload a screenshot.

Still there are parts remaining

Edit: I can't upload the images... I saved them as JPEG.. How I have to do that?

Thank you very much

[ThiCop]

Hello Sambeiro,

I don't see any screenshot in my browser.

Can you upload the screenshot and the VI's in a zip-folder as an attachment?

[tucoi98]

Hello ThiCop,

I've been working and I have a first version of my program (I have followed an example). You will see that there are parts that are incomplete because I have errors or I don't know how to implement it.

Firstly I have to take a look how to acquire the data from an antenna. Secondly I have errors about the type of data (source data is different than sink data) in the FSK Demodulator VI (within the 'Bit producer loop').

Please take a look my first version and tell me if something else remains.

Thank you very much

Edit: I can't upload the zip, I don't know why. I just press browse and select the folder. Then I press post and nothing happens...

[ThiCop]

Hello Sambeiro,

How big is the file?

Have you tried using a rar-file?

Which browser are you using?