Could I sweep across multiple modulation schemes (FM, AM), while changing the frequency at which I want to transmit at?

[GuilleTech17]

The idea is to build a multi-platform warning system that will be able to transmit a warning message to different devices. It includes FM radio, AM radio and even a UHF radio using multiple modulation schemes. for example (FM, AM ). The idea I have in mind is to sweep across of different frequencies while changing it modulations. I'm a newbie, so this is my first time using software define radio.

1. Could I be able to change modulation while transmitting?(for this project i will be using USRP-2920 unit

2. lastly is there any examples or places that I could information related to this topic?

Any resources or feedback would be very appreciated.

Thank you very much.

[Alex.W]

Hello GuilleTech17,

Would you need to be transmitting continuously? Or could you transmit with one modulation scheme for a set frequency range, stop and reset your modulation scheme and then transmit over the new frequency range? Is there a specific reason for your application that you would need to change the modulation scheme in the middle of a transmission?

Are you using NI Modulation Toolkit? If so, then you will have access to examples for FM and AM modulation schemes. Otherwise, there are some examples in our community examples that may be applicable.

In terms of frequency sweeping, I will point you towards this other forum as a starting point: How to switch central frequency fastly with labview and USRP?

I wish you the best of luck on your project!

[cr7ronaldo17]

Hello Best.West, thanks for the reply.

I will explain myself better. The main idea of my project is to create a warning broadcast system that will interfere FM and AM stations when there is an emergency. A message warning so anyone who is listening to the radio, could hear it.

1. I would like to transmit a warning message over a range of
frequencies then automatically change of modulation, if possible.

2. like I mentioned before, I just started to use the NI-2920 unit. I have downloaded the modulation toolkit, NI-USRP drivers, and Labview.

Lastly, I have this question. Do you know whether is possible to send text messages to a cellphone using a USRP? could this be possible? I read somewhere you can transfer packets using UDP protocol.

Thanks for the feedback, I appreciate.

[Alex.W]

Hello cr7ronaldo17,

Interesting application!

You can automate the frequency scanning and switch the modulation schemes through the LabVIEW environment but there are no examples that we have prebuilt with this functionality.

As a result, the best strategy will be to piece together different examples to meet your needs. A great place to start to get familiar with the LabVIEW environment and different programming architectures that you can use is by going through the LabVIEW Core 1 and LabVIEW Core 2 training.

Also taking advantage of the National Instruments community, there are a lot of examples that customers have put together and posted online.

For instance, a search for "Send a Test Message from LabVIEW" pulled up a series of documentation. I have linked three below:

Can LabVIEW Send Text Messages to a Cell Phone?

Sending SMS (text messages) using SMTP with LabVIEW

Send Text Message Using SMTP API

For examples related to frequency sweeping:

NI Example: niUSRP EX Tx Continuous Async Reconfig on the Fly.vi

Two related to our niFgen Driver but showing the functionality you want:

LabVIEW Frequency Sweep Example for the NI PXI-5404

AWG Frequency Sweep Example

This forum talks about the application for a USRP:

How to switch central frequency fastly with labview and USRP?

For examples related to modulation schemes:

niUSRP EX FM Demod Sound Card (Queue).vi

niUSRP EX FM Demod Sound Card (Shift Reg).vi

niUSRP EX PAM Tx.vi

niUSRP EX QAM Tx.vi

There are a lot of different implementations that you can use to create a program with the functionality you are trying to achieve. These are some great getting started material, but the implementation you will need to select a strategy you are comfortable with.

I wish you the best of luck!

Regards,