|
From: | abhinav narain |
Subject: | Re: [Discuss-gnuradio] question about using FSK on noise |
Date: | Tue, 7 Jun 2016 11:09:52 -0400 |
ChrischeersAre you using RF or ultrasound out of interest, to grab emissions from the SMPS?Hi Abhinav,This sounds really interesting!On Tue, Jun 7, 2016 at 6:35 AM, abhinav narain <address@hidden> wrote:_______________________________________________Hi all,I am trying to make a covert communication channel using SMPS noise generated by the processor as a part of my research.I see a change in frequency emitted by the processor when I run the following loop (http://pastebin.com/uRghLuLm) with message variable containing the message, and see the spectrogram (http://postimg.org/image/g0ec0nvqj/full/), with fluctuating red points ~60kHz, indicating the change due to a loop and sleep executed on the processor.I want to decode the bits and I think I should use FSK, although I lack understanding to configure the details.The following is the current flowgraph where I have used bandpass filter to narrow down the signal to ~60kHz and using quadrature block to demodulate.Since the entity of interest is actual SMPS noise of the laptop adapter instead of a sinosoid, I have no clue how to write a clear decoder after looking at some tutorials of GNU Radio to know the symbol rate etc for the clock recovery algorithm.I would be grateful, if someone can guide me on how to proceedThanks,Abhinav
Discuss-gnuradio mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Prev in Thread] | Current Thread | [Next in Thread] |