Re: [Discuss-gnuradio] Detailed Analysis

[Paul B. Huter]

Aditya:

Say, for example, that at nine seconds there is a spike at around 15MHz. I want to see if that spike stays there until the end of my data file (at about 13 seconds). I am trying to determine if the signal at 15MHz sticks around for awhile. I am setting a "hold" on my FFT at nine seconds, which shows up in red, then the FFT keeps going, showing up in blue. I can try to "analyze" it by looking at it, but it seems rather inaccurate. I am trying to find a better way to do this type of analysis, which may be possible with the Waterfall, but I think I may need another tool.

On Wed, Jan 22, 2014 at 6:43 PM, Aditya Dhananjay <address@hidden> wrote:

On Wed, Jan 22, 2014 at 7:26 PM, Paul B. Huter <address@hidden> wrote:

Aditya:

I am looking at sections of my data, one-M at a time - that is, from 0 MHz to 1 MHz, 1 MHz to 2 MHz, etc. So, for example, when I look at 0-to-1 MHz, I am using an FFT set to FFT-size of 1000. My data is about 13 seconds long, and I am looking at it at a rate of 1 Hz (so I see about 13 updates). What I am trying to see is if the data at about nine seconds persists to the end of the data at 13 seconds. I have tried holding the data at nine seconds and seeing if things keep matching up, but that is really not working out for me. I have yet to look at it from a Waterfall perspective, which may yield better results. However, in experimenting with the Waterfall, I am unable to get the "window" to be set the way I can set it with the FFT plot. I am getting ready to grab another data set tomorrow, but I would like to do some analysis prior to getting another data file.

Hi Paul,

I'm not sure I understand what you're trying to get to work. Let's say you want to examine the signal over N buckets of bandwidth 1MHz each. Can you stream your data into a bank of N band-pass filters in parallel, and then examine the FFT output through N FFT plots?

(Sorry, but I don't think I'm being of much help here.)

Best,

Aditya