[Hackrf-dev] help identifying signal

[Dominic Spill]

On 7 December 2015 at 11:28, xun wang <xun911 at gmail.com> wrote:
> how come baudline doesn’t need to do any those things to see the bits clearly? wish there’re more resources to learn baudline though...

Any tool that plots frequency vs time vs power (baudline, inspectrum,
waterfall plot) allows you to see where any signal is in your received
data.  When building a GNU Radio flowgraph you need to let the blocks
know where the signal is so that they can decode the signal that
you're interested in.

This may not seem like a large distinction for a single recording of a
keyfob with very little background noise, but when you try to pluck
signals out of noisy bands it becomes much harder.  In general, GNU
Radio and the underlying DSP algorithms are designed to process
signals in the centre of the received spectrum.  Someone smarter than
me can probably give you more details on this.

When you view a waterfall plot, the signals are easy to pick out
because your eyes are good at spotting patterns.

Dominic

>> On Dec 6, 2015, at 7:03 PM, xun wang <xun911 at gmail.com> wrote:
>>
>> Hi, I’m very new to SDR and I’m not an engineer, but I do have some experience in programming, and I’m also very interested in learning all about it signal processing. I played around with building an FM in gnuradio, GPS simulation, pager decoding & ADS-B and they’re simple enough & fun with readily built tools available. Now I want to go deeper into SDR.
>>
>> I went through Michael’s video tutorial and is the process of learning more from various sources. Last night I borrow my friend’s Prius key fob and recorded some files to take a look with my HackRF. I can’t seem to identify 1 or 0s because it looks to have more than 2 possibilities to me. I’ve processed the file to the best of my knowledge(which is not deep at all) mainly based on the hint from Michael’s Lesson 8 & 9. Can someone take a look and see what’s the next step I should do to further identify it? or it’s already pretty clear and I just don’t see it due to my inexperience? thank you!
>>
>> Here is a screenshot: http://imgur.com/1CXGcoJ
>>
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