Re: [Discuss-gnuradio] Doppler shift on waterfall plot with audio signal

[Chris Kuethe]

It sounds like something specific to your machine because my laptop
runs that flowgraph without issue. Some more guesses:

Make a simple flowgraph to play a 1kHz tone through the speaker. Can
you hear the tone?
Make a simple flowgraph to feed the microphone into an FFT and a
waterfall. Do you see anything in response to ambient sound (music,
talking)?
Double check your sound card's mixer and gain settings if these don't work.
Try both flowgraphs at the same time. I'd be surprised, but maybe your
hardware can't do full-duplex? Maybe you need to pick a different ALSA
device string. Maybe there's some fancy echo-cancellation getting in
the way.

When it's working, you'll totally be able to detect hand-waving around
your computer.


On Fri, Oct 21, 2016 at 2:16 PM, Steve Gough <address@hidden> wrote:
> Thanks for getting back.
>
> There seems to be an issue with WX Waterfall SInk. The WX waterfall sink
> gives all blue as before, while the QT GUI Waterfall Sink gives a figure
> like attached. (attachment1.png) .
>
> I also don't see a sharp peak at 0 like your attachment. Could this be a
> hardware issue ?
>
> Nothing is muted.
>
>
>
>
> On Fri, Oct 21, 2016 at 4:28 PM, Chris Kuethe <address@hidden>
> wrote:
>>
>> I've been meaning to do some more experimentation here using CW, FMCW,
>> and chirps.
>>
>> You should be seeing a bright line down the middle of the waterfall.
>> If not, your hardware isn't working - I'm thinking it's your speakers
>> since you do seem to be gettting *something* from the microphone on
>> your FFT. You won't hear the tones since they're ultrasonic, but is
>> your sound muted?
>>
>> On Fri, Oct 21, 2016 at 10:01 AM, Steve Gough <address@hidden>
>> wrote:
>> > Hi All,
>> >
>> > I am interested in analyzing the doppler shift of a transmitted signal.
>> >
>> > As a first step, I want to see if I can capture hand movements in a
>> > Waterfall sink for an audio signal (tone). For that I use a flow graph
>> > like
>> > the attached screenshot based on
>> > https://github.com/ckuethe/gnuradio-examples/tree/master/doppler_sonar
>> > and
>> > https://www.youtube.com/watch?v=9trGfdcMPtk&noredirect=1.
>> >
>> > I don't observe any doppler shift when I move my hand/walk in the
>> > vicinity.
>> > I can see the FFT plots change in shape on motion, but nothing is
>> > observed
>> > on the Waterfall sink.
>> >
>> > Could you please tell me if I am missing something here?
>> >
>> > The observed waterfall spectrogram is also attached.
>> >
>> > Thanks,
>> > Steve
>> >
>> > _______________________________________________
>> > Discuss-gnuradio mailing list
>> > address@hidden
>> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>> >
>>
>>
>>
>> --
>> GDB has a 'break' feature; why doesn't it have 'fix' too?
>
>



-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?