[Hackrf-dev] NBFM problems

[k6eep at hamsoftware.org]

Oh drat I forgot about that DC spike.  I had gone through all the tutorials.  I guess I have a bad case of information overload.  Thank you for reminding me.
Mike

> On Jul 1, 2016, at 8:37 AM, Cinaed Simson <cinaed.simson at gmail.com> wrote:
> 
> Here's a simple NBFM receiver.
> 
> Note, center_freg contains a DC spike - you need to look at the signal
> of interest off center.
> 
> See the Michael Ossmann tutorials at
> 
>  https://greatscottgadgets.com/sdr/
> 
> The first lesson takes the enclosed flow graph and builds a tuneable FM
> receiver by adding a signal source, channel_freq, low pass filter,
> rational resampler, FM modulator and audio sink
> 
>  https://greatscottgadgets.com/sdr/1/
> 
> Also, lesson 5 is the HackRF One operating manual
> 
>  https://greatscottgadgets.com/sdr/5
> 
> On 06/30/2016 08:49 PM, k6eep at hamsoftware.org wrote:
>> I am having trouble getting clear sounding audio out of my HackRF One receiver in NBFM mode.
>> The audio sounds raspy.  
>> I am using an external 10Mhz GPS disciplined TCXO clock.
>> I ran all the gains down and up but the raspy sounding audio persists.
>> RF=0, IF=16, BB=16 as default gains.
>> Here is a link to my grc setup.
>> http://hamsoftware.org/SDR/NBFM_quad.grc.png
>> 
>> I am got WBFM working pretty well.  Even have RDS on it.  
>> I am running this on Ubuntu 16.04.  I used the Ubuntu binaries for GnuRadio.
>> I am sure I am making some sort of mistake.
>> Oh, I also tried this on both a USB-2 and USB-3 port. No difference.
>> 
>> I am new to SDR.  Trying to find a good source for grc examples also.
>> Heck of a learning curve. 
>> Mike
>> _______________________________________________
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>> HackRF-dev at greatscottgadgets.com
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>> 
> 
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