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Frequency Counter‏

Dimitris Siafarikas

Hi list,

 

Has anyone been able to implement a frequency counter yet?


Any ideas on how I should try it?


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Re: Frequency Counter‏

madengr
jimsiaf91 wrote
Hi list, Has anyone been able to implement a frequency counter yet?
Any ideas on how I should try it?    
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I have been pulling FFT vectors out of the flow into python using a message queue, then finding the frequency of the maximum bin.  I suppose you could do this, retune the USRP or channelizer, then increase the decimation.  Keep doing this to narrow down the spectrum.

I suppose a gated type counter would work too, where you just could the cycles, and may work better for modulated signals.

Lou
KD4HSO
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Re: Frequency Counter‏

Mike Jameson-2
The 'spectrum sense mode' in scanoo locks on to the strongest signal within the rx bandwidth.  Just set the squelch and then enable spectrum sense in the spectrum sense tab:
Mike

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Mike Jameson M0MIK BSc MIET
Email: [hidden email]
Web: http://scanoo.com


On Mon, May 5, 2014 at 4:41 PM, madengr <[hidden email]> wrote:
jimsiaf91 wrote
> Hi list, Has anyone been able to implement a frequency counter yet?
> Any ideas on how I should try it?
> _______________________________________________
> Discuss-gnuradio mailing list

> Discuss-gnuradio@

> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

I have been pulling FFT vectors out of the flow into python using a message
queue, then finding the frequency of the maximum bin.  I suppose you could
do this, retune the USRP or channelizer, then increase the decimation.  Keep
doing this to narrow down the spectrum.

I suppose a gated type counter would work too, where you just could the
cycles, and may work better for modulated signals.

Lou
KD4HSO



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View this message in context: http://gnuradio.4.n7.nabble.com/Frequency-Counter-tp47952p47957.html
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Re: Frequency Counter‏

Marcus Müller-3
In reply to this post by Dimitris Siafarikas
Hi Dimitris,

a frequency counter counter is a very analog-world concept, I'd say.
As DSP person I'd assume you'd want a frequency estimator.
You can implement a simple one by using an FFT block, abs, max arg
chain, or just get your result from looking at any FFT plot.

Anyway, for spectrum estimation, I recommend the gr-specest toolbox,
https://github.com/kit-cel/gr-specest

Greetings,
Marcus

On Mon, May 5, 2014 at 10:25 AM, Dimitris Siafarikas
<[hidden email]>wrote:

> Hi list,
>
>  
>
> Has anyone been able to implement a frequency counter yet?
>
>
> Any ideas on how I should try it?
>  
> _______________________________________________
> Discuss-gnuradio mailing list
> [hidden email]
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>


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Re: Frequency Counter‏

Marcus Müller-3
Ah sorry, I didn't mean to put it that way: It's not an analog device;
the thing I wanted to point out
that there being a device that counts frequency --to me-- belongs to a
very "analog" thinking (i.e. it's not math on a computer, but an actual
thing with an HF connector). Actually, you're absolutely right, counting
things in discrete steps in defined time intervals is the most digital
thing one could do.

Thanks for your mail!

Greetings,
Marcus

On 05.05.2014 19:29, jmfriedt wrote:

> Not sure I agree with this statement: all frequency counters are, to the
> best of my knowledge, digital components (eg HP53131A for the most
> classical instrument). http://jmfriedt.free.fr/fosdem2014.pdf demonstrates
> on slide 16 a comparison of direct and reciprocal counters used on a 32768 Hz signal
> generated by a tuning fork oscillator and sampled on the sound card.
>
> JM
>
>> a frequency counter counter is a very analog-world concept, I'd say.
>> As DSP person I'd assume you'd want a frequency estimator.
>> You can implement a simple one by using an FFT block, abs, max arg
>> chain, or just get your result from looking at any FFT plot.
>>
>> Anyway, for spectrum estimation, I recommend the gr-specest toolbox,
>> https://github.com/kit-cel/gr-specest
>>
>> Greetings,
>> Marcus
>>
>> On Mon, May 5, 2014 at 10:25 AM, Dimitris Siafarikas
>> <[hidden email]>wrote:
>>
>>> Hi list,
>>>
>>>  
>>>
>>> Has anyone been able to implement a frequency counter yet?
>>>
>>>
>>> Any ideas on how I should try it?
>>>  
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
>>> [hidden email]
>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>
>>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> [hidden email]
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>


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Re: Frequency Counter‏

Dimitris Siafarikas
This post has NOT been accepted by the mailing list yet.
In reply to this post by Mike Jameson-2
Mike,

I tried to run the GRC flow but when I opened the .grcm multiple errors poped

/home/ubuntu/Desktop/scanoo.com_rx.grc:5693:64922:FATAL:PARSER:ERR_UNDECLARED_ENTITY: Entity 'nbsp' not defined

what am I doing wrong?
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Re: Frequency Counter‏

Dimitris Siafarikas
This post has NOT been accepted by the mailing list yet.
In reply to this post by Marcus Müller-3
Marcus,

I have implemented a CW radar and until now I can see the frequency shift on a waterfall plot. But, what I would like to do is to appear a textbox with the approximate speed of the moveing target. That's why I am looking for a way to depict the frequency somehow.

I tried this your chain and it worked like a charm.

The negatives are that it does not work for frequencies bigger thar few kHz (~50kHz) and when I am moving the slider to adjust the source signal, then the Number sink (where I observe the frequency) flickers between the right nymber and some random (I think) number. Any thoughts on that?


Thank you!
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Re: Frequency Counter‏

activecat
In reply to this post by Dimitris Siafarikas

On Mon, May 5, 2014 at 4:25 PM, Dimitris Siafarikas <[hidden email]> wrote:

Hi list,

Has anyone been able to implement a frequency counter yet?

Any ideas on how I should try it?


Hi Dimitris,

Yes. 
I have recently created a block for frequency counting, refer https://github.com/activecat/gr-test2

Try to run this flowgraph:  gr-test2/examples/flowgraph_04.grc
amazingly it shows quite an accurate result.

Let's test it with various frequencies by adjusting the GUI Slider.

I created this block when I need to observe the frequency stability of signal from USRP, as in flowgraph_05.
Hope this block is useful to you too.

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Re: Frequency Counter‏

activecat

On Tue, Jun 3, 2014 at 11:41 PM, Dimitris Siafarikas <[hidden email]> wrote:

Exceptional work! Looking forward to try this with my usrp tomorrow ;)

 



Dimitris,

How is your test result with USRP, any updates ..?



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Re: Frequency Counter‏

Dimitris Siafarikas
This post has NOT been accepted by the mailing list yet.
Well,

I tried it with my usrp N210. The first time it showed something on the Scope sink. After that it did not.

Only when I run first the flowgraph_6.grc then the 5th ( the one with the USRP source) showed something. I do not understand why this is happening.

Besides that, I tried to measure at 2Ghz with and external frequency generator (sin) and also attached a number sink after the block you wrote. The number sink did not show 2Ghz (in units), instead jittered at about 1000 units.

Should I place a PLL block maybe?




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Re: Frequency Counter‏

activecat
First of all, please stay on the list.
Refer inline reply below.


On Fri, Jun 6, 2014 at 11:12 PM, jimsiaf91 [via GnuRadio] <[hidden email]> wrote:
Well,
I tried it with my usrp N210. The first time it showed something on the Scope sink. After that it did not.

Your setup could be wrong.

 
Only when I run first the flowgraph_6.grc then the 5th ( the one with the USRP source) showed something. I do not understand why this is happening.

I see no correlation on this.

 
Besides that, I tried to measure at 2Ghz with and external frequency generator (sin) and also attached a number sink after the block you wrote. The number sink did not show 2Ghz (in units), instead jittered at about 1000 units.

If the Sample Rate (samp_rate) of the UHD (USRP) source is only 100kHz, it cannot measure 2GHz external frequency.
Refer Nyquist sampling theory.
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