# Overflow error even at lower sampling rates

**URL:** <https://www.ruby-forum.com/t/overflow-error-even-at-lower-sampling-rates/227539>\
**Category:** GNU Radio\
**Created:** [March 19, 2013, 5:31am UTC](https://www.ruby-forum.com/t/overflow-error-even-at-lower-sampling-rates/227539 "2013-03-19T05:31:47Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![john\_old](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9f8e36/32.png) [@john\_old](https://www.ruby-forum.com/u/john_old)\
**Post date:** [March 19, 2013, 5:31am UTC](https://www.ruby-forum.com/t/overflow-error-even-at-lower-sampling-rates/227539/1 "2013-03-19T05:31:47Z")

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Hi,

I am getting overflow error ,even at low sampling rates.I am using USRP  
N210 device.If the sampling rate is less than 5MHz then there is no  
error.I  
know that USRP N210 can support at Max 25MHz.Can you please tell me what  
might be the problem?

I just connected UHD source block to FFT sink in my example.

My system specifications.

OS :Ubuntu 12.10  
processor :Intel Core i5-3570 CPU @ 3.40GHz 4  
RAM 4GB

I am using 1Gbit Ethernet card.

Thanks

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**Author:** ![john\_old](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9f8e36/32.png) [@john\_old](https://www.ruby-forum.com/u/john_old)\
**Post date:** [March 20, 2013, 4:12am UTC](https://www.ruby-forum.com/t/overflow-error-even-at-lower-sampling-rates/227539/2 "2013-03-20T04:12:08Z")

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> OS :Ubuntu 12.10  
> processor :Intel Core i5-3570 CPU @ 3.40GHz 4  
> RAM 4GB
> 
> I am using 1Gbit Ethernet card.
> 
> Thanks  
> Overruns are caused by your computer not being able to “keep up” in real  
> time with the dataflow from the USRP.

What happens if you use “uhd\_fft” at the sames rates you’re getting  
overflow with in your simple flow-graph?

–  
Marcus L.  
Principal Investigator  
Shirleys Bay Radio Astronomy Consortium

> **[Live Draw HK Tercepat | Result HK | HK Pools | Live HK | HK Prize Hari Ini](https://www.sbrac.org)**
>
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<div class="post-metadata">

**Author:** ![john\_old](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9f8e36/32.png) [@john\_old](https://www.ruby-forum.com/u/john_old)\
**Post date:** [March 21, 2013, 7:07am UTC](https://www.ruby-forum.com/t/overflow-error-even-at-lower-sampling-rates/227539/3 "2013-03-21T07:07:14Z")

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Hi Marcus,  
I am not getting overflow,when i use uhd\_fft. Can you please tell me  
what  
might be the problem.

Thanks.

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<div class="post-metadata">

**Author:** ![john\_old](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9f8e36/32.png) [@john\_old](https://www.ruby-forum.com/u/john_old)\
**Post date:** [March 21, 2013, 2:22pm UTC](https://www.ruby-forum.com/t/overflow-error-even-at-lower-sampling-rates/227539/4 "2013-03-21T14:22:33Z")

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On Thu, Mar 21, 2013 at 2:06 AM, john jade [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Hi Marcus,  
> I am not getting overflow,when i use uhd\_fft. Can you please tell me what  
> might be the problem.
> 
> Thanks.

All uhd\_fft does is connect a USRP source to an FFT sink. Problems  
arise when you add more blocks to your application that take more  
processing time. The more CPU intensive the task, the harder it is to  
keep up with the flow of data.

Tom