# A Couple Questions

**URL:** <https://www.ruby-forum.com/t/a-couple-questions/238206>\
**Category:** GNU Radio\
**Created:** [December 23, 2013, 10:11pm UTC](https://www.ruby-forum.com/t/a-couple-questions/238206 "2013-12-23T22:11:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [December 23, 2013, 10:11pm UTC](https://www.ruby-forum.com/t/a-couple-questions/238206/1 "2013-12-23T22:11:23Z")

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I have a data file that was recorded to a RAMDisk and transferred to the  
hard drive on my Linux machine. When I run it through a throttle, a  
filter,  
and into an FFT, the file repeats. When I was running it off the  
RAMDisk,  
it only played for the ~15 seconds of the data. I was having the problem  
with repeating before I rebooted and lost the RAMDisk file (I thought  
maybe  
having it stored in RAM, too, was causing a problem). Also, the buttons  
on  
the FFT plot don’t work (Autoscale, Stop) Can anyone provide any insight  
into why the file on my hard drive is repeating? “Repeat” is set to “No”  
on  
the file source block.

Second question - On the FFT (same flow) how can I make it so it STARTS  
viewing all the data? The FFT shows up going from 0 to 100, and the  
majority of the data is negative. As mentioned, it only runs for about  
15  
seconds, and even if the Autoscale button worked, I have such a small  
window to view everything. It is my understanding that I can’t get an  
Autoscale prior to viewing the plot, but is there a way to scale it with  
the parameters on the flow block (maybe set it to go from 0 to -100)?

Thanks!

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**Author:** ![Paul\_BSHuter](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e8c25b/32.png) [@Paul\_BSHuter](https://www.ruby-forum.com/u/Paul_BSHuter)\
**Post date:** [December 24, 2013, 12:10am UTC](https://www.ruby-forum.com/t/a-couple-questions/238206/2 "2013-12-24T00:10:33Z")

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Hello,

If the buttons aren’t working then the thing is probably locked up, try  
lowering the fft\_rate parameter and see if that fixes things.

Andrew

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**Author:** ![Paul\_BSHuter](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e8c25b/32.png) [@Paul\_BSHuter](https://www.ruby-forum.com/u/Paul_BSHuter)\
**Post date:** [December 24, 2013, 12:53am UTC](https://www.ruby-forum.com/t/a-couple-questions/238206/3 "2013-12-24T00:53:46Z")

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Thanks, Andrew, I will give that a try. But I am curious as to why it  
worked fine when running it off of the RAMDisk, but I have problems  
running  
the exact same file off of the hard drive. Am I having an issue with the  
read-speed on the hard drive (just as I was having an issue with the  
write-speed, which led to me using the RAMDisk)?