# LimeSDR high sample rate time series dropout

**URL:** <https://discourse.myriadrf.org/t/limesdr-high-sample-rate-time-series-dropout/5776>\
**Category:** LimeSDR\
**Created:** [18 February 2020 09:58 UTC](https://discourse.myriadrf.org/t/limesdr-high-sample-rate-time-series-dropout/5776 "2020-02-18T09:58:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Pallin](https://avatars.discourse-cdn.com/v4/letter/p/c0e974/32.png) [@Pallin](https://discourse.myriadrf.org/u/Pallin)\
**Post date:** [18 February 2020 09:58 UTC](https://discourse.myriadrf.org/t/limesdr-high-sample-rate-time-series-dropout/5776/1 "2020-02-18T09:58:19Z")

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Hello all,  
I’m using a LimeSDR usb as a RF reciever with GNU radio and have noticed that at high sample rates (40 MHz) that there is a drop out in the IQ series. It seems constistantly spaced at ~12 us and occurs in both reciver channels at the same time so I was thinking it was some sort of buffer issue? Has anyone come across this before and would anyone be able to help? Any advice is welcome, pictures included below:  
This is my gnu flowgraph for reference, I have a little transmitter nearby at that frequency.

 ![gnuflowgraph](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/5/55637cc61145691b8d2af54d86e56363ad4f3595.jpeg)

This is the timeseries. Channels are at different levels because of an antenna length missmatch but notice the vertical lines in the plot.

 ![timeseries](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/5/5b25201f14fb96deb87a972be99fc2154644bacb.jpeg)

This is zooming in on one of those lines, where the data is dropping. You can see both channels drop synchronously.

 ![timeserieszoomed](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/b/be94822ea3f26454cfe2479b4ce316169d007708.jpeg)

Thanks,  
Pallin

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**Author:** ![BlackF](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/blackf/32/3251_2.png) [@BlackF](https://discourse.myriadrf.org/u/BlackF)\
**Post date:** [18 February 2020 12:59 UTC](https://discourse.myriadrf.org/t/limesdr-high-sample-rate-time-series-dropout/5776/2 "2020-02-18T12:59:19Z")

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Are you sure you’re not hitting any CPU limitations? Probably you should also use a throttle block.

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<div class="post-metadata">

**Author:** ![Pallin](https://avatars.discourse-cdn.com/v4/letter/p/c0e974/32.png) [@Pallin](https://discourse.myriadrf.org/u/Pallin)\
**Post date:** [18 February 2020 14:56 UTC](https://discourse.myriadrf.org/t/limesdr-high-sample-rate-time-series-dropout/5776/3 "2020-02-18T14:56:36Z")

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Thanks for your reply but I found my problem in that I had used the wrong usb cable (2 not 3)! Still getting some data drops but I can live with it for now.