# Simple sinewave strangeness

**URL:** <https://discourse.myriadrf.org/t/simple-sinewave-strangeness/1443>\
**Category:** LimeSDR\
**Created:** [10 July 2017 01:24 UTC](https://discourse.myriadrf.org/t/simple-sinewave-strangeness/1443 "2017-07-10T01:24:30Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![mzs](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/mzs/32/2678_2.png) [@mzs](https://discourse.myriadrf.org/u/mzs)\
**Post date:** [10 July 2017 13:26 UTC](https://discourse.myriadrf.org/t/simple-sinewave-strangeness/1443/6 "2017-07-10T13:26:21Z")

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From the “LMS7002M DataSheet” -  
“RX analog filters are tunable from 0.7 MHz to 80 MHz.”  
“The TX filtering chain pass band is tunable from 2 MHz to 80 MHz”

So 48kHz samplerates in your flowgraphs is not good.

Those error messages are coming from here at a guess, and the limits look to be slightly different than those defined in the LMS7002M datasheet:

> <https://github.com/myriadrf/LimeSuite/blob/master/src/lms7002m/LMS7002M_filtersCalibration.cpp#L24>

  

> <https://github.com/myriadrf/LimeSuite/blob/master/src/lms7002m/LMS7002M_filtersCalibration.cpp#L109>

  

> <https://github.com/myriadrf/LimeSuite/blob/master/src/lms7002m/LMS7002M_filtersCalibration.cpp#L526>

  

> <https://github.com/myriadrf/LimeSuite/blob/master/src/lms7002m/LMS7002M_filtersCalibration.cpp#L873>

Another thing you may want to look into if the noise is still present using sensible sample rates is to try a USB cable with better shielding, noise could be coming from USB 3.0. Or from the PC, try moving the LimeSDR further away.

> **[USB 3.0\* Radio Frequency Interference on 2.4 GHz Devices](https://www.intel.com/content/www/us/en/products/docs/io/universal-serial-bus/usb3-frequency-interference-paper.html)**
>
> White Paper: Notice of certain USB 3.0\* devices and cables causing radio frequency interference to wireless devices operating in the 2.4 GHz ISM band.

  

> **[USB 3.0 | Radio frequency interference](https://en.wikipedia.org/wiki/USB_3.0#Radio_frequency_interference)**
>
> USB 3.0 devices and cables may interfere with wireless devices operating in the 2.4 GHz ISM band. This may result in a drop in throughput or complete loss of response with Bluetooth and Wi-Fi devices. Various strategies can be applied to resolve the problem, ranging from simple solutions such as increasing the distance of USB 3.0 devices from Wi-Fi routers and Bluetooth devices, to applying additional shielding around internal computer components.
> There were some devices (for example Vivo Xpla...

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