# LimeSDR transmits noise (or maybe harmonics) at low sample rates

**URL:** <https://discourse.myriadrf.org/t/limesdr-transmits-noise-or-maybe-harmonics-at-low-sample-rates/1468>\
**Category:** LimeSDR\
**Created:** [15 July 2017 09:28 UTC](https://discourse.myriadrf.org/t/limesdr-transmits-noise-or-maybe-harmonics-at-low-sample-rates/1468 "2017-07-15T09:28:55Z")\
**Posts on this page:** 1\
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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:** [15 July 2017 10:12 UTC](https://discourse.myriadrf.org/t/limesdr-transmits-noise-or-maybe-harmonics-at-low-sample-rates/1468/2 "2017-07-15T10:12:00Z")

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The datasheet says 2 MHz as the minimum bandwidth for TX and the source code says 5 MHz the minimum TX Low Pass Filter.

> [@Simple sinewave strangeness](https://discourse.myriadrf.org/t/simple-sinewave-strangeness/1443/6):
>
> 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: 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 bett…

So I’d be inclined to change your sample rate to 5 MSPS and see if the problem persists.

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