# TX signal sample rate issues

**URL:** <https://discourse.myriadrf.org/t/tx-signal-sample-rate-issues/5896>\
**Category:** LimeSDR\
**Created:** [18 March 2020 22:26 UTC](https://discourse.myriadrf.org/t/tx-signal-sample-rate-issues/5896 "2020-03-18T22:26:22Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![Garmus](https://avatars.discourse-cdn.com/v4/letter/g/a183cd/32.png) [@Garmus](https://discourse.myriadrf.org/u/Garmus)\
**Post date:** [27 March 2020 12:35 UTC](https://discourse.myriadrf.org/t/tx-signal-sample-rate-issues/5896/7 "2020-03-27T12:35:25Z")

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Hey @TehWan,  
Thanks for posting such descriptive issue.

To check the problem out I first did some basic tests using gr-limesdr and NCO. My basic test flowgraph was Noise source-\>LPF(500kHz)-\>LimeSDR(TX) on transmit side and LimeSDR(RX)(different board)-\>QT GUI sink. As expected, the whole signal bandwidth is 1MHz and when I set TX NCO to 1MHz signal moves to the desired location without change of bandwidth.

After downloading and trying it with your provided signal I noticed the problem you were describing, meaning that the bandwidth definitely increases when using NCO. Looking at time graph of your signal though, it sometimes gets above [-1;1] range and multiplying signal by 0.8 fixes the bandwidth problem(see screenshots below).

With full range of your signal, NCO on RX side and Xlating on TX side:

 ![xlating(nco)_limenco_fullrange](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/a/a570d205b2cd4b6694305037a77df2acfb1b4638.png)  
When your signal is multiplied by 0.8, NCO on RX side and Xlating on TX side:  
 ![xlating(nco)_limenco](https://canada1.discourse-cdn.com/flex034/uploads/myriadrf/original/2X/7/748bee8c1bb777c07c40b008cb88c20bc7d46fdb.png)

Regards,  
Richard

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