# Available sample rates for USRP2

**URL:** <https://www.ruby-forum.com/t/available-sample-rates-for-usrp2/213190>\
**Category:** GNU Radio\
**Created:** [October 26, 2011, 3:17am UTC](https://www.ruby-forum.com/t/available-sample-rates-for-usrp2/213190 "2011-10-26T03:17:49Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dubstep](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/cdc98d/32.png) [@dubstep](https://www.ruby-forum.com/u/dubstep)\
**Post date:** [October 26, 2011, 3:17am UTC](https://www.ruby-forum.com/t/available-sample-rates-for-usrp2/213190/1 "2011-10-26T03:17:49Z")

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When I use uhd\_fft.py -s 8M -f …

It reported that

UHD Warning:

```
The hardware does not support the requested RX sample rate:

Target sample rate: 8.000000 MSps

Actual sample rate: 7.692308 MSps

```

I am wondering how the actual rate 7.692308M is determined?

Is there any formula that I can use to ascertain that a given sample  
rate is  
available on USRP2?

Thanks

KZ

---

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**Author:** ![Kyle\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/6f9a4e/32.png) [@Kyle\_Z](https://www.ruby-forum.com/u/Kyle_Z)\
**Post date:** [October 26, 2011, 3:22am UTC](https://www.ruby-forum.com/t/available-sample-rates-for-usrp2/213190/2 "2011-10-26T03:22:10Z")

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On Tue, Oct 25, 2011 at 6:18 PM, Kyle Z. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Actual sample rate: 7.692308 MSps
> 
> I am wondering how the actual rate 7.692308M is determined?
> 
> Is there any formula that I can use to ascertain that a given sample rate is  
> available on USRP2?

100Msps / x, where x is an integer (in your case, 13).

–n

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<div class="post-metadata">

**Author:** ![Kyle\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/6f9a4e/32.png) [@Kyle\_Z](https://www.ruby-forum.com/u/Kyle_Z)\
**Post date:** [October 26, 2011, 3:22am UTC](https://www.ruby-forum.com/t/available-sample-rates-for-usrp2/213190/3 "2011-10-26T03:22:10Z")

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On 10/25/2011 06:18 PM, Kyle Z. wrote:

> ```
> Actual sample rate: 7.692308 MSps
> 
> ```
> 
> I am wondering how the actual rate 7.692308M is determined?
> 
> Is there any formula that I can use to ascertain that a given sample rate is  
> available on USRP2?

Only integer divisor rates of the master clock is possible. In this case  
100Mhz/decimation = sample rate.

Querying the possible sample rates will be part of my next API revision.

-Josh