# USRP2 with 10MHz Function Generator

**URL:** <https://www.ruby-forum.com/t/usrp2-with-10mhz-function-generator/203021>\
**Category:** GNU Radio\
**Created:** [February 10, 2011, 6:36pm UTC](https://www.ruby-forum.com/t/usrp2-with-10mhz-function-generator/203021 "2011-02-10T18:36:35Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\
**Post date:** [February 10, 2011, 6:36pm UTC](https://www.ruby-forum.com/t/usrp2-with-10mhz-function-generator/203021/1 "2011-02-10T18:36:35Z")

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Hi

1. 

```
 I am interested to use Function Generator with Square Waveform 

```

out put as a Reference Clock input (10 MHZ)to USRP2. Is this a fine  
approach to do so…?  
2) What is the relation ship between PPS IN and REF Clock input of  
USRP2?

Waiting for early Response

Zimran Rafique

Hi

1. 

```
 I am interested to use Function Generator with Square Waveform 

```

out put as a Reference Clock input (10 MHZ)to USRP2. Is this a fine  
approach to do so…?  
2) What is the relation ship between PPS IN and REF Clock input of  
USRP2?

Waiting for early Response

Zimran Rafique

Hi

1. 

```
 I am interested to use Function Generator with Square Waveform 

```

out put as a Reference Clock input (10 MHZ)to USRP2. Is this a fine  
approach to do so…?  
2) What is the relation ship between PPS IN and REF Clock input of  
USRP2?

Waiting for early Response

Zimran Rafique

Hi

1. 

```
 I am interested to use Function Generator with Square Waveform 

```

out put as a Reference Clock input (10 MHZ)to USRP2. Is this a fine  
approach to do so…?  
2) What is the relation ship between PPS IN and REF Clock input of  
USRP2?

Waiting for early Response

Zimran Rafique

Hi

1. 

```
 I am interested to use Function Generator with Square Waveform 

```

out put as a Reference Clock input (10 MHZ)to USRP2. Is this a fine  
approach to do so…?  
2) What is the relation ship between PPS IN and REF Clock input of  
USRP2?

Waiting for early Response

Zimran Rafique

---

<div class="post-metadata">

**Author:** ![hafiz\_zimran](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/ed8c4c/32.png) [@hafiz\_zimran](https://www.ruby-forum.com/u/hafiz_zimran)\
**Post date:** [February 10, 2011, 6:56pm UTC](https://www.ruby-forum.com/t/usrp2-with-10mhz-function-generator/203021/2 "2011-02-10T18:56:03Z")

</div>

> 1. 
> 
> ```
> I am interested to use Function Generator with Square Waveform out put 
> 
> ```

as a Reference Clock input (10 MHZ)to USRP2. Is this a fine approach to do so…?

[http://www.ettus.com/uhd\_docs/manual/html/usrp2.html#ref-clock-10mhz](http://www.ettus.com/uhd_docs/manual/html/usrp2.html#ref-clock-10mhz)

> 1. 
> 
> ```
> What is the relation ship between PPS IN and REF Clock input of USRP2?
> 
> ```

The PPS should be in the same clock domain as the reference clock.

-josh

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<div class="post-metadata">

**Author:** ![hafiz\_zimran](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/ed8c4c/32.png) [@hafiz\_zimran](https://www.ruby-forum.com/u/hafiz_zimran)\
**Post date:** [February 15, 2011, 8:44pm UTC](https://www.ruby-forum.com/t/usrp2-with-10mhz-function-generator/203021/3 "2011-02-15T20:44:13Z")

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On 02/09/2011 05:15 PM, hafiz zimran wrote:

> Hi
> 
> 1. 
> 
> ```
> I am interested to use Function Generator with Square Waveform
> 
> ```
> 
> out put as a Reference Clock input (10 MHZ)to USRP2. Is this a fine  
> approach to do so…?

Yes

> 1. 
> 
> ```
> What is the relation ship between PPS IN and REF Clock input of
> 
> ```
> 
> USRP2?

The PPS\_IN should be in the same clock domain as the 10 MHz if you plan  
to synchronize multiple USRPs to each other. Otherwise, you can use any  
PPS signal.

Matt

---

<div class="post-metadata">

**Author:** ![hafiz\_zimran](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/ed8c4c/32.png) [@hafiz\_zimran](https://www.ruby-forum.com/u/hafiz_zimran)\
**Post date:** [February 15, 2011, 9:20pm UTC](https://www.ruby-forum.com/t/usrp2-with-10mhz-function-generator/203021/4 "2011-02-15T21:20:01Z")

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On Tue, 2011-02-15 at 11:43 -0800, Matt E. wrote:

> > 1. 
> > 
> > ```
> > What is the relation ship between PPS IN and REF Clock input of
> > 
> > ```
> > 
> > USRP2?
> 
> The PPS\_IN should be in the same clock domain as the 10 MHz if you plan  
> to synchronize multiple USRPs to each other. Otherwise, you can use any  
> PPS signal.
> 
> Matt

I actually synchronize multiple USRPs with unaligned 10MHz and pps.  
Sometimes two USRPs are offset one clock cycle (10ns) but that is OK  
for my application. Of course, I need also to consider that one pps  
interval will not be exactly 100e6 clock cyckles

BR/  
Per