# Limitations of Dampening factor in PLL

**URL:** <https://www.ruby-forum.com/t/limitations-of-dampening-factor-in-pll/237583>\
**Category:** GNU Radio\
**Created:** [November 20, 2013, 2:18am UTC](https://www.ruby-forum.com/t/limitations-of-dampening-factor-in-pll/237583 "2013-11-20T02:18:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [November 20, 2013, 2:18am UTC](https://www.ruby-forum.com/t/limitations-of-dampening-factor-in-pll/237583/1 "2013-11-20T02:18:02Z")

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Can somebody explain why the dampening factor inside  
gr::blocks::control\_loop is clamped to being (0, 1)? I understand why  
the  
default has been set to sqrt(2)/2 and not provided from the constructor,  
I  
just cannot see why it is limited to this range.

Thank you in advance for your help,

Michael B.

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**Author:** ![michaelb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b19c9b/32.png) [@michaelb](https://www.ruby-forum.com/u/michaelb)\
**Post date:** [November 20, 2013, 2:32am UTC](https://www.ruby-forum.com/t/limitations-of-dampening-factor-in-pll/237583/2 "2013-11-20T02:32:09Z")

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On Tue, Nov 19, 2013 at 8:16 PM, Michael B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Can somebody explain why the dampening factor inside  
> gr::blocks::control\_loop is clamped to being (0, 1)? I understand why the  
> default has been set to sqrt(2)/2 and not provided from the constructor, I  
> just cannot see why it is limited to this range.
> 
> Thank you in advance for your help,
> 
> Michael B.

No reason at all. Probably just over-zealous copy-and-paste. I’ll fix  
this.

Thanks for the report.

Tom

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**Author:** ![michaelb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b19c9b/32.png) [@michaelb](https://www.ruby-forum.com/u/michaelb)\
**Post date:** [November 20, 2013, 5:32pm UTC](https://www.ruby-forum.com/t/limitations-of-dampening-factor-in-pll/237583/3 "2013-11-20T17:32:22Z")

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Tom,

Thanks for the quick response on this.

Michael