On 1/12/14 6:03 PM, gyansorova@gmail.com wrote:
> On Monday, January 13, 2014 9:29:05 AM UTC+13, robert bristow-johnson wrote:
>> On 1/12/14 3:10 PM, gyansorova@gmail.com wrote:
>>
>>> Unless the interference changes with frequency then all you need is a notch filter.
>>
>> somebuddy's gotta tune it.
>
> But if the freq is fixed so what. Trim it in. I suppose if you already have a DSP in place and plenty grunt then maybe an LMS.

or your DSP can be a notch and some other alg to sense it's outa tune 
and to slowly adjust the resonant frequency and maybe the Q and the 
depth.  like a parametric EQ.

i thought that's how that Sabine Feedback Exterminator worked.  not an 
LMS, which i don't think worked so well on the live stage.


-- 

r b-j                  rbj@audioimagination.com

"Imagination is more important than knowledge."

Randy Yates <yates@digitalsignallabs.com> writes:

> Eric Huay <e.huay@nospam.com> writes:
>
>> I'm trying to implement an interference cancellation using linear prediction.
>> A block diagramtherefore is shown in [1]. The adaptive algorithm as a
>> LMS (least mean square)-algorithm. This works quite well!
>>
>> The overall system is something like notch-filter. How can I obtain
>> this magnitude response of the overall system?
>>
>> Thank you and best regards
>> Eric
>
> In the frequency domain,
>
>   E(z) = D(z) - F(z) * z^(-delta) * D(z)
>        = (1 - H(z) * z^(-delta)) * D(z)
>
> and so
>
>   H(z) = E(z) / D(z)
>        = 1 - H(z) * z^(-delta)
>
> where F(z) is the adaptive filter response.

Correction:

In the frequency domain,

  E(z) = D(z) - F(z) * z^(-delta) * D(z)
       = (1 - F(z) * z^(-delta)) * D(z)

and so

  H(z) = E(z) / D(z)
       = 1 - F(z) * z^(-delta)

where F(z) is the adaptive filter response.
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com

Eric Huay <e.huay@nospam.com> writes:

> I'm trying to implement an interference cancellation using linear prediction.
> A block diagramtherefore is shown in [1]. The adaptive algorithm as a
> LMS (least mean square)-algorithm. This works quite well!
>
> The overall system is something like notch-filter. How can I obtain
> this magnitude response of the overall system?
>
> Thank you and best regards
> Eric

In the frequency domain,

  E(z) = D(z) - F(z) * z^(-delta) * D(z)
       = (1 - H(z) * z^(-delta)) * D(z)

and so

  H(z) = E(z) / D(z)
       = 1 - H(z) * z^(-delta)

where F(z) is the adaptive filter response.
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com

On Monday, January 13, 2014 9:29:05 AM UTC+13, robert bristow-johnson wrote:
> On 1/12/14 3:10 PM, gyansorova@gmail.com wrote:
> 
> > On Sunday, January 12, 2014 10:58:42 PM UTC+13, Eric Huay wrote:
> 
> >> I'm trying to implement an interference cancellation using linear prediction.
> 
> >>
> 
> >> A block diagramtherefore is shown in [1]. The adaptive algorithm as a
> 
> >>
> 
> >> LMS (least mean square)-algorithm. This works quite well!
> 
> >>
> 
> >>
> 
> >>
> 
> >> The overall system is something like notch-filter. How can I obtain
> 
> >>
> 
> >> this magnitude response of the overall system?
> 
> >>
> 
> >>
> 
> >>
> 
> >> Thank you and best regards
> 
> >>
> 
> >> Eric
> 
> >>
> 
> >>
> 
> >>
> 
> >> [1] http://goo.gl/UtAkgM
> 
> >
> 
> > Unless the interference changes with frequency then all you need is a notch filter.
> 
> 
> 
> somebuddy's gotta tune it.
> 
> 
> 
> -- 
> 
> 
> 
> r b-j                  rbj@audioimagination.com
> 
> 
> 
> "Imagination is more important than knowledge."

But if the freq is fixed so what. Trim it in. I suppose if you already have a DSP in place and plenty grunt then maybe an LMS.

On 1/12/14 3:10 PM, gyansorova@gmail.com wrote:
> On Sunday, January 12, 2014 10:58:42 PM UTC+13, Eric Huay wrote:
>> I'm trying to implement an interference cancellation using linear prediction.
>>
>> A block diagramtherefore is shown in [1]. The adaptive algorithm as a
>>
>> LMS (least mean square)-algorithm. This works quite well!
>>
>>
>>
>> The overall system is something like notch-filter. How can I obtain
>>
>> this magnitude response of the overall system?
>>
>>
>>
>> Thank you and best regards
>>
>> Eric
>>
>>
>>
>> [1] http://goo.gl/UtAkgM
>
> Unless the interference changes with frequency then all you need is a notch filter.

somebuddy's gotta tune it.

-- 

r b-j                  rbj@audioimagination.com

"Imagination is more important than knowledge."

On Sunday, January 12, 2014 10:58:42 PM UTC+13, Eric Huay wrote:
> I'm trying to implement an interference cancellation using linear prediction.
> 
> A block diagramtherefore is shown in [1]. The adaptive algorithm as a 
> 
> LMS (least mean square)-algorithm. This works quite well!
> 
> 
> 
> The overall system is something like notch-filter. How can I obtain 
> 
> this magnitude response of the overall system?
> 
> 
> 
> Thank you and best regards
> 
> Eric
> 
> 
> 
> [1] http://goo.gl/UtAkgM

Unless the interference changes with frequency then all you need is a notch filter. 

I'm trying to implement an interference cancellation using linear prediction.
A block diagramtherefore is shown in [1]. The adaptive algorithm as a 
LMS (least mean square)-algorithm. This works quite well!

The overall system is something like notch-filter. How can I obtain 
this magnitude response of the overall system?

Thank you and best regards
Eric

[1] http://goo.gl/UtAkgM