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Thread: MXA and N6153A group delay smoothing ...


Permlink Replies: 4 - Pages: 1 - Last Post: Jan 12, 2012 2:39 AM Last Post By: kappasm Threads: [ Previous | Next ]
kappasm

Posts: 15
Registered: 06/01/07
MXA and N6153A group delay smoothing ...
Posted: Dec 31, 2011 3:32 AM
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Hi,

I have MXA with DVB-T Application N6153A. I have to adjust a filter combiner and normally I use the "group delay". Acting on liner precorrector I change curve of precorrection to obtain lower group delay on full span portant.

But there is a problem, the measure does not much intelligible :

Image

It is not possible to introduce a configurable smoothing ?

"Rohde & Swartz" signal smooting is default :

Image

Thanks very much.

Kappasm.
tabbott


Posts: 1,483
Registered: 07/24/09
Re: MXA and N6153A group delay smoothing ...
Posted: Jan 4, 2012 12:48 PM   in response to: kappasm in response to: kappasm
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Hi Kappasm -

With X-Series Signal Analyser software release A.10, we have added parameter ‘aperture’ for DVB-T and DVB-T2 group delay smoothing, the default value is 1%. The result would be okay for most uses. You can use the following SCPI command to adjust it.
:DISPlay:EVM:GD:APERture 0.01 for DVB-T
:DISPlay:EVMTtwo:GD:APERture 0.01 for DVB-T2

So, the aperture will affect the accuracy of the group delay measurement.
When the aperture becomes smaller, the measured group delay approaches the phase derivative more, but the measured error will be enlarged.
When the aperture increases, the accuracy of the measured group delay improves. It increases the smoothing of the group delay trace, but the resolution degrades.

I hope this was helpful -
kappasm

Posts: 15
Registered: 06/01/07
Re: MXA and N6153A group delay smoothing ...
Posted: Jan 7, 2012 2:27 AM   in response to: kappasm in response to: kappasm
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Hi tabbott,

> With X-Series Signal Analyser software release A.10, we have added parameter ‘aperture’ for DVB-T
> and DVB-T2 group delay smoothing, the default value is 1%. The result would be okay for most uses.
> You can use the following SCPI command to adjust it.
> :DISPlay:EVM:GD:APERture 0.01 for DVB-T
> :DISPlay:EVMTtwo:GD:APERture 0.01 for DVB-T2

I can't set aperture from display menu ? From where, I do not find it.

> So, the aperture will affect the accuracy of the group delay measurement.

Ok I agree, but you can not see anything without smoothing ... it is impossible to make a calibration, otherwise what I use ?

Thanks very much.

Kappasm
tabbott


Posts: 1,483
Registered: 07/24/09
Re: MXA and N6153A group delay smoothing ...
Posted: Jan 11, 2012 1:15 PM   in response to: kappasm in response to: kappasm
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Hi Kappasm -

My apologies. The X-Series Signal Analyser software release A.10 will not be available until February 2012.

I can send you the new version if you want to try it - Or you will have to wait until the formal release in a few weeks.

Regards -
kappasm

Posts: 15
Registered: 06/01/07
Re: MXA and N6153A group delay smoothing ...
Posted: Jan 12, 2012 2:39 AM   in response to: kappasm in response to: kappasm
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Hi tabbott,

> The X-Series Signal Analyser software release A.10 will not be available until February 2012.

OK, I'am waiting ...

> I can send you the new version if you want to try it - Or you will have to wait until the formal release in a few weeks.

I'am waiting a new release, what's new in new releases ?

Thanks very much.

Kappasm

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