# phase error variance to rms phase error

Started by November 2, 2010
```hello,
i have an expression that gives the phase error variance of QPSK system as
follows:\
phase error variance=(Aif/sqrt(2*pi*n))*I0(-Aif/2*n)
here, Aif=IF amplitude,
n=noise component variance,
I0=modified bessel function of the 1st kind
How can i calculate rms phase error of that system from this phase error
variance

thanks
```
```On 11/02/2010 01:54 PM, sunshineshuvo wrote:
> hello,
> i have an expression that gives the phase error variance of QPSK system as
> follows:\
> phase error variance=(Aif/sqrt(2*pi*n))*I0(-Aif/2*n)
> here, Aif=IF amplitude,
> n=noise component variance,
> I0=modified bessel function of the 1st kind
>   How can i calculate rms phase error of that system from this phase error
> variance

What does the word "variance" mean in statistics?

What does the abbreviation "RMS" stand for in signal processing?

Why have you just asked a really obvious question?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
```
```>On 11/02/2010 01:54 PM, sunshineshuvo wrote:
>> hello,
>> i have an expression that gives the phase error variance of QPSK system
as
>> follows:\
>> phase error variance=(Aif/sqrt(2*pi*n))*I0(-Aif/2*n)
>> here, Aif=IF amplitude,
>> n=noise component variance,
>> I0=modified bessel function of the 1st kind
>>   How can i calculate rms phase error of that system from this phase
error
>> variance
>
>What does the word "variance" mean in statistics?
>
>What does the abbreviation "RMS" stand for in signal processing?
>
>Why have you just asked a really obvious question?
>
>--
>
>Tim Wescott
>Wescott Design Services
>http://www.wescottdesign.com

Maybe its a phase he's going through.

Steve

```