[time-nuts] Help w/integration problem
Mike Feher
mfeher at eozinc.com
Tue Jan 3 12:36:31 EST 2006
Well, do not feel bad if you do not have a ready answer to my
question/dilemma. I have been on the phone to some of the top people in this
field at MIT LL for the past 3 hours. While they all appreciate my concern
none had an answer. But, I feel like I am converging on an answer, even if
it is of my own making. - Mike
Mike B. Feher
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Mike Feher
Sent: Monday, January 02, 2006 11:36 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Help w/integration problem
John -
Thanks, good basic stuff. Right now my biggest concern is the amount of
acceptable phase jitter for a given data rate for higher order modulations.
I know that the rule of thumb is not to exceed 10% of the Euclidian distance
between phase points in the constellation, but, how do you obtain the RMS
phase jitter for a given symbol rate? I have seen literature that states you
have to integrate all the way to Rs, but for the higher orders above BPSK, I
think you only need to integrate to Rs/2. Naturally you still have to add 3
dB to the number prior to calculating the phase jitter in degrees due to the
double sideband. I have pretty much convinced myself that going to Rs/2 is
the upper bound of the integral. The question is, what is the lower bound? I
have seen numbers as low as 1%, which seem absurd to me. I think even 10 %
would probably not degrade BER for a given Eb/No to make a difference. Any
ideas appreciated. - Thanks - Mike
Mike B. Feher
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of John Miles
Sent: Monday, January 02, 2006 11:14 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Help w/integration problem
http://pdfserv.maxim-ic.com/en/an/AN3359.pdf is the Maxim note I was
referring to.
This HP app note, describing an advanced noise-measurement program for the
8568A, is excellent as well:
http://www.speakeasy.net/~jmiles1/an270-2.pdf
With a graph acquired from the junker 8568A I bought for GPIB work, I'm
getting essentially-identical results to what they show in figure 4. Makes
me a lot more confident in the math, as well as the condition of my $450
8568A.
-- john, KE5FX
> Could someone please give me a reference for the Maxim
> application note that
> has been mentioned several times? I would like to see it, as when
> I wrote my
> program it was based on my own knowledge, and I want to make sure
> we are in
> agreement. Although, in the many years that I have used my program I have
> not found it to be faulty. Pretty straight forward stuff really.
> But, there
> have been times in the past when I thought that, and made
> mistakes. - Thanks
> - Mike
>
>
> Mike B. Feher
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
>
>
>
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