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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 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 > > > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts