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@febo.com [mailto:time-nuts-bounces@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@febo.com [mailto:time-nuts-bounces@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

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Hi Poul,

In my opinion, the only obstacle to becoming an
electronics hobbyist is the same one that has always
been there, and that is interest.  If you are interested,
you will find a way to play.

-Chuck

Poul-Henning Kamp wrote:

Just look at what people have done with the ZipIt.  They have wired
serial ports into it (by soldering onto surface mount resistors).
They have even added a MMC/SD card by hijacking some of the gpio pins
that have come out (again, by soldering onto surface mount resistors)
and hot-glueing the MMC/SD socket to the RF shielding.

http://elinux.org/wiki/ZipIt contains all the details.

Or look at all the TiVO hacking done, despite efforts to stop it.

Or the iOpener hacking a few years ago.

Or any of a dozen other Linux boxes that people have posted how-tos on
burning new firmware.

Hacking is alive and well.  People are willing to do it.  It is a heck
of a lot different than when we were young, but the same spirit lives
on.

Warner

"Bill Hawkins" bill@iaxs.net wrote:

I can tell you that when NTSC broadcasts cease in the next couple of
years, my kids will no longer have access to TV at home.  And I think
that's a Good Thing.

I'd like to think that other kids will lose TV, but realistically
probably 90% of low-income kids already have satellite or cable or
HDTV at home.

One very real problem: everything of "value" these days has
a sheen/style/flash on top, and things don't register with kids
without that sheen.

Tim.

Mike,

Visual Basic is the normal evolution for old Basic programs like yours.
You can directly reuse the source code for most of your algorithms, but
you will have to rewrite the user interface. VB makes it really easy to
generate a good looking visual interface that will make your program
look professional. Of course, VB is Windows only.

The most popular versions (in my opinion, not a scientific study :-) are:

1. VB 3.0, the oldest version that one might want to consider using
   because it was quite popular and useful, and I happen to have an old
   legitimate copy that I do not use anymore and I would be glad to let you
   have it for you to play with (and do such silly things as convert your
   old DOS BASIC programs...) if I can find it,
2. VB 6.0, the one I am currently using most, because it is WIDELY
   popular and used by a lot of professional software writers and very well
   supported by various groups on the Internet, and
3. VB.NET, the current version, where VB stands for Very Bloated. Nuf said.

Being a MSDN licensee, I have access to all versions but I prefer VB 6.0
for general Windows software.

Let me know if you are interested, I will dig up my old VB 3.0 disks.

Didier KO4BB

Mike Feher wrote:

Didier Juges wrote:

Deleted mikes comments

Are any of the versions of Visual basic still sold that will run on my
machine running Win 98se ?
I could always go to DOS but hesitate to order a program and then find
it won't work
on my computer, My workbench computer runs fine with 98se.

Thanks
Bill K7NOM

Didier -

I appreciate your offer and will take you up on it. It seems like around 10
or more years ago VB came bundled with the software package that we got with
the computers of the time. Being hard headed then, as I am now, I was just
not in the mood to learn how to use it, especially since Basic at that time
was still easily usable on most machines. The problem is, I have some Basic
programs that have several thousand lines of code, not like the simple one I
posted for phase noise. I do not know if I really want to take the time to
convert them manually from regular basic to VB considering I may only use
them once or twice a year. Let me know how much to send to cover your
expenses. Thanks & 73 - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Didier Juges
Sent: Wednesday, January 04, 2006 12:12 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Help w/integration problem

Mike,

Visual Basic is the normal evolution for old Basic programs like yours.
You can directly reuse the source code for most of your algorithms, but
you will have to rewrite the user interface. VB makes it really easy to
generate a good looking visual interface that will make your program
look professional. Of course, VB is Windows only.

The most popular versions (in my opinion, not a scientific study :-) are:

1. VB 3.0, the oldest version that one might want to consider using
   because it was quite popular and useful, and I happen to have an old
   legitimate copy that I do not use anymore and I would be glad to let you
   have it for you to play with (and do such silly things as convert your
   old DOS BASIC programs...) if I can find it,
2. VB 6.0, the one I am currently using most, because it is WIDELY
   popular and used by a lot of professional software writers and very well
   supported by various groups on the Internet, and
3. VB.NET, the current version, where VB stands for Very Bloated. Nuf said.

Being a MSDN licensee, I have access to all versions but I prefer VB 6.0
for general Windows software.

Let me know if you are interested, I will dig up my old VB 3.0 disks.

Didier KO4BB

Mike Feher wrote:

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time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

I am familiar with the arguments. I think your solution
is a good one. The goal is to remove ambiguity and
your using both MJD and UTC (or TAI) does that. It's
always a pain to compute accurate time intervals when
leap seconds have to be considered.

Strictly speaking MJD (= JD - 2400000.5) is based on
an astronomical timescale such as UT1. In this case
a leap second has no effect since the UT timescales
have no leap seconds. Astronomers appear to avoid
using MJD altogether.

The time metrology community, on the other hand,
uses MJD a lot and in practice it's based on UTC.
And so one can ponder, as you mentioned, if the
fractional MJD value for 12/31/2005 should be based
on a 86400 s or 86401 s day.

The advice I was given was to just leave the ambiguity
alone; unless it really, really mattered, in which case
you the author should specify which timescale which
you are basing your MJD on, or not use MJD at all.
I've never run into a case myself where it mattered,
nor seen a paper where a graph axis or numerical
result depended in which timescale the MJD values
were based on.

It is interesting to note that if leap seconds were to be
eliminated the ambiguity between a true UT-based
MJD and a practical UTC-based MJD would be further
exposed. Still, if you consider how the timing community
generally uses MJD I suspect you'd have to look hard to
find a graph that would be off by as much as one pixel.
The other approach is the space and timing communities
could by accident or convention redefine MJD as a
UTC-based time value, leaving JD to the astronomers
as a true, pure UT-based time value. It's just one of many
subtle but non-showstopper details that would show up
in the next centuries if leap seconds were retired.

/tvb
http://www.leapsecond.com/time-nuts.htm