[time-nuts] Help w/integration problem

John Ackermann N8UR jra at febo.com
Mon Jan 2 10:02:28 EST 2006


Hi Mike --

Actually, I'm most likely to convert it to Perl or Python or something
to run on my Linux boxes.  I'll be happy to make the port available to
anyone who wants it (no guarantees when it'll be done, though).

73,
John
----

Mike Feher said the following on 01/02/2006 09:51 AM:
> John -
> 
> Do you also need GW Basic? I'll FTP the programs and send the URL shortly.
> 73 - Mike
> 
>  
> Mike B. Feher, N4FS
> 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 Ackermann N8UR
> Sent: Monday, January 02, 2006 9:09 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Help w/integration problem
> 
> Hi Mike --
> 
> I can't speak for John, but I'd sure find that program useful.
> 
> 73,
> John
> ----
> 
> Mike Feher said the following on 01/02/2006 08:10 AM:
> 
>>John -
>>
>>I wrote a program about 20 years ago to calculate the total integrated
> 
> noise
> 
>>power from the individual power spectrum density points. It is in GW Basic
>>and I still use it almost daily. Let me know if you would like it. 73 -
> 
> Mike
> 
>> 
>>Mike B. Feher, N4FS
>>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 3:00 AM
>>To: Discussion of precise time and frequency measurement
>>Subject: [time-nuts] Help w/integration problem
>>
>>Does anyone have a piece of C (BASIC, whatever) code that turns an array
> 
> of
> 
>>dBc/Hz values into integrated RMS noise?
>>
>>I'm trying to use a simple rectangular integrator to divide a log-log plot
>>into "bins":
>>
>>  for (i=L_column; i < U_column-1; i++)
>>     {
>>     sum += ((value[i] - ((value[i] - value[i+1]) / 2.0)) *
>>(frequency[i+1] - frequency[i]));
>>     }
>>
>>This just takes the midpoint dBc/Hz value between successive columns of a
>>phase-noise plot, multiplies it by the frequency step between the columns
> 
> in
> 
>>question, and sums the result for all columns in the range of interest.
>>
>>The output of this process, when I feed a typical noise graph with values
>>around -110 dBc/Hz to it, with frequency values at the lower and upper
>>limits of 1000 and 10000 Hz, is around -1E+6.  What I'd *like* is a value
>>corresponding to the "-63 dBc" value cited on pages 7 and 8 in this
> 
> Zarlink
> 
>>app note:
>>
>>http://assets.zarlink.com/CA/Phase_Noise_and_Jitter_Article.pdf
>>
>>In this note, the author shows a noise curve similar to the ones I'm
> 
> working
> 
>>with, and magically pulls -63 dBc out of the ether with no explanation of
>>the integration process that obtained it.  (What does it mean, in the
>>author's words, to take the area "under" a phase-noise curve, anyway?
>>What's the bottom dBc/Hz value?)
>>
>>Being from the instant-gratification generation, I really don't want (and
>>won't understand) a calculus lecture.  I want the 5 lines of code that do
>>the integration. :-)  This is for the next release of my freeware GPIB
>>noise-measurement app, so your karma will be integrated along with the
> 
> noise
> 
>>if you're able to help!
>>
>>-- john, KE5FX
>>
>>
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> 
> 
> 
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