[time-nuts] PIC Divider Performance (was Re: time-nuts Digest, Vol 56, Issue 71)

Ulrich Bangert df6jb at ulrich-bangert.de
Tue Mar 31 03:20:34 EDT 2009


Gents,

after the discussion of the pic pps divider's properties let me add that on

http://www.ulrich-bangert.de/html/downloads.html

you can find a version of the pps divider that has been adopted to the Atmel
AVR Mega world. Two versions are available, one uses port A and a second
uses port D for the outputs. In contrast to the original design the 100 kHz
output has a near perfect 1:1 duty cycle. In the zips you find complete
WinAVR projects.

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Poul-Henning Kamp
> Gesendet: Dienstag, 31. Marz 2009 07:30
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] PIC Divider Performance (was Re: 
> time-nuts Digest,Vol 56, Issue 71)
> 
> 
> In message <49D16637.60502 at febo.com>, John Ackermann N8UR writes:
> 
> >Therefore, the PIC divider is a bit above the 5370B noise floor, but 
> >not much.
> 
> Many years ago, I did a similar experiment, but to eliminate 
> the timebases from the measurement I used the PPS output as 
> start and the 10MHz input frequency as stop.
> 
> That way only the delay & jitter of the PPSDIV is measured (+ 
> cables & counters obviously).
> 
> The result were of similar magnitude.
> 
> Poul-Henning
> 
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe    
> Never attribute to malice what can adequately be explained by 
> incompetence.
> 
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