[time-nuts] Timing Health Monitoring

[Chris Hoffman]

Mr. Sproul: I really like your solution! Do you mind emailing me code and schematics?

Bob, you right: I should be watching slips with a PPS-actuated buffer. For now, I don't have the resources for a ready-made dual-input counter, but the strangest/best things seem to show up at the flea market when I'm least expecting them ;) For now, I will be conducting research on integrating a rudimentary counter on top of Mr. Sproul's design.

Chris: It should be no issue to take your comparator and 'tape' an A/D pin to it for digital monitoring, either (I'm not sure how Bob's design is implemented, but it appears roughly equivalent). Do you have any examples I should be looking for?

-CH

Chris Hoffman
cq.kg6o at gmail.com
http://ar.ctur.us




On Jul 17, 2012, at 11:51 AM, MSproul wrote:

> 
> On Jul 17, 2012, at 11:09 AM, Chris Hoffman, KG6O wrote:
> 
>> 
>> What advice does anyone have on building/finding cheap [visual?] comparison devices to display or detect a timing [lesajo?] from my 10MHz sine wave ports?
>> I am thinking about building an embedded system to automate monitoring, configuration, and alerts... perhaps using an Arduino.
>> 
>> -CH__
> 
> 
> 
> 
> 
> Hi Chris
> I am doing what you are asking about. I have built a Frequency Comparator that compare two10 MHz
> square waves but would probably work with sine waves. I am using a Digilent. Inc. chipKIT Uno32.
> 
>      http://digilentinc.com/Products/Detail.cfm?NavPath=2,892,893&Prod=CHIPKIT-UNO32.
> 
> This board is comparable to the Arduino and most of the shields for the Arduino will work with the chipKIT.
> To program the chipKIT requires the Mpide program from Digilent. The program is free (from the above site)
> AND will program both the Arduino and chipKIT, just select the proper option. No change in source code is required
> to compile for the Arduino or chipKIT. The program looks just like the one from Arduino.
> 
> The attached photo shows the display of my comparator.
> 
> The first line is the name of the source code
> The second line is error between reference and Device under Test and whether the DUT is high or low
> The third line is current time between cycle slips
> The fourth line is the current error and is continually updated during a cycle slip
> 
> The LEDs at the top give a visual presentation of the cycle slips: Left-moving - DUT is LOW.,
> right-moving - the DUT is HIGH
> 
> The hardware only requires 6 ICs plus LEDs and a few passive parts.
> 
> The program is not finished yet. I still have to do some long-term testing and some minor 'tweaking"
> but does what I want.
> 
> It is very interesting to watch an oscillator from a cold start. The lights will race one direction, slow down,
> stop, then race the other direction until it finally slows down and stops.
> 
> M. L. Sproul, W5UGQ
> Amarillo, TX
> msproul at suddenlink.net
> 
> <FreqComp.JPG>