[time-nuts] TEC party: hardware suggestion

Chris Albertson albertson.chris at gmail.com
Fri Jul 1 18:44:26 UTC 2011


Posted to this list just minutes before is a live on-line measurement
demo.  The hardware used is pretty simple.  Just four inexpensive
parts (and a computer)
http://websdr.ewi.utwente.nl:8901/lichtnet/

On Fri, Jul 1, 2011 at 10:08 AM, Tom Holmes <tholmes at woh.rr.com> wrote:
> In thinking about how to implement a scheme to make the phase and frequency
> comparison using what I have on hand, I considered the following as a
> possibility:
>
> An ARB with a GPS derived 10 MHz reference set to 60 Hz. The one I have has
> a very low jitter spec. It actually is a dual ARB so I could use the 2nd
> independent channel to calibrate the phase detector
>
> A phase comparator, which I would have to construct or buy. The phase
> difference output would be a DC voltage that could be calibrated. This is
> the only piece that I know little about so suggestions on how to create this
> would be appreciated. A 2-channel digital scope? A simple IC comparator?
> Hey, it's only 60 Hz, how tough could it be?
>
> A 6-1/2 digit DMM that could either be polled at intervals of a few mSec, or
> could be set to capture a number of readings for transfer to the PC. In
> either case the data could be time-stamped.
>
> Sounds like fun!
>
> Tom Holmes, N8ZM
> Tipp City, OH
> EM79
>
>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Chris Albertson
>> Sent: Thursday, June 30, 2011 12:28 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] TEC party: hardware suggestion
>>
>> On Thu, Jun 30, 2011 at 1:38 AM, Achim Vollhardt <avollhar at physik.uzh.ch>
>> wrote:
>> > Time-Nutties,
>> >
>> > how about using a small uC (PIC/AVR) clocked with 100ns instruction
> speed.
>> > Start = 1PPS from GPS, Stop = 60 Hz Edge? Use internal capture hardware
> to
>> > count processor cycles in between.
>>
>> Recently posted plots show that all you need is an AC wall wart
>> transformer and two resistors.   a uC is total overkill
>>
>> The xformer and resistor voltage divider works because by dumb luck
>> the pin in the rs232 port was designed to accept a signal that looks a
>> lot like low voltage AC and even better, already has edge detection
>> built in.  Also by dumb luck someone already wrote the software to
>> monitor the pin's status and time stamp transitions.     This really
>> is a case of pure luck.
>>
>>
>> --
>>
>> Chris Albertson
>> Redondo Beach, California
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California



More information about the time-nuts mailing list