Hi Edgardo -- Sorry, I should have explained. Tau0 is shorthand for the "base" tau -- the actual interval between each measurement. You can measure longer tau by simply using every nth measurement. So tau0 = 1 second simply means you're taking a reading once per second.
John On Nov 20, 2012, at 2:29 AM, Edgardo Molina <xe1...@amsat.org> wrote: > Dear John Ackermann, > > I find your reply to my request to be very interesting. Without fear of > asking. May I know how do I achieve a Tau 0 measurement in a 1 second > interval with my setup? (HP-53132A + TimeLab). > > Please tell me if I am wrong. I assume I would take the 10 MHz output from > the 53132A and plug it into the Channel 1 input, while the external reference > of 10 MHz is disconnected. > > As far as I am concerned, TimeLab does not allow a value of 0 for Tau. If I > enter zero as the measurement time duration I get an error and actual > acceptable Tau range. The smaller value is in the order of 1E-6s. Am I > getting it right? I am sorry for my confusion. > > Regards, > > > > Edgardo Molina > Dirección IPTEL > > www.iptel.net.mx > > T : 55 55 55202444 > M : 04455 10045822 > > Piensa en Bits SA de CV > > > > Información anexa: > > > > > CONFIDENCIALIDAD DE INFORMACION > > Este mensaje tiene carácter confidencial. Si usted no es el destinarario de > este mensaje, le suplicamos se lo notifique al remitente mediante un correo > electrónico y que borre el presente mensaje y sus anexos de su computadora > sin retener una copia de los mismos. Queda estrictamente prohibido copiar > este mensaje o hacer usode el para cualquier propósito o divulgar su en forma > parcial o total su contenido. Gracias. > > > NON-DISCLOSURE OF INFORMATION > > This email is strictly confidential and may also be privileged. If you are > not the intended recipient please immediately advise the sender by replying > to this e-mail and then deleting the message and its attachments from your > computer without keeping a copy. It is strictly forbidden to copy it or use > it for any purpose or disclose its contents to any third party. Thank you. > > > > > > > On Nov 14, 2012, at 8:13 PM, John Ackermann N8UR <j...@febo.com> wrote: > >> Edgardo, the minimum sample rate in practice is determined by the noise >> floor of the measurement system. I would suggest that you do a baseline >> test by measuring the counter reference against itself with a tau0 (sample >> rate) of 1 second. You'll see a best-case result and from it you can >> determine at which sample rate your noise floor is better than the predicted >> performance of the oscillator under test. You'll probably find that you are >> measurement-noise limited below several hundred seconds. >> >> Also, you'll generally get a lower noise floor doing time interval rather >> than frequency measurements, so you might experiment with that, which >> normally involves using a low-rate signal such as PPS for "start" and "stop" >> channels. >> >> John >> >> On Nov 14, 2012, at 8:43 PM, Edgardo Molina <xe1...@amsat.org> wrote: >> >>> Dear Group, >>> >>> Now that I have setup TimeLab along with the Prologix GPIB to USB adapter >>> and the HP-53132A frecuency counter, I am starting to get some data from my >>> frequency standards. Still I think I have a long way to go in front of me. >>> >>> One of the main concerns that cross my mind at this point are: >>> >>> a. What is the recommended sampling duration to consider for Quartz, >>> Rubidium and other types of oscillators? >>> b. What are the recommended sampling intervals for the above mentioned >>> oscillator types? >>> c. I am using a 10 MHz Rb FE-5806A frequency standard as an external >>> reference for the HP-53132A. >>> d. I am connecting my DUT at the frequency counter channel 1 >>> e. I am setting Timelab for Data Type = Frequency >>> f. My graphs somehow have the same geometry of classical ADEV examples, I >>> can differentiate the ADEV noise types quite easily. >>> g. Should I use sub-second sampling intervals for my graphs to start closer >>> to the vertical axis of the graph? Or should I use a conservative 1s >>> sampling rate? >>> >>> With the previous questions I am looking for consistency in my ADEV >>> studies. Are there any typical ADEV conditions to be considered when >>> analysing this way? >>> Am I missing something? My apologies to everybody if I am missing something >>> or doing it the wrong way. In the end I want to learn more than anything >>> else. >>> >>> Your kind comments are welcome. Thank you. >>> >>> Best regards, >>> >>> >>> >>> Edgardo Molina >>> Dirección IPTEL >>> >>> www.iptel.net.mx >>> >>> T : 55 55 55202444 >>> M : 04455 10045822 >>> >>> Piensa en Bits SA de CV >>> >>> >>> >>> Información anexa: >>> >>> >>> >>> >>> CONFIDENCIALIDAD DE INFORMACION >>> >>> Este mensaje tiene carácter confidencial. Si usted no es el destinarario de >>> este mensaje, le suplicamos se lo notifique al remitente mediante un correo >>> electrónico y que borre el presente mensaje y sus anexos de su computadora >>> sin retener una copia de los mismos. Queda estrictamente prohibido copiar >>> este mensaje o hacer usode el para cualquier propósito o divulgar su en >>> forma parcial o total su contenido. Gracias. >>> >>> >>> NON-DISCLOSURE OF INFORMATION >>> >>> This email is strictly confidential and may also be privileged. If you are >>> not the intended recipient please immediately advise the sender by replying >>> to this e-mail and then deleting the message and its attachments from your >>> computer without keeping a copy. It is strictly forbidden to copy it or use >>> it for any purpose or disclose its contents to any third party. Thank you. >>> >>> >>> >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@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@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@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
