Re: [time-nuts] Noob question on measuring Allan Deviation on 10 MHz source
John, I believe the scaling factor was the key. Thanks. I have v 1.58 of Stable32 and the scaling function now has its own button and is not in the Open dialog. I'm sure I'm nowhere near out of the woods yet, so I'm gonna keep your e-mail addy on speed dial ;-) geo On Wed, Dec 14, 2011 at 4:19 PM, John Ackermann N8UR j...@febo.com wrote: Hi George -- You can feed frequency data into Stable32, but the documentation doesn't clearly explain that you need to scale the readings into fractional frequency using the scaling function in the File/Open dialog. To get fractional frequency, you divide the results by the nominal frequency, except that the scaling model in the Stable32 input box allows multiplication only. So, for a nominal 10 MHz (or 1e7 Hz) source where the data is in Hz format (10,000,000.xxx Hz), you would multiply by 1e-7. But if your counter outputs in MHz format, (10.xxx MHz), that's already effectively scaled by 1e-6. So you end up using 1e-1 as the multiplier. I have lost much hair trying to keep this straight; as wonderful as Stable32 is, the documentation is aimed at people who already know what they are doing. :-) 73, John On 12/14/2011 3:29 PM, George Dubovsky wrote: List; OK, I need to measure the stability of a 10 MHz sine-wave source. After reading a lot of background info on this list and some of the sources that were referenced, I thought I could get away with a frequency measurement. I now think I was wrong. What I have is an Agilent 53230A counter (a pretty capable box - claims 20 ps one-shot resolution in TI mode), a Trimble Thunderbolt, the 10 MHz oscillator to be measured, and a copy of Stable32. My first effort involved feeding the Trimble 10 MHz into the counter as its Ext Reference. I then fed the Trimble 1pps into the Ext Trigger input of the counter and fed the sinewave 10 MHz signal to be measured into Ch 1 of the counter. I then captured the frequency reading of the counter every second and stuffed those numbers into a file. I collected about 20 hours of frequency readings, but when I imported that into Stable32 and attempted to do an Allan Dev plot, it didn't look very good - specifically, the sigma numbers were in the region of 10e-2 to 10e-4. So, I grabbed another Thunderbolt and attempted to do the same measurement on it, figuring that everyone (but me) has taken data on a T'bolt, so I could just look on tvb's site or some such to find proper data on a Tbolt. Again, the plot didn't look like it should. Am I going to have to go to time interval measurements to do what I want? And does this mean I will have to square up my 10 MHz signal to have real edges? geo __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Noob question on measuring Allan Deviation on 10 MHz source
List; OK, I need to measure the stability of a 10 MHz sine-wave source. After reading a lot of background info on this list and some of the sources that were referenced, I thought I could get away with a frequency measurement. I now think I was wrong. What I have is an Agilent 53230A counter (a pretty capable box - claims 20 ps one-shot resolution in TI mode), a Trimble Thunderbolt, the 10 MHz oscillator to be measured, and a copy of Stable32. My first effort involved feeding the Trimble 10 MHz into the counter as its Ext Reference. I then fed the Trimble 1pps into the Ext Trigger input of the counter and fed the sinewave 10 MHz signal to be measured into Ch 1 of the counter. I then captured the frequency reading of the counter every second and stuffed those numbers into a file. I collected about 20 hours of frequency readings, but when I imported that into Stable32 and attempted to do an Allan Dev plot, it didn't look very good - specifically, the sigma numbers were in the region of 10e-2 to 10e-4. So, I grabbed another Thunderbolt and attempted to do the same measurement on it, figuring that everyone (but me) has taken data on a T'bolt, so I could just look on tvb's site or some such to find proper data on a Tbolt. Again, the plot didn't look like it should. Am I going to have to go to time interval measurements to do what I want? And does this mean I will have to square up my 10 MHz signal to have real edges? geo ___ 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.
Re: [time-nuts] Noob question on measuring Allan Deviation on 10 MHz source
Once you get the frequencies matched with a fraction of 1 Hz, I would measure the phase between the 10 MHz source and the 10 MHz from the Trimble. On 12/14/2011 12:29 PM, George Dubovsky wrote: List; OK, I need to measure the stability of a 10 MHz sine-wave source. After reading a lot of background info on this list and some of the sources that were referenced, I thought I could get away with a frequency measurement. I now think I was wrong. What I have is an Agilent 53230A counter (a pretty capable box - claims 20 ps one-shot resolution in TI mode), a Trimble Thunderbolt, the 10 MHz oscillator to be measured, and a copy of Stable32. My first effort involved feeding the Trimble 10 MHz into the counter as its Ext Reference. I then fed the Trimble 1pps into the Ext Trigger input of the counter and fed the sinewave 10 MHz signal to be measured into Ch 1 of the counter. I then captured the frequency reading of the counter every second and stuffed those numbers into a file. I collected about 20 hours of frequency readings, but when I imported that into Stable32 and attempted to do an Allan Dev plot, it didn't look very good - specifically, the sigma numbers were in the region of 10e-2 to 10e-4. So, I grabbed another Thunderbolt and attempted to do the same measurement on it, figuring that everyone (but me) has taken data on a T'bolt, so I could just look on tvb's site or some such to find proper data on a Tbolt. Again, the plot didn't look like it should. Am I going to have to go to time interval measurements to do what I want? And does this mean I will have to square up my 10 MHz signal to have real edges? geo ___ 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. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ 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.
Re: [time-nuts] Noob question on measuring Allan Deviation on 10 MHz source
Hi George -- You can feed frequency data into Stable32, but the documentation doesn't clearly explain that you need to scale the readings into fractional frequency using the scaling function in the File/Open dialog. To get fractional frequency, you divide the results by the nominal frequency, except that the scaling model in the Stable32 input box allows multiplication only. So, for a nominal 10 MHz (or 1e7 Hz) source where the data is in Hz format (10,000,000.xxx Hz), you would multiply by 1e-7. But if your counter outputs in MHz format, (10.xxx MHz), that's already effectively scaled by 1e-6. So you end up using 1e-1 as the multiplier. I have lost much hair trying to keep this straight; as wonderful as Stable32 is, the documentation is aimed at people who already know what they are doing. :-) 73, John On 12/14/2011 3:29 PM, George Dubovsky wrote: List; OK, I need to measure the stability of a 10 MHz sine-wave source. After reading a lot of background info on this list and some of the sources that were referenced, I thought I could get away with a frequency measurement. I now think I was wrong. What I have is an Agilent 53230A counter (a pretty capable box - claims 20 ps one-shot resolution in TI mode), a Trimble Thunderbolt, the 10 MHz oscillator to be measured, and a copy of Stable32. My first effort involved feeding the Trimble 10 MHz into the counter as its Ext Reference. I then fed the Trimble 1pps into the Ext Trigger input of the counter and fed the sinewave 10 MHz signal to be measured into Ch 1 of the counter. I then captured the frequency reading of the counter every second and stuffed those numbers into a file. I collected about 20 hours of frequency readings, but when I imported that into Stable32 and attempted to do an Allan Dev plot, it didn't look very good - specifically, the sigma numbers were in the region of 10e-2 to 10e-4. So, I grabbed another Thunderbolt and attempted to do the same measurement on it, figuring that everyone (but me) has taken data on a T'bolt, so I could just look on tvb's site or some such to find proper data on a Tbolt. Again, the plot didn't look like it should. Am I going to have to go to time interval measurements to do what I want? And does this mean I will have to square up my 10 MHz signal to have real edges? geo ___ 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.
