[time-nuts] Ultra High Stability Time Base Options for 53132A

[Bob Camp]

Hi

I suspect that the “more alarming” signatures on the stable sources are a function of them 
“holding still” (in phase) longer. With the less stable sources, the junk is still there, it
just is smeared out more.

Bob

> On Apr 22, 2015, at 6:17 AM, Hans Holzach <hans.holzach at gmail.com> wrote:
> 
> during the last days i ran a few tests with different high stability options.
> 
> setup:
> channel 1: thunderbolt 10 mhz divided down to 1 pps
> channel 2: trimble 73090 DOCXO 10 MHz divided down to 1 pps. frequency offset about 7e-9
> internal time bases: no additional time base; morion mv89a; trimble 34310-t
> external time bases: no external time base; thunderbolt 10 mhz
> tapr distribution amplifier, tapr frequency dividers
> 
> strong temperature swings in the attic, about 10°C, thunderbolt not protected, trimble 73090 (channel 2) in box with a lot of small water containers.
> 
> internal time base: NO high stability time base, external time base: NONE
> adev: https://farm9.staticflickr.com/8742/17196609681_53937b7e5d_b.jpg
> spectral density: https://farm8.staticflickr.com/7688/17197584451_50e359e46f_b.jpg
> 
> internal time base: NO high stability time base, external time base: thunderbolt 10 mhz
> adev: https://farm8.staticflickr.com/7587/16997478560_1a422eb0f2_b.jpg
> spectral density: https://farm8.staticflickr.com/7604/17159258816_743ba1f83a_b.jpg
> 
> 
> internal time base: morion mv89a, external time base: NONE
> adev: https://farm9.staticflickr.com/8802/16962399320_908fea406c_b.jpg
> spectral density: https://farm6.staticflickr.com/5349/16565001513_e3f47482e6_b.jpg
> 
> internal time base: morion mv89a, external time base: thunderbolt 10 mhz
> adev: https://farm9.staticflickr.com/8774/16949313140_29937eb5d6_b.jpg
> spectral density: https://farm6.staticflickr.com/5346/17159259246_eb20993753_b.jpg
> 
> 
> internal time base: trimble 34310-t, external time base: NONE
> adev: https://farm9.staticflickr.com/8816/17232552925_4f4e9bc267_b.jpg
> spectral density: https://farm8.staticflickr.com/7644/17044785268_bdb5b2fa97_b.jpg
> 
> internal time base: trimble 34310-t, external time base: thunderbolt 10 mhz
> adev: https://farm9.staticflickr.com/8784/16602405264_41fefbed43_b.jpg
> spectral density: https://farm9.staticflickr.com/8710/16604641953_de800d9769_b.jpg
> 
> 
> more plots (phase and autocorrelation samples) at: https://www.flickr.com/photos/olmstead/collections/72157651929343312/
> 
> looking at the ps plots: it seems to be a good idea not to use a high stability time base if an external time base like a thunderbolt is plugged to the counter. both external and internal time bases seem to add a lot of spurs to the power spectrum, at least in my setup with my gear. ugliest combination is a morion high stability time base AND an external time base.
> 
> best regards,
> hans
> _______________________________________________
> 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.