[time-nuts] T-Bolt output harmonics

Charles P. Steinmetz charles_steinmetz at lavabit.com
Sun Aug 12 19:16:30 EDT 2012


Grant wrote:

>I tamed the provided switching power supply noise with some L's and 
>C's, and am now looking at the 10MHz output on a spectrum analyzer. 
>Here is what I measured:
>
>10MHz   +9dbm
>20MHz    -50dbm
>30MHz   -37dbm
>no obvious higher harmonics
>broad noise envelope at 60 > 75MHz @  -60dbm peak
>
>Are these results typical or might I have an adjustment or other problem?

I unhooked my primary Tbolt from the distribution system and ran it 
straight into the 50 ohm input of a SA.  My results:

      10 MHz     +12.66 dBm
      20 MHz     -57.85 dBc
      30 MHz     -59.54 dBc
      40 MHz      below noise floor
      50 MHz     -67.78 dBc

My noise floor was about -80 dBm (~ -90 dBc).  I saw nothing else 
above this floor from DC to 150 MHz except for 60 Hz (at -83 
dBc).  Surprisingly, the power line harmonics were all below the noise floor.

Best regards,

Charles










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