[time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.

Magnus Danielson magnus at rubidium.se
Sun Sep 18 08:01:39 EDT 2016


Peter,

Take a peak here (scroll down to the graphs):
http://dsp.stackexchange.com/questions/5959/add-odd-even-harmonics-to-signal

The full-wave rectifier creates a symmetric distortion, which causes 
even harmonics. Each half-cycle has the same output structure, so the 
resulting signal has twice the frequency of the input. The sawtooth 
slope as the capacitor discharge has in itself both even and odd 
overtones, creating the end result of 100 Hz, 200 Hz, 300 Hz etc.
We can expect leakage of the 50 Hz and some harmonics on that, due to 
inbalance between diodes and other paths.

Cheers,
Magnus

On 09/18/2016 01:11 PM, Peter Marczinowski wrote:
> Even harmonics are caused by asymmetrical nonlinearities, odd harmonics
> by symmetrical nonlinearities.
>
> Peter
>
>
> Am Sonntag, 18. September 2016 schrieb Magnus Danielson :
>
>     Hi,
>
>     On 09/18/2016 12:26 PM, David C. Partridge wrote:
>
>         The local power is 50Hz, so I can understand the 100Hz spurs,
>         but I don't
>         quite "get" where the 200Hz spurs are coming from.  Or is that
>         just BAU
>         harmonics?
>
>
>     Consider full-wave rectification of 50 Hz, the power consumption
>     load on the capacitor after the rectifier creates an inverse
>     sawtooth wave of 100 Hz, and sawtooth waveshape have both even and
>     odd harmonics.
>
>     While much of this is regulated out in the next step, some of it
>     makes it though.
>
>     Cheers,
>     Magnus
>
>
>
>         Thanks
>
>         Dave
>
>
>
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