[time-nuts] Query: Interest in clock synthesizer module -- useful for stabilizing PC timekeeping (among other things)
John Ackermann N8UR
jra at febo.com
Wed Aug 16 21:13:45 UTC 2006
Poul-Henning Kamp wrote:
> In message <44E384D2.7020609 at febo.com>, John Ackermann N8UR writes:
>
>> There's information about my prototype (and a picture) at
>> http://www.febo.com/time-freq/hardware/ICS525/
>
> Running at 200MHz, the third harmonic at 600MHz is only
> down -11.5dB, while the 5th harmonic at 1GHz is down -20dB.
> With a 20MHz output, the 3rd harmonic is -10dB and you have
> to get to the 23rd harmonic at 460MHz before you hit -30dB.
>
> Uhm, this is actually a good thing. The thing is supposed to have
> a square-wave output, so all the odd-numbered harmonics have better
> be there and have better follow the 1/N amplitude law...
Yeah, I remember now that I was going to update the web page to make it
clear that you'd sort of expect lots of odd harmonics from a square
wave. I'll try to do that tonight.
John
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