[time-nuts] 10 MHz Band-Pass Filter Needed (Roberto Barrios)

Bruce Griffiths bruce.griffiths at xtra.co.nz
Thu Jan 8 22:58:11 UTC 2009


Roberto Barrios wrote:
>> The GPSDO I want to use has an output rich in harmonics. In some> cases that is good, but Murphy rules and in the application I have> today, it is not good.> > I need a 10 MHz Band-Pass Filter, Bandwidth is not critical, something> small with SMA connectors would be ideal, but I can live with BNC.> > Anyone have such a beast or know where I can get one ? I checked Mini-Circuits> and choked on the price !!> > Thanks, Dick, W1KSZ> 
>>     
> Hi Dick,
>  
> There are plans for a simple nine section low pass filter here:
> http://jwmeng.com/AppNote/AppNote003.html
>  
> You can also use (I did) a filter from an old 10mbit ethernet network card, as suggested here:
> http://www.uhf-satcom.com/misc/10MHz_dist/
>  
> I joined this list just yesterday, so hello to everyone. I live in Madrid and I'm interested in frequency measurement for HAM purposes. Not understanding most of the things you guys discuss here, I thought I would never have the opportunity to give my 2 cents... I´m currently working on a simple GPSDO that (luckily) some  of you may find interesting. I'll send you details in a few days so I can get your opinions and (hopefully) it inspires/helps someone.
>  
> Bests Regards & 73's
> Roberto Barrios, EB4EQA
> Madrid, Spain
>  
>
>   
Roberto

But what is the filter phase shift tempco?
In the presence of temperature changes the filter phase shift variation
is equivalent to phase and frequency modulation of the output of the filter.
One cure is to use low tempco filter parts and place the filter in an oven.

Bruce




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