[time-nuts] Low phase noise VCO

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Feb 9 20:32:34 EST 2010


Thats not very useful when you want the 4th harmonic as its amplitude is 
zero fro a 25% duty cycle.
Using a duty cycle of 1/8, 3/8 or 5/8 will maximise the amplitude of the 
4th harmonic.

see:
http://www.wenzel.com/pdffiles1/pdfs/choose.pdf

Bruce

Max Robinson wrote:
> If you start with a square wave odd order is all you can get but if 
> you start with a pulse with a 25% duty cycle you can get even order.  
> It's best to optimize the pulse width for the harmonic you want.
>
> Regards.
>
> Max.  K 4 O D S.
>
> Email: max at maxsmusicplace.com
>
> Transistor site http://www.funwithtransistors.net
> Vacuum tube site: http://www.funwithtubes.net
> Music site: http://www.maxsmusicplace.com
>
> To subscribe to the fun with transistors group send an email to.
> funwithtransistors-subscribe at yahoogroups.com
>
> To subscribe to the fun with tubes group send an email to,
> funwithtubes-subscribe at yahoogroups.com
>
> ----- Original Message ----- From: "Nick Foster" <bistromat at hotmail.com>
> To: <time-nuts at febo.com>
> Sent: Tuesday, February 09, 2010 6:35 PM
> Subject: Re: [time-nuts] Low phase noise VCO
>
>
>>
>>> From: bill at iaxs.net
>>> To: time-nuts at febo.com
>>> Date: Tue, 9 Feb 2010 18:24:39 -0600
>>> Subject: Re: [time-nuts] Low phase noise VCO
>>>
>>> Which leads me to ask a novice question:
>>>
>>> Why not pull a 16 MHz crystal and multiply to 64 MHz?
>>>
>>> If you count down from 64 to 10 MHz, isn't the multiplication inside 
>>> the
>>> PLL?
>>>
>>> Perhaps the noise is multiplied by 4, but would it work for the 
>>> intended
>>> purpose?
>>>
>>> Bill Hawkins
>>
>> Can you do x4 multipliers? I thought odd-order harmonics were usually 
>> used for multipliers. I'd be happy to be wrong!
>>
>> Nick
>>






More information about the time-nuts mailing list