[time-nuts] Re: PLL subharmonic spurs

[glen english LIST]

alright then I'll have another go at a more useful response, and I will 
provide a reference

Try Floyd Gardiner's  book , "Phaselock Techniques". I have the 3rd 
edition in my hand, There is a whole chaptor on phase detectors Chapter 
10.  ISBN 978-0-471-43063-6

There is an excellent section on the effect of the PD s-curve on 
different applications.

The waveforms input to the phase detector should be tailored to the 
particular phase detector in use.

The needs of the phase comparator really are dictated by the needs of 
the application- PLL or FLL or both . Sensitivity to harmonics may 
actually be desirable... long live the XOR gate !

Example - Harmonic phase (all of them)Â Â Â  may influence a phase 
comparator with wide bandwidth much more than one with narrow bandwidth. 
- but this may only generate a fixed phase error and this may not bother 
a frequency locked loop.

A double balanced mixer with pure sine wave sources is probably the gold 
standard

Horses for courses



On 7/02/2022 9:03 pm, mail at vresearch.pt wrote:
> Just being rude Glen.
>
> I'm searching for a source document that someone could share. Just that.
>
> -----Original Message-----
> From: glen english LIST <glenlist at cortexrf.com.au>
> Sent: 6 de fevereiro de 2022 22:51
> To: time-nuts at lists.febo.com
> Subject: [time-nuts] Re: PLL subharmonic spurs
>
> This sounds a little off-topic.
>
> If you are interested in harmonics of the reference frequency at the input
> to the phase detector, this will be entirely defined by the fourier series
> of the source. Get yourself a 2nd year EE student, they'll have this info
> for you.
>
> There will also be harmonics and products generated by the phase detector
> inputs, perhaps, since logic gates have to square up rounded inputs.
>
> depends what sort of phase detector all the way from full linear multiplier
> to an XOR gate !
>
>
> glen
>
>
> On 7/02/2022 9:27 am, mail at vresearch.pt wrote:
>> I'm really interested to estimate are multiple of the reference frequency
> (i.e. at the input of phase detector).
>
-- 
Glen English
RF Communications and Electronics Engineer

CORTEX RF

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