That's the max frequency of the divider circuits, the phase comparator works at a much much lower frequency after division of both the reference and the VCO ...
What we are looking at is a 1 to 1 phase comparison (no divders) up to 50-60Mhz ... for example set the DDS at 30 mhz and the VCO tracks at 30Mhz so the phase comparator works for both signals at 30 Mhz JR --- In [email protected], F6EHJ <[EMAIL PROTECTED]> wrote: > > Hi JR, > > Look at the MC145170, 185 MHz is the upper limit with 500mV at its input. > Not too much easy to speak with it... > > Best regards, > > Gérard/F6EHJ > > jr_dakota a écrit : > > >Given the State of the Art, 50Mhz phase detectors are probably > >possible fairly easily.... > > > >Problem is everything commercial is geared for 900Mhz cellphones, > >gigahertz broadband wireless, etc and it's not possible at those > >frequencies (yet) for 1 on 1 phase comparison. The 50Mhz and under > >market is way too small to make anyone want to develop such an IC ... > > > >JR > > > >--- In [email protected], "sis108" <[EMAIL PROTECTED]> wrote: > > > > > >>I often wondered why you couldn't use a 1x VCO and phase detctor. > >> > >>IE DDS 50-60Mhz out VCO 50-60MHZ both phase detectors 50-60mhz in. > >>Hopefully the loop filter would kill the spurs. > >> > >>I have not found high speed phase/freq detectors however. > >> > >>Anyone have an opinion on how well this might work to kill the spurs? > >> > >> > >>--- In [email protected], KY1K <[EMAIL PROTECTED]> wrote: > >> > >> > >>>Has any amateur ever done a DDS in conjunction with a PLL to clean up > >>>spurs? I hear chatter about it working well if the PLL is designed > >>>properly, but have never run across any real life examples of the 2 > >>>technologies rolled into one. > >>> > >>>I understand the DDS has advantages, especially in it's ability to > >>>change frequency quickly. But, if rapid qsy's are not needed, I would > >>>think a PLL with a slow response time in the filter would be as good > >>>or better with respect to spectral purity than any DDS available > >>> > >>> > >today. > > > > > >>>Appreciate any pointers to web resources discussing this topic. > >>> > >>>Thanks, > >>> > >>> > >>>Art > >>> > >>> > >>> > > > > > > > > > > > > > > > > > >Yahoo! Groups Links > > > > > > > > > > > > > > > >--------------------------------------------------------------------------------------- > >Wanadoo vous informe que cet e-mail a ete controle par l'anti-virus mail. > >Aucun virus connu a ce jour par nos services n'a ete detecte. > > > > > > > > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
