Hallo Cecil, I wrote originally some notes about pll's because I was asked to do so. It is a very simple and maybe basic type of information, I gave.
Now, I would like to hear from You the "other side of the world", which advantages are to await from a digitial system? Would You like to send some lines about the essential parts and give an explanation about the main topics? Wolfgang --- In [email protected], KD5NWA <[EMAIL PROTECTED]> wrote: > > You are thinking in terms of analog mixers, Digital QSD mixers are a > whole other world. QSD mixers have to have a square wave clock, and > function way better than a analog mixer if given a low phase noise > "digital" clock. If they are given an analog sine wave for a clock, > you would have to turn that back into a digital signal which can > introduce jitter, so when possible it's best to keep the clock > digital as much as possible. In a well designed QSD system a clock > divider will improve the phase noise figures not make it worse. > > > Food for thought. > > > At 04:03 PM 4/8/2006, you wrote: > >An addendum to my info: > > > > From this paper, I gave You the internet-adress, You can clearly see > >and take some consequences for receiver constructing. > > > >1.1. If one has an oscillator with phase-noise, You not only mix the > >oscillator not only with the incoming frequency, but also with the > >phase-noise of the oscilltor. It is something like a synchronous > >mixing with a lot of frequencies and a lot of mixing products. The > >less the bandwidth of the phase-noise the better for quality of mixing > >result. > > > >1.2. At mixing You mix a strong signal (the oscillator-signal) with a > >very little one, the incoming signal. Partly You have to filter the > >product. > > > >1.3. You should avoid all solutions with phase noise inclusive > >solutions with ic-dividers. > > > >1.4. The better the signal of the mixing process, the better the > >result. Because of that, to gain ultimate quality, You should forget a > >lot of solutions and change to a dds-circuit with a very high > >working-frequency. All other solutions have a lack of quality, to > >reach ultimate success. > > > >1.5. The alternative could be a quartz-osciallator, but one is not > >able to change the frequency in a wider range. > > > >1.6. My "feeling is" even concepts with I,Q-solutions could be better, > >if a fast dds-circuit is used. > > > >1.7. Having a rectangular signal meens a lot of filtering.... and a > >lot of useless noise. > > > >One can see, that using a fast dds-circuit is at the moment even for > >traditional receveiver concepts in let me say AM, SSB and other > >modulation-types is "state of the art" and You miss-use time and > >effort for other versions. > > > >I will look for answers coming. In the meantime, I will work with my DRT1. > > > >An incoming signal is always not a digital one even, if its > >constructed digital by modulation as DRM. > > > >Wolfgang > > > >--- In [email protected], "Wolfgang Hartmann" > ><dadalbinder@> wrote: > > > > > > Hallo to all, especially to Dan. > > > > > > Here is an email adress, wher You can find some informations in german > > > language. > > > > > > http://www.elexs.de/clock3.htm > > > > > > You see the phase-noise and the noise carpet of several designs. > > > > > > They have a lot more on DRM, Elektor-receiver. > > > > > > Wolfgang > > > > > > > > > > > > > > > > > > > > > > > > >Yahoo! Groups Links > > > > > > > > > > > Cecil Bayona > KD5NWA > www.qrpradio.com > > "Windows the worlds most successful software virus" > 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/
