On Sunday 11 June 2006 00:00, KD5NWA wrote: > Huff&Puff encompasses a lot of circuit variations, I like to use the > more advanced forms that look at more than one bit of variation. The > simpler versions have the problem that the circuit is never happy and > keeps toggling back and forth not happy with either choice of frequency. > > The version I like is basically a PLL circuit but the phase > comparator locks to any multiple of the reference frequency not at an > exact one and only one frequency. The phase comparator is the only > difference between it and a PLL. It tends to be smooth like a PLL in > that it's not hunting for the frequency all the time like the one bit H&P > do.
Huff and Puff _stabilisers_ implement a frequency-locked-loop, not a phase-locked loop... I suggest that in 2006 it's a pretty crazy choice of circuit topology, although it was an interesting diversion in the 1970s. FWIW, I'm not that keen on DDS LOs either, but it's too late at night here to write the several hundred words that would be needed to explain why. The microwave SDR group <http://uwsdr.berlios.de> of which I'm a member, is working on the application of fractional-N synthesis, and there are topologies which could be applied to HF. Consider a microwave frac-N synthesiser divided down to HF in an LMX2326, f'rinstance. Vy 73 Chris GW4DGU ------------------------ Yahoo! Groups Sponsor --------------------~--> Get to your groups with one click. Know instantly when new email arrives http://us.click.yahoo.com/.7bhrC/MGxNAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> 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/
