> Von: Magnus Lindahl <sm4...@telia.com> > Do you have schematics, PCB-design etc. to share on your design with 3* > BF862?
I will publish the results in Dubus. (www.dubus.org) board size is 1.5 * 2.5 inch for oscillator, buffer, reference conditioner and PLL. No soldering without a microscope, however. Lots of SSOP16, sot-336, 0603 & friends. I wanted to make a VHF crystal oscillator that could be locked to a 10 MHz reference and be used for the usual transverter designs. That required a locking grid of 333 or 500 KHz. Furthermore, I wanted to avoid microcontrollers and other stuff that had to be programmed. I wanted just normal stuff from Digi-Key and your favorite crystal supplier. (Also, I wanted a nice clock source for state-of-the-Art 16 bit ADCs) The fine locking grid has a devastating influence on the design. Either one compares at 500 KHz, then locking to small error will take months, the pull-in range is ridiculous (I don't want an oven for the 100MHz) ---- or one compares to a harmonic of the 500 KHz, then the phase comparator gain is ridiculous and the PLL kills the 100 MHz phase noise. Probably I'll give in and stay with a 10 MHz grid. That will help hams who want to multiply to 100 GHz and above. I now have limited access to an Agilent signal source analyzer that does the three cornered hat thing with cross correlation to 2 precision oscillators close to real time. I'm still stuck at -135 dB@ 100Hz @100 MHz, but without Rohde's limiter. (only antiparallel Schottky across tank circuit and with BFG196 emitter follower) I'll test w/o the follower and with the new limiter in week 1/2010 There are many things still to explore: thin film vs thick film resistors, influence of emitter/source resistors, amplitude clamps, crystals, ....... regards, Gerhard DK4XP U.L.Rohde/David P. Newkirk: RF/Microwave Circuit Design For Wireless Applications, page 762++ Wiley, ISBN 0-471-29818-2 _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
