Dr Bruce Griffiths wrote: > Magnus Danielson wrote: > >> Hi! >> >> I have a HP G-69B-2 Z-235 Crystal Oven 100 kHz lying around. I'm considering >> heating it up and run it (just for fun). Operating temperature is 65 C. >> >> Anyone care to share any information on this device? I have no clue which box >> it ever was in or anything. Also, thoughts of suitable oscillator setups? >> >> I should probably have a run-by the network analyzer. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list >> time-nuts@febo.com >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >> > Magnus > > Presuming you just have a crystal in an oven, the simplest low phase > noise oscillator setup is probably the following: > http://www.wenzel.com/pdffiles/xtalosc.pdf > > However you will need to have some idea of the desired crystal current. > > Bruce > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Magnus
To avoid a dc voltage across the crystal a capacitor in series with the crystal and a high value (100M or more at 100KHz) shunt resistor across it may be desirable. Recent extensions to Leeson's theory of oscillator phase noise indicate that using an oscillator active device that is off for most of the oscillator cycle can be advantageous in reducing the phase noise. With a Colpitts crystal oscillator the optimum value of C2/C1 is around 4 as confirmed by experiment. Application of this theory by Intel and others has lead to a significant reduction of CMOS ring oscillator phase noise. This theory also accurately predicts the 1/f phase noise corner frequency from the 1/f noise corner frequency of the oscillator active devices. The 1/f phase noise corner frequency is not necessarily identical to the device 1/f noise corner of the device. Bruce _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
