On Wed, 4 Oct 2017 12:02:35 +1300 (NZDT) Bruce Griffiths <bruce.griffi...@xtra.co.nz> wrote:
> I could measure the PN of the TAPR variant of the Wenzel circuit > as well as the PN of the comparator based circuit (with CMOS output buffer). BTW: one thing that has been bothering me with the TAPR variant of the Wenzel circuit is the 100µH inductor in the tail of the diff-pair. As it presents an impedance of approximately 6k at 10MHz it is cruical to the working of the diff-pair (which would otherwise be just two independent transistors). But I was unable to find a 100µH inductor with a self-resonance frequency significantly higher than 10MHz. Quite to the contrary, most seem to mingle around 1MHz. This poses two questions: 1) does the TADD2 mini use a special inductor? and 2) Given the 100µH inductor has an SFR somewhere in the range of 1-5MHz and is likely to have significant core losses around and/or above 10MHz, doesn't this limit the performance of the circuit quite significantly? I have been thinking of replacing the inductor with a current source (simple current mirror) and at least in the spice simulations it looks decent. No idea of the noise performance, though. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson _______________________________________________ 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.