Moin John, Yes, I know I am comming back to an "old" discussion, but I have questions that need to be answered! :-)
On Wed, 06 May 2015 08:56:10 -0400 John Ackermann N8UR <[email protected]> wrote: > Wenzel has published the schematic of an excellent squaring circuit. I > don't have the URL for their version handy, but I used it (with a couple > of mods) in the TADD-2 and TADD-2 Mini designs. You can see the > schematic in the T2-Mini users guide at > http://www.tapr.org/~n8ur/T2_Mini_Manual.pdf. The manual says: ---schnipp--- The purpose of the input circuit is to convert the RF input signal into a low-jitter square wave that can drive the PIC clock input. The circuit is closely based on the one published by Wenzel at http://www.wenzel.com/documents/waveform.html, with modifications suggested by Bruce Griffiths and Ulrich Bangert. The revised circuit works with inputs as low as -20dBm. ---schnapp--- The modification I can see is that the "current source" part of the differential pair changed from being a single, shared resistor of 100R to an inductor of 100uH, then splits up into two resistors of 220R, which are bridged by a 100nF capacitor. The inductor results in a reactance between 62R (100kHz) and 12k (20MHz) for the input range. Can you shed a bit of light on why you did those modifications and what the intended effect is? 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 -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
