I was pretty sure that the 4000 CMOS range was only really good sub 1Mhz I am wrong here? please correct me thats why I chose the 74HC series as its high speed CMOS??
On Mon, Nov 28, 2011 at 6:58 PM, ehydra <[email protected]> wrote: > Maybe the HC04 oscillates but the experimenter doesn't see it. Or > misunderstood that ICs have to be seen from top, not bottom like > transistors. > > It is better to use an HCU04. Even a 4069UB should work at 8MHz@5V. I would > prefer 100K feedback and several stages AC-coupled. > > The 5V is nominal, so use 5V not 4,9V. But it is not important for your > problem. > > - Henry > > > Attila Kinali schrieb: >> >> On Mon, 28 Nov 2011 16:15:37 +1100 >> Michael Malloy <[email protected]> wrote: >> >>> Hi all I ordered a 8.192MHZ TCXO 1.0PPM >>> Now it was supposed to have a clipped sine wave output? however it >>> looks more like a saw tooth, I assumed a clipped sine would be a sine >>> wave with the peaks clipped, I am running this through >>> a 150pF cap and then using a inverter amplifier i.e. 74HC04 with a 1M >>> resistor from input to output. >>> >>> am I over loading or loading down the the oscillator, or should I be >>> changing the buffer capacitor? >>> I mean the circuit is working but its not 45/55 duty cycle >>> the out put looks like the first 0 -90 degrees of a sine wave then >>> drops to zero stays there for about 20% of the duty cycle then ramps >>> back up? >> >> Do you measure the TCXO raw, w/o any circuitry attached? >> Because this sounds rather like that the 74ZHC04 is messing >> with the signal. Maybe the 1M resistor isnt really 1M? >> >> Other than that, i would feed the output directly to >> a 74HC14 (schmitt trigger input) to square it. If you >> want to have precise or adjustable duty cycle, you can also >> use a comparator (but make sure to include enough hysteresis, >> otherwise the comparator might oscillate) >> >> >> Attila Kinali >> > > -- > ehydra.dyndns.info > > _______________________________________________ > 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. > -- #include <sig.h> /* ================ */ Michael /*How crazy does it get on the moon, when theres a full Earth?*/ _______________________________________________ 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.
