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.
