Some further comments...

Most oscillators that use a single active device (transistor or tube) are
linear analog circuits. You are trying to use a nonlinear (that is,
digital) device in an analog application.

The circuit using two inverting gates chasing each other's tail is called a
ring oscillator. It can be made to work without a crystal but will be
relatively unstable. Most such circuits I have seen using a crystal are in
non ciritical applications. I suspect that it will be not too stable
(temperature wise) and may not be suitable for use in a radio circuit.
Also, you will need to use a good filter becasue the signal will be full of
harmonics.

Jim
N8EE

"PaoloC" wrote in message
...
[Slightly off-topic request]

Hi.
As of the other post of mine, another part of my weekend was spent
trying to get a XOR gate to oscillate with a XTAL.

I have a working 74HC14 oscillator:
"One gate of a 74HC14. 470ohm resistor from gate output to the parallel
of 1Mohm//XTAL. 10pF and 33pF (from the junkbox) capacitors to ground on
each side of the XTAL."

Since my project calls for a frequency doubler, which I want to
implement with a XOR gate, I wanted to use one XOR gate of a 74HC86 as
oscillator. Remaining gates would work as buffer, delay line, digital
mixer.

(I have Googled newsgroups and found an interesting discussion about XOR
frequency doublers, so I am aware of its limitations.)

So I moved the oscillator circuitry (R; C; R, XTAL; C) from the 74HC14
to the 74HC86, pulling the other input of the XOR gate to "1", so that I
would produce an inverter.

Nothing happens. I used a 10.0 MHz XTAL.

I understand that the 74HC14 has Schmitt trigger inputs and that a
74HC86 might have higher propagation delays. Still, is it possible to
use a XOR gate as an inverter and oscillator? Do I overlook something?

In the end I recovered the 74HC14 oscillator, but this adds one
component to the final circuit I have in mind that wastes energy, space
and is underutilized.

Looking forward to your always helpful replies!
Paolo IK1ZYW