In article lXI_b.395225$na.763604@attbi_s04, Harold E. Johnson
writes

"Paul Burridge" wrote in message
news

Hi,

I'm trying to track down the name for a certain type of oscillator
which I dimly recall seeing in an old book called Radio & Line
Transmission that I bought and lost over 3 decades ago.
In simple terms, it has a crystal in the base/emitter circuit and a
C/L tank for the resonant frequency of the crystal in the collector
circuit. In this way it can't flip into an overtone since it only has
gain at the crystal's fundamental. Anyone know the name for it?

Why don't you think the crystal goes low impedance at it's odd harmonics? If
you'll design the circuit properly, it will give no trouble with overtone
operation. Don't remember ever having any problems selecting one to operate
on the fundamental, usually, it's selecting between 5th and 7th overtone or
7th and 9th that gets a little sticky.

W4ZCB


A universal series resonant circuit "Butler?" meets most of your
criteria. I dont like these names myself. Collector to +ve supply via
tank LC with the C = 2 C in series the base decoupled to ground with a
potential divider to set base bias and a low value (220R?) in the
emitter to ground.
The crystal goes from the junction of the 2 tapped capacitors and the
emitter. The 2 Cs are arranged to lower the o/p impedance from the
collector tank i.e. the C nearest the collector would be 100pF and the C
to the +ve supply 330pF. With the LC arranged to resonate at the crystal
frequency.
The beauty of the circuit is that the crystal can be replaced by a 50R
resistor and the circuit L and C tweaked to oscillate at the crystal
freq. Can be used to select overtone or fundamental.

--
ddwyer