In article vLWrc.13935$JC5.1310262@attbi_s54, Scott Stephens
writes
ddwyer wrote:


A multimode delay line oscillator can be
achieved by introducing a peaked gain response at the required overtone.

How? A tuned filter? There's a hole in the bucket... (circular
implementation)
Not quite.
The delay line can be multioctave and the phase slope will be
proportional the the delay. It may go through many 360 deg phase
rotations over its bandwidth.
An amplifier with much shallower phase slope can still have sufficient
selectivity to determine which particular 360 deg rotation is
oscillated. This has been done successfully with PAL bulk acoustic delay
lines.
The following is more contentious but I think it will work

Alternatively with more than 360 degrees phase shift the oscillation
which cannot change frequency instantaneously can be induced by
continuously increasing phase and jumping from 360 to 0 degrees to sweep
over multimodes.

Wha? Could you expand on that?
Not a lot. progressively changing phase with varicaps cannot carry on
but the circuit does not know the difference between 360deg and 0 deg.
Goniometers? used to do this for direction finding.
Can also be done with mixers but that is more of a circular argument.


Thanks


--
ddwyer