"Alan Yates" wrote in message
...

[snip]

The cathode circuit looks very much like it is a self-quenching circuit,
but the diagram below suggests it is separately quenched? This is an IFF
transponder? The feedback loop is interesting, looks like reflexing to
me. I'd guess the entire circuit oscillates at the quench frequency and
the modulation is recovered by filtering that output?

It's an IFF responder and it's separately quenched. When lit by radar, it
emits a pulse of characteristic duration and much stronger than a passive
reflection.

The book also contains examples of the same oscillator circuit but without
the cathode choke i.e. grounded cathode.