Hi Most Gunn oscillators have very basic internals. Isolation between the “oscillator” and the “output” is rarely very good. Injection locking one is quite easy. It’s often done as the final step in a microwave LO multiplier chain.
Bob On Oct 8, 2014, at 6:54 PM, Bruce Hunter via time-nuts <time-nuts@febo.com> wrote: > > This is certainly an interesting phenomenon. A couple of possible > explanations come to mind. > > First, if the pair of Gunn sources are not really locked and are oscillating > at two different frequencies, the resulting voltage envelope would peak at > about double the voltage of either oscillator. This might cause a power > detector (that senses only voltage) to read about a 6 dB increase over one > Gunn oscillator alone. The waveguide low-frequency cutoff would not > eliminate the envelope modulation as the low-frequency component is encoded > as a pair of sidebands close in frequency to the carrier. Think of a signal > generator modulated with 1 kHz square-wave for use with a tuned detector. > > A second possible explanation involves the combined internal impedance of the > Gunn diode oscillators. Summing two of them may alter the operating point > along the E/I negative resistance curves, changing the combined generator > impedance, and possibly improving device efficiency. These devices are > relatively inefficient anyway (about 1%), so an increase or decrease in the > dc input power is not a good indication of what's going on in the generation > of RF. > > Bruce, KG6OJI > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
