Frequency synchronization of an X-band reflex klystron

Abstract

The paper gives results obtained in synchronizing an X-band reflex klystron oscillator to a source of power at a similar frequency. The power is fed through an isolator to the oscillator so that synchronization is attempted in one direction only. The results show the variation of control range and power output with various parameters of the system. A number of applications of the phenomenon are discussed.The valve used in the work was the K302 with an output of about 20 mW. An incident power of less than 1 μW is sufficient to lock this valve.In addition, the energy distribution of the noise in a small bandwidth in the range 3–80 kc/s from the carrier was investigated for both locked and unlocked oscillator. Brief mention is made of the method of measurement. Using a source of locking power with a narrow energy distribution the relationship between this energy distribution and that of the locked oscillator is discussed as a function of incident power. It is shown that the amplitude-modulation noise distribution of the locked oscillator becomes identical to that of the locking source independently of the locking power, always provided that it remains locked and that the frequency-modulation noise distribution is a function of the locking power, being identical to that of the source for large locking powers and degenerating as the locking power is reduced. This provides a means of improving the noise distribution of a noisy reflex oscillator.The f.m. noise spectrum is measured in terms of the r.m.s. deviation in a small bandwidth at some distance from the carrier. It is shown that for a small deviation ratio (δ) the power in the bandwidth of measurement is given by ½δ2, relative to the carrier power.The contribution of the local-oscillator noise spectrum to the noise spectrum of the i.f. output from a balanced mixer is investigated and is shown to be as important as that of the noise distribution in the signal.