Magnetically tuned klystrons for wide-band frequency modulation applications

This paper describes the application of a ferrite-tuned -band klystron to produce very wide-band frequency modulation with exceptionally low accompanying power variation. By perturbation techniques, a theoretical analysis of the magnetically tuned klystron is made in terms of the static and dynamic intrinisic properties of the ferrite. The observed operating characteristics show good agreement with the predicted behavior. The design of a practical magnetically tuned X-band klystron for frequency modulation application is discussed in detail. Designs which included a fixed bias field transverse to the tuning field allowed frequency deviation over a 600-Mc bandwidth to be obtained with very good linearity at modulation frequencies below 500 cps. The change in power was less than ± 6 per cent. Another model permitted modulation frequency components up to 50 kc but tuning bandwidth was reduced to 300 Mc.