1. W. S. Peecival:British Patent Specification No. 460, 562.
2. E. L. Ginzton, W. R. Hewlett, J. H. Jasberg andJ. D. Noe:P.I.R.E.,36, 956 (1948).
3. For a description of the theory and a list of references seeI. A. D. Lewis andP. H. Wells:Millimicrosecond Pulse Techniques (London, 1954).
4. H. E. Kallmann:P.I.R.E.,34, 646 (1946).
5. F. E. Terman:Radio Engineers’ Handbook (New York, 1943), pp. 53 to 55.