TABLE OF CONTENTS Personnel vi Publications and Reports ix Introduction xi I. Physical Electronics 1 Research Objectives 1 Electron Emission Problems 1 Reflection of Slow Electrons at a Metal Surface 1 Experimental Studies 2 High-Vacuum MassITron 2 The Spectral Emissivity of Tungsten 3 Cleanup of Helium in Ionization Gauges 4 Ionization Gauge Control Circuit 5 II. Microwave Gaseous Discharges 8 Research Objectives 8 High-Density Microwave Gaseous Discharges 8 Microwave Determination of the Probability of Collision of Slow Electrons in Neon 9 III. Solid State Physics 13 Electrical Breakdown in Germanium at Microwave Frequencies 13 IV. Low Temperature Physics 14 Research Objectives 14 Measurement of the Thermodynamic Equation of State of Paramagnetic Salts 14 V. Microwave Spectroscopy 18 Research Objectives 18 VI. Magnet Laboratory Research 19 Research Objectives 19 Nuclear Orientation in Mercury Vapor 19 Stepwise Excitation in Mercury 19 Nuclear Resonances in Solids 20 VII. Microwave Tube Research 21 Research Objectives 21 Minimum Noise Figure of Longitudinal Beam Amplifiers 21 Low-Noise Electron Beams 26 Beam Noise Measurements 29 Million- Electron-Volt Tube 30 VIII. Atomic Beam Research 31 Research Objectives 31 Electron Multipliers 31 Precision Measurements of the Hyperfine Levels of Cs 1 3 3 31 Stark Effect on Hyperfine Structure 32 6 9 7 1 Hyperfine Structure of the 2 P 1 / 2 State in Ga and Ga 32 Hyperfine Structure of Halogens 32 IX. Stroboscopic Research 34 Research Objectives 34 Characteristics of the FT-17A Flashtube 34 X. Statistical Communication Theory 43 Research Objectives 43 A Theorem Concerning Noise Figures 43 Calculation of Second-Order Correlation Functions 45 Measurement of Second-Order Autocorrelation Functions 49 Autocorrelation Functions of Poisson Waves 56 XI. Processing and Transmission of Information 63 Research Objectives 63 The Synthesis of Iterative Switching Circuits 63 Sequential Switching Systems with Closed Memory 67 XII. Transistor Circuits 72 Research Objectives 72 Constant Resistance AGC Attenuators for Transistor Amplifiers 72 The Operations of Multiplication and Division 77 XIII. Semiconductor Noise 78 Research Objectives 78 A Theory of 1/f Noise in Semiconductor Filaments 79 Role of Surface Oxide Layers in 1/f Noise 89 XIV. Speech Analysis 92 Research Objectives 92 XV. Mechanical Translation 93 Research Objectives 93 Syntactic Categories 93 XVI. Visual Replacement Projects 96 Research Objectives 96 Combined Step-Down and Obstacle Detector 96 XVII. Communications Biophysics 99 Research Objectives 99 Physiological and Psychological Constraints upon Auditory Theory 100 XVIII. Neurophysiology 101 Research Objectives 101 XIX. Analog Computer Research 102 Research Objectives 102 Active Network Synthesis 102 Network Synthesis with Distributed Elements 108 Piecewise Linear Network Theory 108 XX. Network Synthesis 113 Research Objectives 113 XXI. Multipath Transmission 114 Research Objectives 114 Cascaded Bandpass Limiters 114 Narrow-Band Limiting 117.